Migration

OpenShift Container Platform 4.4

Migrating from OpenShift Container Platform 3 to 4

Red Hat OpenShift Documentation Team

Abstract

This document provides instructions for migrating your OpenShift Container Platform cluster from version 3 to version 4.

Chapter 1. Migrating OpenShift Container Platform 3 to 4

1.1. About migrating OpenShift Container Platform 3 to 4

OpenShift Container Platform 4 includes new technologies and functionality that results in a cluster that is self-managing, flexible, and automated. The way that OpenShift Container Platform 4 clusters are deployed and managed drastically differs from OpenShift Container Platform 3.

To successfully transition from OpenShift Container Platform 3 to OpenShift Container Platform 4, it is important that you review the following information:

Planning your transition
Learn about the differences between OpenShift Container Platform versions 3 and 4. Prior to transitioning, be sure that you have reviewed and prepared for storage, networking, logging, security, and monitoring considerations.
Performing your migration

Learn about and use the tools to perform your migration:

  • Cluster Application Migration (CAM) tool to migrate your application workloads
  • Control Plane Migration Assistant (CPMA) to migrate your control plane

1.2. Planning your migration

Before performing your migration to OpenShift Container Platform 4.4, it is important to take the time to properly plan for the transition. OpenShift Container Platform 4 introduces architectural changes and enhancements, so the procedures that you used to manage your OpenShift Container Platform 3 cluster might not apply for OpenShift Container Platform 4.

Note

This planning document assumes that you are transitioning from OpenShift Container Platform 3.11 to OpenShift Container Platform 4.4.

This document provides high-level information on the most important differences between OpenShift Container Platform 3 and OpenShift Container Platform 4 and the most noteworthy migration considerations. For detailed information on configuring your OpenShift Container Platform 4 cluster, review the appropriate sections of the OpenShift Container Platform documentation. For detailed information on new features and other notable technical changes, review the OpenShift Container Platform 4.4 release notes.

It is not possible to upgrade your existing OpenShift Container Platform 3 cluster to OpenShift Container Platform 4. You must start with a new OpenShift Container Platform 4 installation. Tools are available to assist in migrating your control plane settings and application workloads.

1.2.1. Comparing OpenShift Container Platform 3 and OpenShift Container Platform 4

With OpenShift Container Platform 3, administrators individually deployed Red Hat Enterprise Linux (RHEL) hosts, and then installed OpenShift Container Platform on top of these hosts to form a cluster. Administrators were responsible for properly configuring these hosts and performing updates.

OpenShift Container Platform 4 represents a significant change in the way that OpenShift Container Platform clusters are deployed and managed. OpenShift Container Platform 4 includes new technologies and functionality, such as Operators, MachineSets, and Red Hat Enterprise Linux CoreOS (RHCOS), which are core to the operation of the cluster. This technology shift enables clusters to self-manage some functions previously performed by administrators. This also ensures platform stability and consistency, and simplifies installation and scaling.

For more information, see OpenShift Container Platform architecture.

1.2.1.1. Architecture differences

Immutable infrastructure

OpenShift Container Platform 4 uses Red Hat Enterprise Linux CoreOS (RHCOS), which is designed to run containerized applications, and provides efficient installation, Operator-based management, and simplified upgrades. RHCOS is an immutable container host, rather than a customizable operating system like RHEL. RHCOS enables OpenShift Container Platform 4 to manage and automate the deployment of the underlying container host. RHCOS is a part of OpenShift Container Platform, which means that everything runs inside a container and is deployed using OpenShift Container Platform.

In OpenShift Container Platform 4, control plane nodes must run RHCOS, ensuring that full-stack automation is maintained for the control plane. This makes rolling out updates and upgrades a much easier process than in OpenShift Container Platform 3.

For more information, see Red Hat Enterprise Linux CoreOS.

Operators

Operators are a method of packaging, deploying, and managing a Kubernetes application. Operators ease the operational complexity of running another piece of software. They watch over your environment and use the current state to make decisions in real time. Advanced Operators are designed to upgrade and react to failures automatically.

For more information, see Understanding Operators.

1.2.1.2. Installation and update differences

Installation process

To install OpenShift Container Platform 3.11, you prepared your Red Hat Enterprise Linux (RHEL) hosts, set all of the configuration values your cluster needed, and then ran an Ansible playbook to install and set up your cluster.

In OpenShift Container Platform 4.4, you use the OpenShift installation program to create a minimum set of resources required for a cluster. Once the cluster is running, you use Operators to further configure your cluster and to install new services. After first boot, Red Hat Enterprise Linux CoreOS (RHCOS) systems are managed by the Machine Config Operator (MCO) that runs in the OpenShift Container Platform cluster.

For more information, see Installation process.

If you want to add RHEL worker machines to your OpenShift Container Platform 4.4 cluster, you use an Ansible playbook to join the RHEL worker machines after the cluster is running. For more information, see Adding RHEL compute machines to an OpenShift Container Platform cluster.

Infrastructure options

In OpenShift Container Platform 3.11, you installed your cluster on infrastructure that you prepared and maintained. In addition to providing your own infrastructure, OpenShift Container Platform 4 offers an option to deploy a cluster on infrastructure that the OpenShift Container Platform installation program provisions and the cluster maintains.

For more information, see OpenShift Container Platform installation overview.

Upgrading your cluster

In OpenShift Container Platform 3.11, you upgraded your cluster by running Ansible playbooks. In OpenShift Container Platform 4.4, the cluster manages its own updates, including updates to Red Hat Enterprise Linux CoreOS (RHCOS) on cluster nodes. You can easily upgrade your cluster by using the web console or by using the oc adm upgrade command from the OpenShift CLI and the Operators will automatically upgrade themselves. If your OpenShift Container Platform 4.4 cluster has Red Hat Enterprise Linux worker machines, then you will still need to run an Ansible playbook to upgrade those worker machines.

For more information, see Updating clusters.

1.2.2. Migration considerations

Review the changes and other considerations that might affect your transition from OpenShift Container Platform 3.11 to OpenShift Container Platform 4.

1.2.2.1. Storage considerations

Review the following storage changes to consider when transitioning from OpenShift Container Platform 3.11 to OpenShift Container Platform 4.4.

Local volume persistent storage

Local storage is only supported by using the Local Storage Operator in OpenShift Container Platform 4.4. It is not supported to use the local provisioner method from OpenShift Container Platform 3.11.

For more information, see Persistent storage using local volumes.

FlexVolume persistent storage

The FlexVolume plug-in location changed from OpenShift Container Platform 3.11. The new location in OpenShift Container Platform 4.4 is /etc/kubernetes/kubelet-plugins/volume/exec. Attachable FlexVolume plug-ins are no longer supported.

For more information, see Persistent storage using FlexVolume.

Container Storage Interface (CSI) persistent storage

Persistent storage using the Container Storage Interface (CSI) was Technology Preview in OpenShift Container Platform 3.11. CSI version 1.1.0 is fully supported in OpenShift Container Platform 4.4, but does not ship with any CSI drivers. You must install your own driver.

For more information, see Persistent storage using the Container Storage Interface (CSI).

Red Hat OpenShift Container Storage

Red Hat OpenShift Container Storage 3, which is available for use with OpenShift Container Platform 3.11, uses Red Hat Gluster Storage as the backing storage.

Red Hat OpenShift Container Storage 4, which is available for use with OpenShift Container Platform 4, uses Red Hat Ceph Storage as the backing storage.

For more information, see Persistent storage using Red Hat OpenShift Container Storage and the interoperability matrix article.

Unsupported persistent storage options

Support for the following persistent storage options from OpenShift Container Platform 3.11 has changed in OpenShift Container Platform 4.4:

  • GlusterFS is no longer supported.
  • CephFS as a standalone product is no longer supported.
  • Ceph RBD as a standalone product is no longer supported.

If you used of one these in OpenShift Container Platform 3.11, you must choose a different persistent storage option for full support in OpenShift Container Platform 4.4.

For more information, see Understanding persistent storage.

1.2.2.2. Networking considerations

Review the following networking changes to consider when transitioning from OpenShift Container Platform 3.11 to OpenShift Container Platform 4.4.

Network isolation mode

The default network isolation mode for OpenShift Container Platform 3.11 was ovs-subnet, though users frequently switched to use ovn-multitenant. The default network isolation mode for OpenShift Container Platform 4.4 is now NetworkPolicy.

If your OpenShift Container Platform 3.11 cluster used the ovs-subnet or ovs-multitenant mode, it is recommended to switch to the NetworkPolicy mode for your OpenShift Container Platform 4.4 cluster. NetworkPolicy is supported upstream, is more flexible, and also provides the functionality that ovs-multitenant does. If you want to maintain the ovs-multitenant behavior while using NetworkPolicy in OpenShift Container Platform 4.4, follow the steps to configure multitenant isolation using NetworkPolicy.

For more information, see About network policy.

Encrypting traffic between hosts

In OpenShift Container Platform 3.11, you could use IPsec to encrypt traffic between hosts. OpenShift Container Platform 4.4 does not support IPsec. It is recommended to use Red Hat OpenShift Service Mesh to enable mutual TLS between services.

For more information, see Understanding Red Hat OpenShift Service Mesh.

1.2.2.3. Logging considerations

Review the following logging changes to consider when transitioning from OpenShift Container Platform 3.11 to OpenShift Container Platform 4.4.

Deploying cluster logging

OpenShift Container Platform 4 provides a simple deployment mechanism for cluster logging, by using a Cluster Logging custom resource. Once deployed, the cluster logging experience is the same as it was in OpenShift Container Platform 3.11.

For more information, see About deploying and configuring cluster logging.

Aggregated logging data

You cannot transition your aggregate logging data from OpenShift Container Platform 3.11 into your new OpenShift Container Platform 4 cluster.

For more information, see About cluster logging.

1.2.2.4. Security considerations

Review the following security changes to consider when transitioning from OpenShift Container Platform 3.11 to OpenShift Container Platform 4.4.

Unauthenticated access to discovery endpoints

In OpenShift Container Platform 3.11, an unauthenticated user could access the discovery endpoints (for example, /api/* and /apis/*). For security reasons, unauthenticated access to the discovery endpoints is no longer allowed in OpenShift Container Platform 4.4. If you do need to allow unauthenticated access, you can configure the RBAC settings as necessary; however, be sure to consider the security implications as this can expose internal cluster components to the external network.

Identity providers

Configuration for identity providers has changed for OpenShift Container Platform 4, including the following notable changes:

  • The request header identity provider in OpenShift Container Platform 4.4 requires mutual TLS, where in OpenShift Container Platform 3.11 it did not.
  • The configuration of the OpenID Connect identity provider was simplified in OpenShift Container Platform 4.4. It now obtains data, which previously had to specified in OpenShift Container Platform 3.11, from the provider’s /.well-known/openid-configuration endpoint.

For more information, see Understanding identity provider configuration.

1.2.2.5. Monitoring considerations

Review the following monitoring changes to consider when transitioning from OpenShift Container Platform 3.11 to OpenShift Container Platform 4.4.

Alert for monitoring infrastructure availability

The default alert that triggers to ensure the availability of the monitoring structure was called DeadMansSwitch in OpenShift Container Platform 3.11. This was renamed to Watchdog in OpenShift Container Platform 4. If you had PagerDuty integration set up with this alert in OpenShift Container Platform 3.11, you must set up the PagerDuty integration for the Watchdog alert in OpenShift Container Platform 4.

For more information, see Applying custom Alertmanager configuration.

1.3. Migrating application workloads from OpenShift Container Platform 3.7 to 4.4

You can migrate application workloads from OpenShift Container Platform 3.7 (and later) to OpenShift Container Platform 4.4 with the Cluster Application Migration (CAM) tool. The CAM tool enables you to control the migration and to minimize application downtime.

The CAM tool’s web console and API, based on Kubernetes Custom Resources, enable you to migrate stateful application workloads at the granularity of a namespace.

Optionally, you can use the Control Plane Migration Assistant (CPMA) to assist you in migrating control plane settings.

Important

Before you begin your migration, be sure to review the information on planning your migration.

1.3.1. Migration prerequisites

  • The source cluster must be OpenShift Container Platform 3.7, 3.9, 3.10, or 3.11.
  • You must have podman installed.
  • You must have cluster-admin privileges on all clusters.
  • The source and target clusters must have unrestricted network access to the replication repository.
  • The cluster on which the Migration controller is installed must have unrestricted access to the other clusters.
  • If your application uses images from the openshift namespace, the required versions of the images must be present on the target cluster.

    If the required images are not present, you must update the imagestreamtags references to use an available version that is compatible with your application. If the imagestreamtags cannot be updated, you can manually upload equivalent images to the application namespaces and update the applications to reference them.

    The following imagestreamtags have been removed from OpenShift Container Platform 4.2:

    • dotnet:1.0, dotnet:1.1, dotnet:2.0
    • dotnet-runtime:2.0
    • mariadb:10.1
    • mongodb:2.4, mongodb:2.6
    • mysql:5.5, mysql:5.6
    • nginx:1.8
    • nodejs:0.10, nodejs:4, nodejs:6
    • perl:5.16, perl:5.20
    • php:5.5, php:5.6
    • postgresql:9.2, postgresql:9.4, postgresql:9.5
    • python:3.3, python:3.4
    • ruby:2.0, ruby:2.2

      The following imagestreamtags have been removed from OpenShift Container Platform 4.4:

    • dotnet: 2.2
    • dotnet-runtime: 2.2
    • nginx: 1.12
    • nodejs: 8, 8-RHOAR, 10-SCL
    • perl:5.24
    • php: 7.0, 7.1
    • redis: 3.2

1.3.2. Understanding the Cluster Application Migration tool

The Cluster Application Migration (CAM) tool enables you to migrate Kubernetes resources, persistent volume data, and internal container images from an OpenShift Container Platform source cluster to an OpenShift Container Platform 4.4 target cluster, using the CAM web console or the Kubernetes API.

Migrating an application with the CAM web console involves the following steps:

  1. Install the Cluster Application Migration Operator on all clusters.

    Note

    The Cluster Application Migration Operator installs the CAM tool (CAM web console and Migration controller) on the target cluster by default. You can configure the Migration controller to install the CAM tool on another cluster. The cluster on which the CAM tool is installed is referred to as the CAM tool cluster.

  2. Configure the replication repository, an intermediate object storage that the CAM tool uses to migrate data.
  3. Add the source cluster to the CAM web console.
  4. Add the replication repository to the CAM web console.
  5. Create a migration plan, with one of the following data migration options:

    • Copy: The CAM tool copies the data from the source cluster to the replication repository, and from the replication repository to the target cluster.

      migration PV copy
    • Move: The CAM tool unmounts a remote volume (for example, NFS) from the source cluster, creates a PV resource on the target cluster pointing to the remote volume, and then mounts the remote volume on the target cluster. Applications running on the target cluster use the same remote volume that the source cluster was using. The remote volume must be accessible to the source and target clusters.

      Note

      Although the replication repository does not appear in this diagram, it is required for the actual migration.

      migration PV move
  6. Run the migration plan, with one of the following options:

    • Stage (optional) copies data to the target cluster without stopping the application.

      Staging can be run multiple times so that most of the data is copied to the target before migration. This minimizes the actual migration time and application downtime.

    • Migrate stops the application on the source cluster and recreates its resources on the target cluster. Optionally, you can migrate the workload without stopping the application.
OCP 3 to 4 App migration

1.3.3. Understanding migration hooks

You can use migration hooks to run Ansible playbooks at certain points during the migration. The hooks are added when you create a migration plan.

Note

If you do not want to use Ansible playbooks, you can create a custom container image and add it to a migration plan.

Migration hooks perform tasks such as customizing application quiescence, manually migrating unsupported data types, and updating applications after migration.

A single migration hook runs on a source or target cluster at one of the following migration steps:

  • PreBackup: Before backup tasks are started on the source cluster
  • PostBackup: After backup tasks are complete on the source cluster
  • PreRestore: Before restore tasks are started on the target cluster
  • PostRestore: After restore tasks are complete on the target cluster

    You can assign one hook to each migration step, up to a maximum of four hooks for a single migration plan.

The default hook-runner image is registry.redhat.io/rhcam-1-2/openshift-migration-hook-runner-rhel7. This image is based on Ansible Runner and includes python-openshift for Ansible Kubernetes resources and an updated oc binary. You can also create your own hook image with additional Ansible modules or tools.

The Ansible playbook is mounted on a hook container as a ConfigMap. The hook container runs as a Job on a cluster with a specified service account and namespace. The Job runs, even if the initial Pod is evicted or killed, until it reaches the default backoffLimit (6) or successful completion.

1.4. Deploying the Cluster Application Migration (CAM) tool

Deploying the Cluster Application Migration (CAM) tool requires installing the Cluster Application Migration Operator on the OpenShift Container Platform 3 source and OpenShift Container Platform 4.4 target clusters.

1.4.1. Installing the Cluster Application Migration Operator on an OpenShift Container Platform 3 source cluster

You can install the Cluster Application Migration Operator manually on an OpenShift Container Platform 3.7 (or later) source cluster, which does not support OLM.

Prerequisites

  • You must have podman installed.
  • Your OpenShift Container Platform 3 cluster must be configured to pull images from registry.redhat.io.

    To pull images, you must create an imagestreamsecret and copy it to each node in your cluster.

Procedure

  1. Log in to registry.redhat.io with your Red Hat Customer Portal credentials:

    $ sudo podman login registry.redhat.io
    Note

    If your system is configured for rootless Podman containers, sudo is not required for this procedure.

  2. Download the operator.yml file:

    $ sudo podman cp $(sudo podman create registry.redhat.io/rhcam-1-1/openshift-migration-rhel7-operator:v1.1):/operator.yml ./
  3. Download the controller-3.yml file:

    $ sudo podman cp $(sudo podman create registry.redhat.io/rhcam-1-1/openshift-migration-rhel7-operator:v1.1 ):/controller-3.yml ./
  4. Log in to your OpenShift Container Platform 3 cluster.
  5. Verify that the cluster can authenticate with registry.redhat.io:

    $ oc run test --image registry.redhat.io/ubi8 --command sleep infinity
  6. Create the Cluster Application Migration Operator CR object:

    $ oc create -f operator.yml
    namespace/openshift-migration created
    rolebinding.rbac.authorization.k8s.io/system:deployers created
    serviceaccount/migration-operator created
    customresourcedefinition.apiextensions.k8s.io/migrationcontrollers.migration.openshift.io created
    role.rbac.authorization.k8s.io/migration-operator created
    rolebinding.rbac.authorization.k8s.io/migration-operator created
    clusterrolebinding.rbac.authorization.k8s.io/migration-operator created
    deployment.apps/migration-operator created
    Error from server (AlreadyExists): error when creating "./operator.yml":
    rolebindings.rbac.authorization.k8s.io "system:image-builders" already exists 1
    Error from server (AlreadyExists): error when creating "./operator.yml":
    rolebindings.rbac.authorization.k8s.io "system:image-pullers" already exists 2
    1 2
    You can ignore the Error from server (AlreadyExists) messages. They are caused by the Cluster Application Migration Operator creating resources for earlier versions of OpenShift Container Platform 3 that are provided in later releases.
  7. Create the Migration controller CR object:

    $ oc create -f controller-3.yml
  8. Verify that the Velero and Restic Pods are running:

    $ oc get pods -n openshift-migration

1.4.2. Installing the Cluster Application Migration Operator on an OpenShift Container Platform 4.4 target cluster

You can install the Cluster Application Migration Operator on an OpenShift Container Platform 4.4 target cluster with OLM.

The Cluster Application Migration Operator installs the CAM tool on the target cluster by default. If you want to install the CAM tool on a different cluster, you must update the Migration controller configuration so that the Cluster Application Migration Operator does not install the CAM tool on this cluster.

Procedure

  1. In the OpenShift Container Platform web console, click OperatorsOperatorHub.
  2. Use the Filter by keyword field (in this case, Migration) to find the Cluster Application Migration Operator.
  3. Select the Cluster Application Migration Operator and click Install.
  4. On the Create Operator Subscription page, select the openshift-migration namespace, and specify an approval strategy.
  5. Click Subscribe.

    On the Installed Operators page, the Cluster Application Migration Operator appears in the openshift-migration project with the status InstallSucceeded.

  6. Under Provided APIs, click View 12 more…​.
  7. Click Create NewMigrationController.
  8. Click Create.
  9. Click WorkloadsPods to verify that the Controller Manager, Migration UI, Restic, and Velero Pods are running.

1.4.3. Launching the CAM web console

You can launch the CAM web console in a browser.

Procedure

  1. Log in to the OpenShift Container Platform cluster on which you have installed the CAM tool.
  2. Obtain the CAM web console URL by entering the following command:

    $ oc get -n openshift-migration route/migration -o go-template='https://{{ .spec.host }}'
    https://migration-openshift-migration.apps.<cluster>.openshift.com
  3. Launch a browser and navigate to the CAM web console.

    Note

    If you try to access the CAM web console immediately after installing the Cluster Application Migration Operator, the console may not load because the Operator is still configuring the cluster. Wait a few minutes and retry.

  4. If you are using self-signed CA certificates, you will be prompted to accept the CA certificate of the source cluster’s API server. The web page guides you through the process of accepting the remaining certificates.
  5. Log in with your OpenShift Container Platform username and password.

1.5. Configuring a replication repository

You must configure an object storage to use as a replication repository. The Cluster Application Migration tool copies data from the source cluster to the replication repository, and then from the replication repository to the target cluster, using either the file system or the snapshot data copy method.

The following storage providers are supported:

1.5.1. Understanding the data copy methods for migration

The CAM tool supports the file system and snapshot data copy methods for migrating data from the source cluster to the target cluster. You can select a method that is suited for your environment and is supported by your storage provider.

1.5.1.1. File system copy method

The CAM tool copies data files from the source cluster to the replication repository, and from there to the target cluster.

Table 1.1. File system copy method summary

BenefitsLimitations
  • Clusters can have different storage classes
  • Supported for all S3 storage providers
  • Optional data verification with checksum
  • Slower than the snapshot copy method
  • Optional data verification significantly reduces performance

1.5.1.2. Snapshot copy method

The CAM tool copies a snapshot of the source cluster’s data to a cloud provider’s object storage, configured as a replication repository. The data is restored on the target cluster.

AWS, Google Cloud Provider, and Microsoft Azure support the snapshot copy method.

Table 1.2. Snapshot copy method summary

BenefitsLimitations
  • Faster than the file system copy method
  • Cloud provider must support snapshots.
  • Clusters must be on the same cloud provider.
  • Clusters must be in the same location or region.
  • Clusters must have the same storage class.
  • Storage class must be compatible with snapshots.

1.5.2. Configuring a Multi-Cloud Object Gateway storage bucket as a replication repository

You can install the OpenShift Container Storage Operator and configure a Multi-Cloud Object Gateway (MCG) storage bucket as a replication repository.

1.5.2.1. Installing the OpenShift Container Storage Operator

You can install the OpenShift Container Storage Operator from OperatorHub.

Procedure

  1. In the OpenShift Container Platform web console, click OperatorsOperatorHub.
  2. Use Filter by keyword (in this case, OCS) to find the OpenShift Container Storage Operator.
  3. Select the OpenShift Container Storage Operator and click Install.
  4. Select an Update Channel, Installation Mode, and Approval Strategy.
  5. Click Subscribe.

    On the Installed Operators page, the OpenShift Container Storage Operator appears in the openshift-storage project with the status Succeeded.

1.5.2.2. Creating the Multi-Cloud Object Gateway storage bucket

You can create the Multi-Cloud Object Gateway (MCG) storage bucket’s Custom Resources (CRs).

Procedure

  1. Log in to the OpenShift Container Platform cluster:

    $ oc login
  2. Create the NooBaa CR configuration file, noobaa.yml, with the following content:

    apiVersion: noobaa.io/v1alpha1
    kind: NooBaa
    metadata:
      name: noobaa
      namespace: openshift-storage
    spec:
     dbResources:
       requests:
         cpu: 0.5 1
         memory: 1Gi
     coreResources:
       requests:
         cpu: 0.5 2
         memory: 1Gi
    1 2
    For a very small cluster, you can change the cpu value to 0.1.
  3. Create the NooBaa object:

    $ oc create -f noobaa.yml
  4. Create the BackingStore CR configuration file, bs.yml, with the following content:

    apiVersion: noobaa.io/v1alpha1
    kind: BackingStore
    metadata:
      finalizers:
      - noobaa.io/finalizer
      labels:
        app: noobaa
      name: mcg-pv-pool-bs
      namespace: openshift-storage
    spec:
      pvPool:
        numVolumes: 3 1
        resources:
          requests:
            storage: 50Gi 2
        storageClass: gp2 3
      type: pv-pool
    1
    Specify the number of volumes in the PV pool.
    2
    Specify the size of the volumes.
    3
    Specify the storage class.
  5. Create the BackingStore object:

    $ oc create -f bs.yml
  6. Create the BucketClass CR configuration file, bc.yml, with the following content:

    apiVersion: noobaa.io/v1alpha1
    kind: BucketClass
    metadata:
      labels:
        app: noobaa
      name: mcg-pv-pool-bc
      namespace: openshift-storage
    spec:
      placementPolicy:
        tiers:
        - backingStores:
          - mcg-pv-pool-bs
          placement: Spread
  7. Create the BucketClass object:

    $ oc create -f bc.yml
  8. Create the ObjectBucketClaim CR configuration file, obc.yml, with the following content:

    apiVersion: objectbucket.io/v1alpha1
    kind: ObjectBucketClaim
    metadata:
      name: migstorage
      namespace: openshift-storage
    spec:
      bucketName: migstorage 1
      storageClassName: openshift-storage.noobaa.io
      additionalConfig:
        bucketclass: mcg-pv-pool-bc
    1
    Record the bucket name for adding the replication repository to the CAM web console.
  9. Create the ObjectBucketClaim object:

    $ oc create -f obc.yml
  10. Watch the resource creation process to verify that the ObjectBucketClaim status is Bound:

    $ watch -n 30 'oc get -n openshift-storage objectbucketclaim migstorage -o yaml'

    This process can take five to ten minutes.

  11. Obtain and record the following values, which are required when you add the replication repository to the CAM web console:

    • S3 endpoint:

      $ oc get route -n openshift-storage s3
    • S3 provider access key:

      $ oc get secret -n openshift-storage migstorage -o go-template='{{ .data.AWS_ACCESS_KEY_ID }}' | base64 -d
    • S3 provider secret access key:

      $ oc get secret -n openshift-storage migstorage -o go-template='{{ .data.AWS_SECRET_ACCESS_KEY }}' | base64 -d

1.5.3. Configuring an AWS S3 storage bucket as a replication repository

You can configure an AWS S3 storage bucket as a replication repository.

Prerequisites

  • The AWS S3 storage bucket must be accessible to the source and target clusters.
  • You must have the AWS CLI installed.
  • If you are using the snapshot copy method:

    • You must have access to EC2 Elastic Block Storage (EBS).
    • The source and target clusters must be in the same region.
    • The source and target clusters must have the same storage class.
    • The storage class must be compatible with snapshots.

Procedure

  1. Create an AWS S3 bucket:

    $ aws s3api create-bucket \
        --bucket <bucket_name> \ 1
        --region <bucket_region> 2
    1
    Specify your S3 bucket name.
    2
    Specify your S3 bucket region, for example, us-east-1.
  2. Create the IAM user velero:

    $ aws iam create-user --user-name velero
  3. Create an EC2 EBS snapshot policy:

    $ cat > velero-ec2-snapshot-policy.json <<EOF
    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Effect": "Allow",
                "Action": [
                    "ec2:DescribeVolumes",
                    "ec2:DescribeSnapshots",
                    "ec2:CreateTags",
                    "ec2:CreateVolume",
                    "ec2:CreateSnapshot",
                    "ec2:DeleteSnapshot"
                ],
                "Resource": "*"
            }
        ]
    }
    EOF
  4. Create an AWS S3 access policy for one or for all S3 buckets:

    $ cat > velero-s3-policy.json <<EOF
    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Effect": "Allow",
                "Action": [
                    "s3:GetObject",
                    "s3:DeleteObject",
                    "s3:PutObject",
                    "s3:AbortMultipartUpload",
                    "s3:ListMultipartUploadParts"
                ],
                "Resource": [
                    "arn:aws:s3:::<bucket_name>/*" 1
                ]
            },
            {
                "Effect": "Allow",
                "Action": [
                    "s3:ListBucket",
                    "s3:GetBucketLocation",
                    "s3:ListBucketMultipartUploads"
                ],
                "Resource": [
                    "arn:aws:s3:::<bucket_name>" 2
                ]
            }
        ]
    }
    EOF
    1 2
    To grant access to a single S3 bucket, specify the bucket name. To grant access to all AWS S3 buckets, specify * instead of a bucket name:
    "Resource": [
        "arn:aws:s3:::*"
  5. Attach the EC2 EBS policy to velero:

    $ aws iam put-user-policy \
      --user-name velero \
      --policy-name velero-ebs \
      --policy-document file://velero-ec2-snapshot-policy.json
  6. Attach the AWS S3 policy to velero:

    $ aws iam put-user-policy \
      --user-name velero \
      --policy-name velero-s3 \
      --policy-document file://velero-s3-policy.json
  7. Create an access key for velero:

    $ aws iam create-access-key --user-name velero
    {
      "AccessKey": {
            "UserName": "velero",
            "Status": "Active",
            "CreateDate": "2017-07-31T22:24:41.576Z",
            "SecretAccessKey": <AWS_SECRET_ACCESS_KEY>, 1
            "AccessKeyId": <AWS_ACCESS_KEY_ID> 2
        }
    }
    1 2
    Record the AWS_SECRET_ACCESS_KEY and the AWS_ACCESS_KEY_ID for adding the AWS repository to the CAM web console.

1.5.4. Configuring a Google Cloud Provider storage bucket as a replication repository

You can configure a Google Cloud Provider (GCP) storage bucket as a replication repository.

Prerequisites

  • The GCP storage bucket must be accessible to the source and target clusters.
  • You must have gsutil installed.
  • If you are using the snapshot copy method:

    • The source and target clusters must be in the same region.
    • The source and target clusters must have the same storage class.
    • The storage class must be compatible with snapshots.

Procedure

  1. Run gsutil init to log in:

    $ gsutil init
    Welcome! This command will take you through the configuration of gcloud.
    
    Your current configuration has been set to: [default]
    
    To continue, you must login. Would you like to login (Y/n)?
  2. Set the BUCKET variable:

    $ BUCKET=<bucket_name> 1
    1
    Specify your bucket name.
  3. Create a storage bucket:

    $ gsutil mb gs://$BUCKET/
  4. Set the PROJECT_ID variable to your active project:

    $ PROJECT_ID=$(gcloud config get-value project)
  5. Create a velero service account:

    $ gcloud iam service-accounts create velero \
        --display-name "Velero Storage"
  6. Set the SERVICE_ACCOUNT_EMAIL variable to the service account’s email address:

    $ SERVICE_ACCOUNT_EMAIL=$(gcloud iam service-accounts list \
      --filter="displayName:Velero Storage" \
      --format 'value(email)')
  7. Grant permissions to the service account:

    $ ROLE_PERMISSIONS=(
        compute.disks.get
        compute.disks.create
        compute.disks.createSnapshot
        compute.snapshots.get
        compute.snapshots.create
        compute.snapshots.useReadOnly
        compute.snapshots.delete
        compute.zones.get
    )
    
    gcloud iam roles create velero.server \
        --project $PROJECT_ID \
        --title "Velero Server" \
        --permissions "$(IFS=","; echo "${ROLE_PERMISSIONS[*]}")"
    
    gcloud projects add-iam-policy-binding $PROJECT_ID \
        --member serviceAccount:$SERVICE_ACCOUNT_EMAIL \
        --role projects/$PROJECT_ID/roles/velero.server
    
    gsutil iam ch serviceAccount:$SERVICE_ACCOUNT_EMAIL:objectAdmin gs://${BUCKET}
  8. Save the service account’s keys to the credentials-velero file in the current directory:

    $ gcloud iam service-accounts keys create credentials-velero \
      --iam-account $SERVICE_ACCOUNT_EMAIL

1.5.5. Configuring a Microsoft Azure Blob storage container as a replication repository

You can configure a Microsoft Azure Blob storage container as a replication repository.

Prerequisites

  • You must have an Azure storage account.
  • You must have the Azure CLI installed.
  • The Azure Blob storage container must be accessible to the source and target clusters.
  • If you are using the snapshot copy method:

    • The source and target clusters must be in the same region.
    • The source and target clusters must have the same storage class.
    • The storage class must be compatible with snapshots.

Procedure

  1. Set the AZURE_RESOURCE_GROUP variable:

    $ AZURE_RESOURCE_GROUP=Velero_Backups
  2. Create an Azure resource group:

    $ az group create -n $AZURE_RESOURCE_GROUP --location <CentralUS> 1
    1
    Specify your location.
  3. Set the AZURE_STORAGE_ACCOUNT_ID variable:

    $ AZURE_STORAGE_ACCOUNT_ID=velerobackups
  4. Create an Azure storage account:

    $ az storage account create \
      --name $AZURE_STORAGE_ACCOUNT_ID \
      --resource-group $AZURE_RESOURCE_GROUP \
      --sku Standard_GRS \
      --encryption-services blob \
      --https-only true \
      --kind BlobStorage \
      --access-tier Hot
  5. Set the BLOB_CONTAINER variable:

    $ BLOB_CONTAINER=velero
  6. Create an Azure Blob storage container:

    $ az storage container create \
      -n $BLOB_CONTAINER \
      --public-access off \
      --account-name $AZURE_STORAGE_ACCOUNT_ID
  7. Create a service principal and credentials for velero:

    $ AZURE_SUBSCRIPTION_ID=`az account list --query '[?isDefault].id' -o tsv`
    $ AZURE_TENANT_ID=`az account list --query '[?isDefault].tenantId' -o tsv`
    $ AZURE_CLIENT_SECRET=`az ad sp create-for-rbac --name "velero" --role "Contributor" --query 'password' -o tsv`
    $ AZURE_CLIENT_ID=`az ad sp list --display-name "velero" --query '[0].appId' -o tsv`
  8. Save the service principal’s credentials in the credentials-velero file:

    $ cat << EOF  > ./credentials-velero
    AZURE_SUBSCRIPTION_ID=${AZURE_SUBSCRIPTION_ID}
    AZURE_TENANT_ID=${AZURE_TENANT_ID}
    AZURE_CLIENT_ID=${AZURE_CLIENT_ID}
    AZURE_CLIENT_SECRET=${AZURE_CLIENT_SECRET}
    AZURE_RESOURCE_GROUP=${AZURE_RESOURCE_GROUP}
    AZURE_CLOUD_NAME=AzurePublicCloud
    EOF

1.6. Migrating applications with the CAM web console

You can migrate application workloads by adding your clusters and replication repository to the CAM web console. Then, you can create and run a migration plan.

If your cluster or replication repository are secured with self-signed certificates, you can create a CA certificate bundle file or disable SSL verification.

1.6.1. Creating a CA certificate bundle file

If you use a self-signed certificate to secure a cluster or a replication repository, certificate verification might fail with the following error message: Certificate signed by unknown authority.

You can create a custom CA certificate bundle file and upload it in the CAM web console when you add a cluster or a replication repository.

Procedure

Download a CA certificate from a remote endpoint and save it as a CA bundle file:

$ echo -n | openssl s_client -connect <host_FQDN>:<port> \ 1
  | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > <ca_bundle.cert> 2
1
Specify the host FQDN and port of the endpoint, for example, api.my-cluster.example.com:6443.
2
Specify the name of the CA bundle file.

1.6.2. Adding a cluster to the CAM web console

You can add a cluster to the CAM web console.

Prerequisites

If you are using Azure snapshots to copy data:

  • You must provide the Azure resource group name when you add the source cluster.
  • The source and target clusters must be in the same Azure resource group and in the same location.

Procedure

  1. Log in to the cluster.
  2. Obtain the service account token:

    $ oc sa get-token mig -n openshift-migration
    eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJtaWciLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlY3JldC5uYW1lIjoibWlnLXRva2VuLWs4dDJyIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6Im1pZyIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50LnVpZCI6ImE1YjFiYWMwLWMxYmYtMTFlOS05Y2NiLTAyOWRmODYwYjMwOCIsInN1YiI6InN5c3RlbTpzZXJ2aWNlYWNjb3VudDptaWc6bWlnIn0.xqeeAINK7UXpdRqAtOj70qhBJPeMwmgLomV9iFxr5RoqUgKchZRG2J2rkqmPm6vr7K-cm7ibD1IBpdQJCcVDuoHYsFgV4mp9vgOfn9osSDp2TGikwNz4Az95e81xnjVUmzh-NjDsEpw71DH92iHV_xt2sTwtzftS49LpPW2LjrV0evtNBP_t_RfskdArt5VSv25eORl7zScqfe1CiMkcVbf2UqACQjo3LbkpfN26HAioO2oH0ECPiRzT0Xyh-KwFutJLS9Xgghyw-LD9kPKcE_xbbJ9Y4Rqajh7WdPYuB0Jd9DPVrslmzK-F6cgHHYoZEv0SvLQi-PO0rpDrcjOEQQ
  3. Log in to the CAM web console.
  4. In the Clusters section, click Add cluster.
  5. Fill in the following fields:

    • Cluster name: May contain lower-case letters (a-z) and numbers (0-9). Must not contain spaces or international characters.
    • Url: URL of the cluster’s API server, for example, https://<master1.example.com>:8443.
    • Service account token: String that you obtained from the source cluster.
    • Azure cluster: Optional. Select it if you are using Azure snapshots to copy your data.
    • Azure resource group: This field appears if Azure cluster is checked.
    • If you use a custom CA bundle, click Browse and browse to the CA bundle file.
  6. Click Add cluster.

    The cluster appears in the Clusters section.

1.6.3. Adding a replication repository to the CAM web console

You can add an object storage bucket as a replication repository to the CAM web console.

Prerequisites

  • You must configure an object storage bucket for migrating the data.

Procedure

  1. Log in to the CAM web console.
  2. In the Replication repositories section, click Add repository.
  3. Select a Storage provider type and fill in the following fields:

    • AWS for AWS S3, MCG, and generic S3 providers:

      • Replication repository name: Specify the replication repository name in the CAM web console.
      • S3 bucket name: Specify the name of the S3 bucket you created.
      • S3 bucket region: Specify the S3 bucket region. Required for AWS S3. Optional for other S3 providers.
      • S3 endpoint: Specify the URL of the S3 service, not the bucket, for example, https://<s3-storage.apps.cluster.com>. Required for a generic S3 provider. You must use the https:// prefix.
      • S3 provider access key: Specify the <AWS_SECRET_ACCESS_KEY> for AWS or the S3 provider access key for MCG.
      • S3 provider secret access key: Specify the <AWS_ACCESS_KEY_ID> for AWS or the S3 provider secret access key for MCG.
      • Require SSL verification: Clear this check box if you are using a generic S3 provider.
      • If you use a custom CA bundle, click Browse and browse to the Base64-encoded CA bundle file.
    • GCP:

      • Replication repository name: Specify the replication repository name in the CAM web console.
      • GCP bucket name: Specify the name of the GCP bucket.
      • GCP credential JSON blob: Specify the string in the credentials-velero file.
    • Azure:

      • Replication repository name: Specify the replication repository name in the CAM web console.
      • Azure resource group: Specify the resource group of the Azure Blob storage.
      • Azure storage account name: Specify the Azure Blob storage account name.
      • Azure credentials - INI file contents: Specify the string in the credentials-velero file.
  4. Click Add repository and wait for connection validation.
  5. Click Close.

    The new repository appears in the Replication repositories section.

1.6.4. Changing migration plan limits for large migrations

You can change the migration plan limits for large migrations.

Important

Changes should first be tested in your environment to avoid a failed migration.

A single migration plan has the following default limits:

  • 10 namespaces

    If this limit is exceeded, the CAM web console displays a Namespace limit exceeded error and you cannot create a migration plan.

  • 100 Pods

    If the Pod limit is exceeded, the CAM web console displays a warning message similar to the following example: Plan has been validated with warning condition(s). See warning message. Pod limit: 100 exceeded, found: 104.

  • 100 persistent volumes

    If the persistent volume limit is exceeded, the CAM web console displays a similar warning message.

Procedure

  1. Edit the Migration controller CR:

    $ oc get migrationcontroller -n openshift-migration
    NAME AGE
    migration-controller 5d19h
    
    $ oc edit migrationcontroller -n openshift-migration
  2. Update the following parameters:

    [...]
    migration_controller: true
    
    # This configuration is loaded into mig-controller, and should be set on the
    # cluster where `migration_controller: true`
    mig_pv_limit: 100
    mig_pod_limit: 100
    mig_namespace_limit: 10
    [...]

1.6.5. Creating a migration plan in the CAM web console

You can create a migration plan in the CAM web console.

Prerequisites

  • The CAM web console must contain the following:

    • Source cluster
    • Target cluster, which is added automatically during the CAM tool installation
    • Replication repository
  • If you use snapshots to copy data, the source and target clusters must be running on the same cloud provider (AWS, GCP, or Azure) and in the same region.

Procedure

  1. Log in to the CAM web console.
  2. In the Plans section, click Add plan.
  3. Enter the Plan name and click Next.

    The Plan name can contain up to 253 lower-case alphanumeric characters (a-z, 0-9). It must not contain spaces or underscores (_).

  4. Select a Source cluster.
  5. Select a Target cluster.
  6. Select a Replication repository.
  7. Select the projects to be migrated and click Next.
  8. Select Copy or Move for the PVs:

    • Copy copies the data in a source cluster’s PV to the replication repository and then restores it on a newly created PV, with similar characteristics, in the target cluster.

      Optional: You can verify data copied with the filesystem method by selecting Verify copy. This option, which generates a checksum for each source file and checks it after restoration, significantly reduces performance.

    • Move unmounts a remote volume (for example, NFS) from the source cluster, creates a PV resource on the target cluster pointing to the remote volume, and then mounts the remote volume on the target cluster. Applications running on the target cluster use the same remote volume that the source cluster was using. The remote volume must be accessible to the source and target clusters.
  9. Click Next.
  10. Select a Copy method for the PVs:

    • Snapshot backs up and restores the disk using the cloud provider’s snapshot functionality. It is significantly faster than Filesystem.

      Note

      The storage and clusters must be in the same region and the storage class must be compatible.

    • Filesystem copies the data files from the source disk to a newly created target disk.
  11. Select a Storage class for the PVs.

    If you selected the Filesystem copy method, you can change the storage class during migration, for example, from Red Hat Gluster Storage or NFS storage to Red Hat Ceph Storage.

  12. Click Next.
  13. If you want to add a migration hook, click Add Hook and perform the following steps:

    1. Specify the name of the hook.
    2. Select Ansible playbook to use your own playbook or Custom container image for a hook written in another language.
    3. Click Browse to upload the playbook.
    4. Optional: If you are not using the default Ansible runtime image, specify your custom Ansible image.
    5. Specify the cluster on which you want the hook to run.
    6. Specify the service account name.
    7. Specify the namespace.
    8. Select the migration step at which you want the hook to run:

      • PreBackup: Before backup tasks are started on the source cluster
      • PostBackup: After backup tasks are complete on the source cluster
      • PreRestore: Before restore tasks are started on the target cluster
      • PostRestore: After restore tasks are complete on the target cluster
  14. Click Add.

    You can add up to four hooks to a migration plan, assigning each hook to a different migration step.

  15. Click Finish.
  16. Click Close.

    The migration plan appears in the Plans section.

1.6.6. Running a migration plan in the CAM web console

You can stage or migrate applications and data with the migration plan you created in the CAM web console.

Prerequisites

The CAM web console must contain the following:

  • Source cluster
  • Target cluster, which is added automatically during the CAM tool installation
  • Replication repository
  • Valid migration plan

Procedure

  1. Log in to the CAM web console on the target cluster.
  2. Select a migration plan.
  3. Click Stage to copy data from the source cluster to the target cluster without stopping the application.

    You can run Stage multiple times to reduce the actual migration time.

  4. When you are ready to migrate the application workload, click Migrate.

    Migrate stops the application workload on the source cluster and recreates its resources on the target cluster.

  5. Optional: In the Migrate window, you can select Do not stop applications on the source cluster during migration.
  6. Click Migrate.
  7. When the migration is complete, verify that the application migrated successfully in the OpenShift Container Platform web console:

    1. Click HomeProjects.
    2. Click the migrated project to view its status.
    3. In the Routes section, click Location to verify that the application is functioning, if applicable.
    4. Click WorkloadsPods to verify that the Pods are running in the migrated namespace.
    5. Click StoragePersistent volumes to verify that the migrated persistent volume is correctly provisioned.

1.7. Migrating control plane settings with the Control Plane Migration Assistant (CPMA)

1.7.1. Understanding the Control Plane Migration Assistant

The Control Plane Migration Assistant (CPMA) is a CLI-based tool that assists you in migrating the control plane from OpenShift Container Platform 3.7 (or later) to OpenShift Container Platform 4.4. The CPMA processes the OpenShift Container Platform 3 configuration files and generates Custom Resource (CR) manifest files, which are consumed by OpenShift Container Platform 4.4 Operators.

Because OpenShift Container Platform 3 and 4 have significant configuration differences, not all parameters are processed. The CPMA can generate a report that describes whether features are supported fully, partially, or not at all.

Configuration files

CPMA uses the Kubernetes and OpenShift Container Platform APIs to access the following configuration files on an OpenShift Container Platform 3 cluster:

  • Master configuration file (default: /etc/origin/master/master-config.yaml)
  • CRI-O configuration file (default: /etc/crio/crio.conf)
  • etcd configuration file (default: /etc/etcd/etcd.conf)
  • Image registries file (default: /etc/containers/registries.conf)
  • Dependent configuration files:

    • Password files (for example, HTPasswd)
    • ConfigMaps
    • Secrets

CR Manifests

CPMA generates CR manifests for the following configurations:

  • API server CA certificate: 100_CPMA-cluster-config-APISecret.yaml

    Note

    If you are using an unsigned API server CA certificate, you must add the certificate manually to the target cluster.

  • CRI-O: 100_CPMA-crio-config.yaml
  • Cluster resource quota: 100_CPMA-cluster-quota-resource-x.yaml
  • Project resource quota: 100_CPMA-resource-quota-x.yaml
  • Portable image registry (/etc/registries/registries.conf) and portable image policy (etc/origin/master/master-config.yam): 100_CPMA-cluster-config-image.yaml
  • OAuth providers: 100_CPMA-cluster-config-oauth.yaml
  • Project configuration: 100_CPMA-cluster-config-project.yaml
  • Scheduler: 100_CPMA-cluster-config-scheduler.yaml
  • SDN: 100_CPMA-cluster-config-sdn.yaml

1.7.2. Installing the Control Plane Migration Assistant

You can download the Control Plane Migration Assistant (CPMA) binary file from the Red Hat Customer Portal and install it on Linux, MacOSX, or Windows operating systems.

Procedure

  1. In the Red Hat Customer Portal, navigate to DownloadsRed Hat OpenShift Container Platform.
  2. On the Download Red Hat OpenShift Container Platform page, select Red Hat OpenShift Container Platform from the Product Variant list.
  3. Select CPMA 1.0 for RHEL 7 from the Version list. This binary works on RHEL 7 and RHEL 8.
  4. Click Download Now to download cpma for Linux or MacOSX or cpma.exe for Windows.
  5. Save the file in a directory defined as $PATH for Linux or MacOSX or %PATH% for Windows.
  6. For Linux, make the file executable:

    $ sudo chmod +x cpma

1.7.3. Using the Control Plane Migration Assistant

The Control Plane Migration Assistant (CPMA) generates CR manifests, which are consumed by OpenShift Container Platform 4.4 Operators, and a report that indicates which OpenShift Container Platform 3 features are supported fully, partially, or not at all.

The CPMA can run in remote mode, retrieving the configuration files from the source cluster using SSH, or in local mode, using local copies of the source cluster’s configuration files.

Prerequisites

  • The source cluster must be OpenShift Container Platform 3.7 or later.
  • The source cluster must be updated to the latest synchronous release.
  • An environment health check must be run on the source cluster to confirm that there are no diagnostic errors or warnings.
  • The CPMA binary must be executable.
  • You must have cluster-admin privileges for the source cluster.

Procedure

  1. Log in to the OpenShift Container Platform 3 cluster:

    $ oc login https://<master1.example.com> 1
    1
    OpenShift Container Platform 3 master node. You must be logged in to the cluster to receive a token for the Kubernetes and OpenShift Container Platform APIs.
  2. Run the CPMA. Each prompt requires you to provide input, as in the following example:

    $ cpma --manifests=false 1
    ? Do you wish to save configuration for future use? true
    ? What will be the source for OCP3 config files? Remote host 2
    ? Path to crio config file /etc/crio/crio.conf
    ? Path to etcd config file /etc/etcd/etcd.conf
    ? Path to master config file /etc/origin/master/master-config.yaml
    ? Path to node config file /etc/origin/node/node-config.yaml
    ? Path to registries config file /etc/containers/registries.conf
    ? Do wish to find source cluster using KUBECONFIG or prompt it? KUBECONFIG
    ? Select cluster obtained from KUBECONFIG contexts master1-example-com:443
    ? Select master node master1.example.com
    ? SSH login root 3
    ? SSH Port 22
    ? Path to private SSH key /home/user/.ssh/openshift_key
    ? Path to application data, skip to use current directory .
    INFO[29 Aug 19 00:07 UTC] Starting manifest and report generation
    INFO[29 Aug 19 00:07 UTC] Transform:Starting for - API
    INFO[29 Aug 19 00:07 UTC] APITransform::Extract
    INFO[29 Aug 19 00:07 UTC] APITransform::Transform:Reports
    INFO[29 Aug 19 00:07 UTC] Transform:Starting for - Cluster
    INFO[29 Aug 19 00:08 UTC] ClusterTransform::Transform:Reports
    INFO[29 Aug 19 00:08 UTC] ClusterReport::ReportQuotas
    INFO[29 Aug 19 00:08 UTC] ClusterReport::ReportPVs
    INFO[29 Aug 19 00:08 UTC] ClusterReport::ReportNamespaces
    INFO[29 Aug 19 00:08 UTC] ClusterReport::ReportNodes
    INFO[29 Aug 19 00:08 UTC] ClusterReport::ReportRBAC
    INFO[29 Aug 19 00:08 UTC] ClusterReport::ReportStorageClasses
    INFO[29 Aug 19 00:08 UTC] Transform:Starting for - Crio
    INFO[29 Aug 19 00:08 UTC] CrioTransform::Extract
    WARN[29 Aug 19 00:08 UTC] Skipping Crio: No configuration file available
    INFO[29 Aug 19 00:08 UTC] Transform:Starting for - Docker
    INFO[29 Aug 19 00:08 UTC] DockerTransform::Extract
    INFO[29 Aug 19 00:08 UTC] DockerTransform::Transform:Reports
    INFO[29 Aug 19 00:08 UTC] Transform:Starting for - ETCD
    INFO[29 Aug 19 00:08 UTC] ETCDTransform::Extract
    INFO[29 Aug 19 00:08 UTC] ETCDTransform::Transform:Reports
    INFO[29 Aug 19 00:08 UTC] Transform:Starting for - OAuth
    INFO[29 Aug 19 00:08 UTC] OAuthTransform::Extract
    INFO[29 Aug 19 00:08 UTC] OAuthTransform::Transform:Reports
    INFO[29 Aug 19 00:08 UTC] Transform:Starting for - SDN
    INFO[29 Aug 19 00:08 UTC] SDNTransform::Extract
    INFO[29 Aug 19 00:08 UTC] SDNTransform::Transform:Reports
    INFO[29 Aug 19 00:08 UTC] Transform:Starting for - Image
    INFO[29 Aug 19 00:08 UTC] ImageTransform::Extract
    INFO[29 Aug 19 00:08 UTC] ImageTransform::Transform:Reports
    INFO[29 Aug 19 00:08 UTC] Transform:Starting for - Project
    INFO[29 Aug 19 00:08 UTC] ProjectTransform::Extract
    INFO[29 Aug 19 00:08 UTC] ProjectTransform::Transform:Reports
    INFO[29 Aug 19 00:08 UTC] Flushing reports to disk
    INFO[29 Aug 19 00:08 UTC] Report:Added: report.json
    INFO[29 Aug 19 00:08 UTC] Report:Added: report.html
    INFO[29 Aug 19 00:08 UTC] Successfully finished transformations
    1
    --manifests=false: Without generating CR manifests
    2
    Remote host: Remote mode
    3
    SSH login: The SSH user must have sudo permissions on the OpenShift Container Platform 3 cluster in order to access the configuration files.

    The CPMA creates the following files and directory in the current directory if you did not specify an output directory:

    • cpma.yaml file: Configuration options that you provided when you ran the CPMA
    • master1.example.com/: Configuration files from the master node
    • report.json: JSON-encoded report
    • report.html: HTML-encoded report
  3. Open the report.html file in a browser to view the CPMA report.
  4. If you generate CR manifests, apply the CR manifests to the OpenShift Container Platform 4.4 cluster, as in the following example:

    $ oc apply -f 100_CPMA-cluster-config-secret-htpasswd-secret.yaml

1.8. Troubleshooting

You can view the migration Custom Resources (CRs) and download logs to troubleshoot a failed migration.

If the application was stopped during the failed migration, you must roll it back manually in order to prevent data corruption.

Note

Manual rollback is not required if the application was not stopped during migration, because the original application is still running on the source cluster.

1.8.1. Viewing migration Custom Resources

The Cluster Application Migration (CAM) tool creates the following Custom Resources (CRs):

migration architecture diagram

20 MigCluster (configuration, CAM cluster): Cluster definition

20 MigStorage (configuration, CAM cluster): Storage definition

20 MigPlan (configuration, CAM cluster): Migration plan

The MigPlan CR describes the source and target clusters, repository, and namespace(s) being migrated. It is associated with 0, 1, or many MigMigration CRs.

Note

Deleting a MigPlan CR deletes the associated MigMigration CRs.

20 BackupStorageLocation (configuration, CAM cluster): Location of Velero backup objects

20 VolumeSnapshotLocation (configuration, CAM cluster): Location of Velero volume snapshots

20 MigMigration (action, CAM cluster): Migration, created during migration

A MigMigration CR is created every time you stage or migrate data. Each MigMigration CR is associated with a MigPlan CR.

20 Backup (action, source cluster): When you run a migration plan, the MigMigration CR creates two Velero backup CRs on each source cluster:

  • Backup CR #1 for Kubernetes objects
  • Backup CR #2 for PV data

20 Restore (action, target cluster): When you run a migration plan, the MigMigration CR creates two Velero restore CRs on the target cluster:

  • Restore CR #1 (using Backup CR #2) for PV data
  • Restore CR #2 (using Backup CR #1) for Kubernetes objects

Procedure

  1. Get the CR name:

    $ oc get <migration_cr> -n openshift-migration 1
    1
    Specify the migration CR, for example, migmigration.

    The output is similar to the following:

    NAME                                   AGE
    88435fe0-c9f8-11e9-85e6-5d593ce65e10   6m42s
  2. View the CR:

    $ oc describe <migration_cr> <88435fe0-c9f8-11e9-85e6-5d593ce65e10> -n openshift-migration

    The output is similar to the following examples.

MigMigration example

name:         88435fe0-c9f8-11e9-85e6-5d593ce65e10
namespace:    openshift-migration
labels:       <none>
annotations:  touch: 3b48b543-b53e-4e44-9d34-33563f0f8147
apiVersion:  migration.openshift.io/v1alpha1
kind:         MigMigration
metadata:
  creationTimestamp:  2019-08-29T01:01:29Z
  generation:          20
  resourceVersion:    88179
  selfLink:           /apis/migration.openshift.io/v1alpha1/namespaces/openshift-migration/migmigrations/88435fe0-c9f8-11e9-85e6-5d593ce65e10
  uid:                 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
spec:
  migPlanRef:
    name:        socks-shop-mig-plan
    namespace:   openshift-migration
  quiescePods:  true
  stage:         false
status:
  conditions:
    category:              Advisory
    durable:               True
    lastTransitionTime:  2019-08-29T01:03:40Z
    message:               The migration has completed successfully.
    reason:                Completed
    status:                True
    type:                  Succeeded
  phase:                   Completed
  startTimestamp:         2019-08-29T01:01:29Z
events:                    <none>

Velero backup CR #2 example (PV data)

apiVersion: velero.io/v1
kind: Backup
metadata:
  annotations:
    openshift.io/migrate-copy-phase: final
    openshift.io/migrate-quiesce-pods: "true"
    openshift.io/migration-registry: 172.30.105.179:5000
    openshift.io/migration-registry-dir: /socks-shop-mig-plan-registry-44dd3bd5-c9f8-11e9-95ad-0205fe66cbb6
  creationTimestamp: "2019-08-29T01:03:15Z"
  generateName: 88435fe0-c9f8-11e9-85e6-5d593ce65e10-
  generation: 1
  labels:
    app.kubernetes.io/part-of: migration
    migmigration: 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
    migration-stage-backup: 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
    velero.io/storage-location: myrepo-vpzq9
  name: 88435fe0-c9f8-11e9-85e6-5d593ce65e10-59gb7
  namespace: openshift-migration
  resourceVersion: "87313"
  selfLink: /apis/velero.io/v1/namespaces/openshift-migration/backups/88435fe0-c9f8-11e9-85e6-5d593ce65e10-59gb7
  uid: c80dbbc0-c9f8-11e9-95ad-0205fe66cbb6
spec:
  excludedNamespaces: []
  excludedResources: []
  hooks:
    resources: []
  includeClusterResources: null
  includedNamespaces:
  - sock-shop
  includedResources:
  - persistentvolumes
  - persistentvolumeclaims
  - namespaces
  - imagestreams
  - imagestreamtags
  - secrets
  - configmaps
  - pods
  labelSelector:
    matchLabels:
      migration-included-stage-backup: 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
  storageLocation: myrepo-vpzq9
  ttl: 720h0m0s
  volumeSnapshotLocations:
  - myrepo-wv6fx
status:
  completionTimestamp: "2019-08-29T01:02:36Z"
  errors: 0
  expiration: "2019-09-28T01:02:35Z"
  phase: Completed
  startTimestamp: "2019-08-29T01:02:35Z"
  validationErrors: null
  version: 1
  volumeSnapshotsAttempted: 0
  volumeSnapshotsCompleted: 0
  warnings: 0

Velero restore CR #2 example (Kubernetes resources)

apiVersion: velero.io/v1
kind: Restore
metadata:
  annotations:
    openshift.io/migrate-copy-phase: final
    openshift.io/migrate-quiesce-pods: "true"
    openshift.io/migration-registry: 172.30.90.187:5000
    openshift.io/migration-registry-dir: /socks-shop-mig-plan-registry-36f54ca7-c925-11e9-825a-06fa9fb68c88
  creationTimestamp: "2019-08-28T00:09:49Z"
  generateName: e13a1b60-c927-11e9-9555-d129df7f3b96-
  generation: 3
  labels:
    app.kubernetes.io/part-of: migration
    migmigration: e18252c9-c927-11e9-825a-06fa9fb68c88
    migration-final-restore: e18252c9-c927-11e9-825a-06fa9fb68c88
  name: e13a1b60-c927-11e9-9555-d129df7f3b96-gb8nx
  namespace: openshift-migration
  resourceVersion: "82329"
  selfLink: /apis/velero.io/v1/namespaces/openshift-migration/restores/e13a1b60-c927-11e9-9555-d129df7f3b96-gb8nx
  uid: 26983ec0-c928-11e9-825a-06fa9fb68c88
spec:
  backupName: e13a1b60-c927-11e9-9555-d129df7f3b96-sz24f
  excludedNamespaces: null
  excludedResources:
  - nodes
  - events
  - events.events.k8s.io
  - backups.velero.io
  - restores.velero.io
  - resticrepositories.velero.io
  includedNamespaces: null
  includedResources: null
  namespaceMapping: null
  restorePVs: true
status:
  errors: 0
  failureReason: ""
  phase: Completed
  validationErrors: null
  warnings: 15

1.8.2. Downloading migration logs

You can download the Velero, Restic, and Migration controller logs in the CAM web console to troubleshoot a failed migration.

Procedure

  1. Log in to the CAM console.
  2. Click Plans to view the list of migration plans.
  3. Click the Options menu kebab of a specific migration plan and select Logs.
  4. Click Download Logs to download the logs of the Migration controller, Velero, and Restic for all clusters.
  5. To download a specific log:

    1. Specify the log options:

      • Cluster: Select the source, target, or CAM host cluster.
      • Log source: Select Velero, Restic, or Controller.
      • Pod source: Select the Pod name, for example, controller-manager-78c469849c-v6wcf

        The selected log is displayed.

        You can clear the log selection settings by changing your selection.

    2. Click Download Selected to download the selected log.

Optionally, you can access the logs by using the CLI, as in the following example:

$ oc get pods -n openshift-migration | grep controller
controller-manager-78c469849c-v6wcf           1/1     Running     0          4h49m

$ oc logs controller-manager-78c469849c-v6wcf -f -n openshift-migration

1.8.3. Updating deprecated API GroupVersionKinds

In OpenShift Container Platform 4.4, some API GroupVersionKinds (GVKs) that are used by OpenShift Container Platform 3.x are deprecated.

If your source cluster uses deprecated GVKs, the following warning is displayed when you create a migration plan: Some namespaces contain GVKs incompatible with destination cluster. You can click See details to view the namespace and the incompatible GVKs.

Note

This warning does not block the migration.

During migration, the deprecated GVKs are saved in the Velero Backup Custom Resource (CR) #1 for Kubernetes objects. You can download the Backup CR, extract the deprecated GVK yaml files, and update them with the oc convert command. Then you create the updated GVKs on the target cluster.

Procedure

  1. Run the migration plan.
  2. View the MigPlan CR:

    $ oc describe migplan <migplan_name> -n openshift-migration 1
    1
    Specify the name of the migration plan.

    The output is similar to the following:

    metadata:
      [...]
      uid: 79509e05-61d6-11e9-bc55-02ce4781844a 1
    status:
      [...]
      conditions:
      - category: Warn
        lastTransitionTime: 2020-04-30T17:16:23Z
        message: 'Some namespaces contain GVKs incompatible with destination cluster.
          See: `incompatibleNamespaces` for details'
        status: "True"
        type: GVKsIncompatible
      incompatibleNamespaces:
      - gvks:
        - group: batch
          kind: cronjobs 2
          version: v2alpha1
        - group: batch
          kind: scheduledjobs 3
          version: v2alpha1
    1
    Record the MigPlan UID.
    2 3
    Record the deprecated GVKs.
  3. Get the MigMigration name associated with the MigPlan UID:

    $ oc get migmigration -o json | jq -r '.items[] | select(.metadata.ownerReferences[].uid=="<migplan_uid>") | .metadata.name' 1
    1
    Specify the MigPlan UID.
  4. Get the MigMigration UID associated with the MigMigration name:

    $ oc get migmigration <migmigration_name> -o jsonpath='{.metadata.uid}' 1
    1
    Specify the MigMigration name.
  5. Get the Velero Backup name associated with the MigMigration UID:

    $ oc get backup.velero.io --selector migration-initial-backup="<migmigration_uid>" -o jsonpath={.items[*].metadata.name} 1
    1
    Specify the MigMigration UID.
  6. Download the contents of the Velero Backup to your local machine:

    • For AWS S3:

      $ aws s3 cp s3://<bucket_name>/velero/backups/<backup_name> <backup_local_dir> --recursive 1
      1
      Specify the bucket, backup name, and your local backup directory name.
    • For GCP:

      $ gsutil cp gs://<bucket_name>/velero/backups/<backup_name> <backup_local_dir> --recursive 1
      1
      Specify the bucket, backup name, and your local backup directory name.
    • For Azure:

      $ azcopy copy 'https://velerobackups.blob.core.windows.net/velero/backups/<backup_name>' '<backup_local_dir>' --recursive 1
      1
      Specify the backup name and your local backup directory name.
  7. Extract the Velero Backup archive file:

    $ tar -xfv <backup_local_dir>/<backup_name>.tar.gz -C <backup_local_dir>
  8. Run oc convert in offline mode on each deprecated GVK:

    $ oc convert <backup_local_dir>/resources/<gvk>.yaml 1
    1
    Specify the deprecated GVK.
  9. Create the converted GVK on the target cluster:

    $ oc create -f <gvk>.yaml 1
    1
    Specify the converted GVK.

1.8.4. Error messages

1.8.4.1. Restic timeout error message in the Velero Pod log

If a migration fails because Restic times out, the following error appears in the Velero Pod log:

level=error msg="Error backing up item" backup=velero/monitoring error="timed out waiting for all PodVolumeBackups to complete" error.file="/go/src/github.com/heptio/velero/pkg/restic/backupper.go:165" error.function="github.com/heptio/velero/pkg/restic.(*backupper).BackupPodVolumes" group=v1

The default value of restic_timeout is one hour. You can increase this parameter for large migrations, keeping in mind that a higher value may delay the return of error messages.

Procedure

  1. In the OpenShift Container Platform web console, navigate to OperatorsInstalled Operators.
  2. Click Cluster Application Migration Operator.
  3. In the MigrationController tab, click migration-controller.
  4. In the YAML tab, update the following parameter value:

    spec:
      restic_timeout: 1h 1
    1
    Valid units are h (hours), m (minutes), and s (seconds), for example, 3h30m15s.
  5. Click Save.

1.8.4.2. ResticVerifyErrors in the MigMigration Custom Resource

If data verification fails when migrating a PV with the filesystem data copy method, the following error appears in the MigMigration Custom Resource (CR):

status:
  conditions:
  - category: Warn
    durable: true
    lastTransitionTime: 2020-04-16T20:35:16Z
    message: There were verify errors found in 1 Restic volume restores. See restore `<registry-example-migration-rvwcm>`
      for details 1
    status: "True"
    type: ResticVerifyErrors 2
1
The error message identifies the Restore CR name.
2
ResticErrors also appears. ResticErrors is a general error warning that includes verification errors.
Note

A data verification error does not cause the migration process to fail.

You can check the target cluster’s Restore CR to identify the source of the data verification error.

Procedure

  1. Log in to the target cluster.
  2. View the Restore CR:

    $ oc describe <registry-example-migration-rvwcm> -n openshift-migration

    The output identifies the PV with PodVolumeRestore errors:

    status:
      phase: Completed
      podVolumeRestoreErrors:
      - kind: PodVolumeRestore
        name: <registry-example-migration-rvwcm-98t49>
        namespace: openshift-migration
      podVolumeRestoreResticErrors:
      - kind: PodVolumeRestore
        name: <registry-example-migration-rvwcm-98t49>
        namespace: openshift-migration
  3. View the PodVolumeRestore CR:

    $ oc describe <migration-example-rvwcm-98t49>

    The output identifies the Restic Pod that logged the errors:

      completionTimestamp: 2020-05-01T20:49:12Z
      errors: 1
      resticErrors: 1
    ...
      resticPod: <restic-nr2v5>
  4. View the Restic Pod log:

    $ oc logs -f restic-nr2v5

1.8.5. Manually rolling back a migration

If your application was stopped during a failed migration, you must roll it back manually in order to prevent data corruption in the PV.

This procedure is not required if the application was not stopped during migration, because the original application is still running on the source cluster.

Procedure

  1. On the target cluster, switch to the migrated project:

    $ oc project <project>
  2. Get the deployed resources:

    $ oc get all
  3. Delete the deployed resources to ensure that the application is not running on the target cluster and accessing data on the PVC:

    $ oc delete <resource_type>
  4. To stop a DaemonSet without deleting it, update the nodeSelector in the YAML file:

    apiVersion: apps/v1
    kind: DaemonSet
    metadata:
      name: hello-daemonset
    spec:
      selector:
          matchLabels:
            name: hello-daemonset
      template:
        metadata:
          labels:
            name: hello-daemonset
        spec:
          nodeSelector:
            role: worker 1
    1
    Specify a nodeSelector value that does not exist on any node.
  5. Update each PV’s reclaim policy so that unnecessary data is removed. During migration, the reclaim policy for bound PVs is Retain, to ensure that data is not lost when an application is removed from the source cluster. You can remove these PVs during rollback.

    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv0001
    spec:
      capacity:
        storage: 5Gi
      accessModes:
        - ReadWriteOnce
      persistentVolumeReclaimPolicy: Retain 1
      ...
    status:
      ...
    1
    Specify Recycle or Delete.
  6. On the source cluster, switch to the migrated project and get its deployed resources:

    $ oc project <project>
    $ oc get all
  7. Start one or more replicas of each deployed resource:

    $ oc scale --replicas=1 <resource_type>/<resource_name>
  8. Update the nodeSelector of a DaemonSet to its original value, if you changed it during the procedure.

1.8.6. Gathering data for a customer support case

If you open a customer support case, you can run the must-gather tool with the openshift-migration-must-gather-rhel8 image to collect information about your cluster and upload it to the Red Hat Customer Portal.

The openshift-migration-must-gather-rhel8 image collects logs and Custom Resource data that are not collected by the default must-gather image.

Procedure

  1. Navigate to the directory where you want to store the must-gather data.
  2. Run the oc adm must-gather command:

    $ oc adm must-gather --image=registry.redhat.io/rhcam-1-2/openshift-migration-must-gather-rhel8

    The must-gather tool collects the cluster information and stores it in a must-gather.local.<uid> directory.

  3. Remove authentication keys and other sensitive information from the must-gather data.
  4. Create an archive file containing the contents of the must-gather.local.<uid> directory:

    $ tar cvaf must-gather.tar.gz must-gather.local.<uid>/

    You can attach the compressed file to your customer support case on the Red Hat Customer Portal.

1.8.7. Known issues

This release has the following known issues:

  • During migration, the Cluster Application Migration (CAM) tool preserves the following namespace annotations:

    • openshift.io/sa.scc.mcs
    • openshift.io/sa.scc.supplemental-groups
    • openshift.io/sa.scc.uid-range

      These annotations preserve the UID range, ensuring that the containers retain their file system permissions on the target cluster. There is a risk that the migrated UIDs could duplicate UIDs within an existing or future namespace on the target cluster. (BZ#1748440)

  • If an AWS bucket is added to the CAM web console and then deleted, its status remains True because the MigStorage CR is not updated. (BZ#1738564)
  • Most cluster-scoped resources are not yet handled by the CAM tool. If your applications require cluster-scoped resources, you may have to create them manually on the target cluster.
  • If a migration fails, the migration plan does not retain custom PV settings for quiesced pods. You must manually roll back the migration, delete the migration plan, and create a new migration plan with your PV settings. (BZ#1784899)
  • If a large migration fails because Restic times out, you can increase the restic_timeout parameter value (default: 1h) in the Migration controller CR.
  • If you select the data verification option for PVs that are migrated with the filesystem copy method, performance is significantly slower. Velero generates a checksum for each file and checks it when the file is restored.
  • In the current release (CAM 1.2), you cannot migrate from OpenShift Container Platform 3.7 to 4.4 because certain API GroupVersionKinds (GVKs) that are used by the source cluster are deprecated. You can manually update the GVKs after migration. (BZ#1817251)

Chapter 2. Migrating OpenShift Container Platform 4.1 to 4.3

2.1. Migrating application workloads from OpenShift Container Platform 4.1 to 4.4

You can migrate application workloads from OpenShift Container Platform 4.1 to 4.4 with the Cluster Application Migration (CAM) tool. The CAM tool enables you to control the migration and to minimize application downtime.

The CAM tool’s web console and API, based on Kubernetes Custom Resources, enable you to migrate stateful and stateless application workloads at the granularity of a namespace.

2.1.1. Migration prerequisites

  • You must have cluster-admin privileges on all clusters.
  • The source and target clusters must have unrestricted network access to the replication repository.
  • The cluster on which the Migration controller is installed must have unrestricted access to the other clusters.
  • If your application uses images from the openshift namespace, the required versions of the images must be present on the target cluster.

    If the required images are not present, you must update the imagestreamtags references to use an available version that is compatible with your application. If the imagestreamtags cannot be updated, you can manually upload equivalent images to the application namespaces and update the applications to reference them.

    The following imagestreamtags have been removed from OpenShift Container Platform 4.2:

    • dotnet:1.0, dotnet:1.1, dotnet:2.0
    • dotnet-runtime:2.0
    • mariadb:10.1
    • mongodb:2.4, mongodb:2.6
    • mysql:5.5, mysql:5.6
    • nginx:1.8
    • nodejs:0.10, nodejs:4, nodejs:6
    • perl:5.16, perl:5.20
    • php:5.5, php:5.6
    • postgresql:9.2, postgresql:9.4, postgresql:9.5
    • python:3.3, python:3.4
    • ruby:2.0, ruby:2.2

      The following imagestreamtags have been removed from OpenShift Container Platform 4.4:

    • dotnet: 2.2
    • dotnet-runtime: 2.2
    • nginx: 1.12
    • nodejs: 8, 8-RHOAR, 10-SCL
    • perl:5.24
    • php: 7.0, 7.1
    • redis: 3.2

2.1.2. Understanding the Cluster Application Migration tool

The Cluster Application Migration (CAM) tool enables you to migrate Kubernetes resources, persistent volume data, and internal container images from an OpenShift Container Platform source cluster to an OpenShift Container Platform 4.4 target cluster, using the CAM web console or the Kubernetes API.

Migrating an application with the CAM web console involves the following steps:

  1. Install the Cluster Application Migration Operator on all clusters.

    Note

    The Cluster Application Migration Operator installs the CAM tool (CAM web console and Migration controller) on the target cluster by default. You can configure the Migration controller to install the CAM tool on another cluster. The cluster on which the CAM tool is installed is referred to as the CAM tool cluster.

  2. Configure the replication repository, an intermediate object storage that the CAM tool uses to migrate data.
  3. Add the source cluster to the CAM web console.
  4. Add the replication repository to the CAM web console.
  5. Create a migration plan, with one of the following data migration options:

    • Copy: The CAM tool copies the data from the source cluster to the replication repository, and from the replication repository to the target cluster.

      migration PV copy
    • Move: The CAM tool unmounts a remote volume (for example, NFS) from the source cluster, creates a PV resource on the target cluster pointing to the remote volume, and then mounts the remote volume on the target cluster. Applications running on the target cluster use the same remote volume that the source cluster was using. The remote volume must be accessible to the source and target clusters.

      Note

      Although the replication repository does not appear in this diagram, it is required for the actual migration.

      migration PV move
  6. Run the migration plan, with one of the following options:

    • Stage (optional) copies data to the target cluster without stopping the application.

      Staging can be run multiple times so that most of the data is copied to the target before migration. This minimizes the actual migration time and application downtime.

    • Migrate stops the application on the source cluster and recreates its resources on the target cluster. Optionally, you can migrate the workload without stopping the application.
OCP 3 to 4 App migration

2.1.3. Understanding migration hooks

You can use migration hooks to run Ansible playbooks at certain points during the migration. The hooks are added when you create a migration plan.

Note

If you do not want to use Ansible playbooks, you can create a custom container image and add it to a migration plan.

Migration hooks perform tasks such as customizing application quiescence, manually migrating unsupported data types, and updating applications after migration.

A single migration hook runs on a source or target cluster at one of the following migration steps:

  • PreBackup: Before backup tasks are started on the source cluster
  • PostBackup: After backup tasks are complete on the source cluster
  • PreRestore: Before restore tasks are started on the target cluster
  • PostRestore: After restore tasks are complete on the target cluster

    You can assign one hook to each migration step, up to a maximum of four hooks for a single migration plan.

The default hook-runner image is registry.redhat.io/rhcam-1-2/openshift-migration-hook-runner-rhel7. This image is based on Ansible Runner and includes python-openshift for Ansible Kubernetes resources and an updated oc binary. You can also create your own hook image with additional Ansible modules or tools.

The Ansible playbook is mounted on a hook container as a ConfigMap. The hook container runs as a Job on a cluster with a specified service account and namespace. The Job runs, even if the initial Pod is evicted or killed, until it reaches the default backoffLimit (6) or successful completion.

2.2. Deploying the Cluster Application Migration (CAM) tool

Deploying the Cluster Application Migration (CAM) tool requires installing the Cluster Application Migration Operator on the OpenShift Container Platform 4.1 source and OpenShift Container Platform 4.4 target clusters.

2.2.1. Installing the Cluster Application Migration Operator on an OpenShift Container Platform 4.1 source cluster

You can install the Cluster Application Migration Operator on an OpenShift Container Platform 4.1 source cluster with OLM.

Procedure

  1. In the OpenShift Container Platform web console, click CatalogOperatorHub.
  2. Use the Filter by keyword field (in this case, Migration) to find the Cluster Application Migration Operator.
  3. Select the Cluster Application Migration Operator and click Install.
  4. On the Create Operator Subscription page, select the openshift-migration namespace, and specify an approval strategy.
  5. Click Subscribe.

    On the Installed Operators page, the Cluster Application Migration Operator appears in the openshift-migration project with the status InstallSucceeded.

  6. Under Provided APIs, click View 12 more…​.
  7. Click Create NewMigrationController.
  8. Update the migration_controller and migration_ui parameters and add the deprecated_cors_configuration parameter to the spec stanza:

    spec:
      [...]
      migration_controller: false
      migration_ui: false
      [...]
      deprecated_cors_configuration: true
  9. Click Create.
  10. Click WorkloadsPods to verify that the Restic and Velero Pods are running.

2.2.2. Installing the Cluster Application Migration Operator on an OpenShift Container Platform 4.4 target cluster

You can install the Cluster Application Migration Operator on an OpenShift Container Platform 4.4 target cluster with OLM.

The Cluster Application Migration Operator installs the CAM tool on the target cluster by default. If you want to install the CAM tool on a different cluster, you must update the Migration controller configuration so that the Cluster Application Migration Operator does not install the CAM tool on this cluster.

Procedure

  1. In the OpenShift Container Platform web console, click OperatorsOperatorHub.
  2. Use the Filter by keyword field (in this case, Migration) to find the Cluster Application Migration Operator.
  3. Select the Cluster Application Migration Operator and click Install.
  4. On the Create Operator Subscription page, select the openshift-migration namespace, and specify an approval strategy.
  5. Click Subscribe.

    On the Installed Operators page, the Cluster Application Migration Operator appears in the openshift-migration project with the status InstallSucceeded.

  6. Under Provided APIs, click View 12 more…​.
  7. Click Create NewMigrationController.
  8. Click Create.
  9. Click WorkloadsPods to verify that the Controller Manager, Migration UI, Restic, and Velero Pods are running.

2.2.3. Launching the CAM web console

You can launch the CAM web console in a browser.

Procedure

  1. Log in to the OpenShift Container Platform cluster on which you have installed the CAM tool.
  2. Obtain the CAM web console URL by entering the following command:

    $ oc get -n openshift-migration route/migration -o go-template='https://{{ .spec.host }}'
    https://migration-openshift-migration.apps.<cluster>.openshift.com
  3. Launch a browser and navigate to the CAM web console.

    Note

    If you try to access the CAM web console immediately after installing the Cluster Application Migration Operator, the console may not load because the Operator is still configuring the cluster. Wait a few minutes and retry.

  4. If you are using self-signed CA certificates, you will be prompted to accept the CA certificate of the source cluster’s API server. The web page guides you through the process of accepting the remaining certificates.
  5. Log in with your OpenShift Container Platform username and password.

2.3. Configuring a replication repository

You must configure an object storage to use as a replication repository. The Cluster Application Migration tool copies data from the source cluster to the replication repository, and then from the replication repository to the target cluster, using either the file system or the snapshot data copy method.

The following storage providers are supported:

2.3.1. Understanding the data copy methods for migration

The CAM tool supports the file system and snapshot data copy methods for migrating data from the source cluster to the target cluster. You can select a method that is suited for your environment and is supported by your storage provider.

2.3.1.1. File system copy method

The CAM tool copies data files from the source cluster to the replication repository, and from there to the target cluster.

Table 2.1. File system copy method summary

BenefitsLimitations
  • Clusters can have different storage classes
  • Supported for all S3 storage providers
  • Optional data verification with checksum
  • Slower than the snapshot copy method
  • Optional data verification significantly reduces performance

2.3.1.2. Snapshot copy method

The CAM tool copies a snapshot of the source cluster’s data to a cloud provider’s object storage, configured as a replication repository. The data is restored on the target cluster.

AWS, Google Cloud Provider, and Microsoft Azure support the snapshot copy method.

Table 2.2. Snapshot copy method summary

BenefitsLimitations
  • Faster than the file system copy method
  • Cloud provider must support snapshots.
  • Clusters must be on the same cloud provider.
  • Clusters must be in the same location or region.
  • Clusters must have the same storage class.
  • Storage class must be compatible with snapshots.

2.3.2. Configuring a Multi-Cloud Object Gateway storage bucket as a replication repository

You can install the OpenShift Container Storage Operator and configure a Multi-Cloud Object Gateway (MCG) storage bucket as a replication repository.

2.3.2.1. Installing the OpenShift Container Storage Operator

You can install the OpenShift Container Storage Operator from OperatorHub.

Procedure

  1. In the OpenShift Container Platform web console, click OperatorsOperatorHub.
  2. Use Filter by keyword (in this case, OCS) to find the OpenShift Container Storage Operator.
  3. Select the OpenShift Container Storage Operator and click Install.
  4. Select an Update Channel, Installation Mode, and Approval Strategy.
  5. Click Subscribe.

    On the Installed Operators page, the OpenShift Container Storage Operator appears in the openshift-storage project with the status Succeeded.

2.3.2.2. Creating the Multi-Cloud Object Gateway storage bucket

You can create the Multi-Cloud Object Gateway (MCG) storage bucket’s Custom Resources (CRs).

Procedure

  1. Log in to the OpenShift Container Platform cluster:

    $ oc login
  2. Create the NooBaa CR configuration file, noobaa.yml, with the following content:

    apiVersion: noobaa.io/v1alpha1
    kind: NooBaa
    metadata:
      name: noobaa
      namespace: openshift-storage
    spec:
     dbResources:
       requests:
         cpu: 0.5 1
         memory: 1Gi
     coreResources:
       requests:
         cpu: 0.5 2
         memory: 1Gi
    1 2
    For a very small cluster, you can change the cpu value to 0.1.
  3. Create the NooBaa object:

    $ oc create -f noobaa.yml
  4. Create the BackingStore CR configuration file, bs.yml, with the following content:

    apiVersion: noobaa.io/v1alpha1
    kind: BackingStore
    metadata:
      finalizers:
      - noobaa.io/finalizer
      labels:
        app: noobaa
      name: mcg-pv-pool-bs
      namespace: openshift-storage
    spec:
      pvPool:
        numVolumes: 3 1
        resources:
          requests:
            storage: 50Gi 2
        storageClass: gp2 3
      type: pv-pool
    1
    Specify the number of volumes in the PV pool.
    2
    Specify the size of the volumes.
    3
    Specify the storage class.
  5. Create the BackingStore object:

    $ oc create -f bs.yml
  6. Create the BucketClass CR configuration file, bc.yml, with the following content:

    apiVersion: noobaa.io/v1alpha1
    kind: BucketClass
    metadata:
      labels:
        app: noobaa
      name: mcg-pv-pool-bc
      namespace: openshift-storage
    spec:
      placementPolicy:
        tiers:
        - backingStores:
          - mcg-pv-pool-bs
          placement: Spread
  7. Create the BucketClass object:

    $ oc create -f bc.yml
  8. Create the ObjectBucketClaim CR configuration file, obc.yml, with the following content:

    apiVersion: objectbucket.io/v1alpha1
    kind: ObjectBucketClaim
    metadata:
      name: migstorage
      namespace: openshift-storage
    spec:
      bucketName: migstorage 1
      storageClassName: openshift-storage.noobaa.io
      additionalConfig:
        bucketclass: mcg-pv-pool-bc
    1
    Record the bucket name for adding the replication repository to the CAM web console.
  9. Create the ObjectBucketClaim object:

    $ oc create -f obc.yml
  10. Watch the resource creation process to verify that the ObjectBucketClaim status is Bound:

    $ watch -n 30 'oc get -n openshift-storage objectbucketclaim migstorage -o yaml'

    This process can take five to ten minutes.

  11. Obtain and record the following values, which are required when you add the replication repository to the CAM web console:

    • S3 endpoint:

      $ oc get route -n openshift-storage s3
    • S3 provider access key:

      $ oc get secret -n openshift-storage migstorage -o go-template='{{ .data.AWS_ACCESS_KEY_ID }}' | base64 -d
    • S3 provider secret access key:

      $ oc get secret -n openshift-storage migstorage -o go-template='{{ .data.AWS_SECRET_ACCESS_KEY }}' | base64 -d

2.3.3. Configuring an AWS S3 storage bucket as a replication repository

You can configure an AWS S3 storage bucket as a replication repository.

Prerequisites

  • The AWS S3 storage bucket must be accessible to the source and target clusters.
  • You must have the AWS CLI installed.
  • If you are using the snapshot copy method:

    • You must have access to EC2 Elastic Block Storage (EBS).
    • The source and target clusters must be in the same region.
    • The source and target clusters must have the same storage class.
    • The storage class must be compatible with snapshots.

Procedure

  1. Create an AWS S3 bucket:

    $ aws s3api create-bucket \
        --bucket <bucket_name> \ 1
        --region <bucket_region> 2
    1
    Specify your S3 bucket name.
    2
    Specify your S3 bucket region, for example, us-east-1.
  2. Create the IAM user velero:

    $ aws iam create-user --user-name velero
  3. Create an EC2 EBS snapshot policy:

    $ cat > velero-ec2-snapshot-policy.json <<EOF
    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Effect": "Allow",
                "Action": [
                    "ec2:DescribeVolumes",
                    "ec2:DescribeSnapshots",
                    "ec2:CreateTags",
                    "ec2:CreateVolume",
                    "ec2:CreateSnapshot",
                    "ec2:DeleteSnapshot"
                ],
                "Resource": "*"
            }
        ]
    }
    EOF
  4. Create an AWS S3 access policy for one or for all S3 buckets:

    $ cat > velero-s3-policy.json <<EOF
    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Effect": "Allow",
                "Action": [
                    "s3:GetObject",
                    "s3:DeleteObject",
                    "s3:PutObject",
                    "s3:AbortMultipartUpload",
                    "s3:ListMultipartUploadParts"
                ],
                "Resource": [
                    "arn:aws:s3:::<bucket_name>/*" 1
                ]
            },
            {
                "Effect": "Allow",
                "Action": [
                    "s3:ListBucket",
                    "s3:GetBucketLocation",
                    "s3:ListBucketMultipartUploads"
                ],
                "Resource": [
                    "arn:aws:s3:::<bucket_name>" 2
                ]
            }
        ]
    }
    EOF
    1 2
    To grant access to a single S3 bucket, specify the bucket name. To grant access to all AWS S3 buckets, specify * instead of a bucket name:
    "Resource": [
        "arn:aws:s3:::*"
  5. Attach the EC2 EBS policy to velero:

    $ aws iam put-user-policy \
      --user-name velero \
      --policy-name velero-ebs \
      --policy-document file://velero-ec2-snapshot-policy.json
  6. Attach the AWS S3 policy to velero:

    $ aws iam put-user-policy \
      --user-name velero \
      --policy-name velero-s3 \
      --policy-document file://velero-s3-policy.json
  7. Create an access key for velero:

    $ aws iam create-access-key --user-name velero
    {
      "AccessKey": {
            "UserName": "velero",
            "Status": "Active",
            "CreateDate": "2017-07-31T22:24:41.576Z",
            "SecretAccessKey": <AWS_SECRET_ACCESS_KEY>, 1
            "AccessKeyId": <AWS_ACCESS_KEY_ID> 2
        }
    }
    1 2
    Record the AWS_SECRET_ACCESS_KEY and the AWS_ACCESS_KEY_ID for adding the AWS repository to the CAM web console.

2.3.4. Configuring a Google Cloud Provider storage bucket as a replication repository

You can configure a Google Cloud Provider (GCP) storage bucket as a replication repository.

Prerequisites

  • The GCP storage bucket must be accessible to the source and target clusters.
  • You must have gsutil installed.
  • If you are using the snapshot copy method:

    • The source and target clusters must be in the same region.
    • The source and target clusters must have the same storage class.
    • The storage class must be compatible with snapshots.

Procedure

  1. Run gsutil init to log in:

    $ gsutil init
    Welcome! This command will take you through the configuration of gcloud.
    
    Your current configuration has been set to: [default]
    
    To continue, you must login. Would you like to login (Y/n)?
  2. Set the BUCKET variable:

    $ BUCKET=<bucket_name> 1
    1
    Specify your bucket name.
  3. Create a storage bucket:

    $ gsutil mb gs://$BUCKET/
  4. Set the PROJECT_ID variable to your active project:

    $ PROJECT_ID=$(gcloud config get-value project)
  5. Create a velero service account:

    $ gcloud iam service-accounts create velero \
        --display-name "Velero Storage"
  6. Set the SERVICE_ACCOUNT_EMAIL variable to the service account’s email address:

    $ SERVICE_ACCOUNT_EMAIL=$(gcloud iam service-accounts list \
      --filter="displayName:Velero Storage" \
      --format 'value(email)')
  7. Grant permissions to the service account:

    $ ROLE_PERMISSIONS=(
        compute.disks.get
        compute.disks.create
        compute.disks.createSnapshot
        compute.snapshots.get
        compute.snapshots.create
        compute.snapshots.useReadOnly
        compute.snapshots.delete
        compute.zones.get
    )
    
    gcloud iam roles create velero.server \
        --project $PROJECT_ID \
        --title "Velero Server" \
        --permissions "$(IFS=","; echo "${ROLE_PERMISSIONS[*]}")"
    
    gcloud projects add-iam-policy-binding $PROJECT_ID \
        --member serviceAccount:$SERVICE_ACCOUNT_EMAIL \
        --role projects/$PROJECT_ID/roles/velero.server
    
    gsutil iam ch serviceAccount:$SERVICE_ACCOUNT_EMAIL:objectAdmin gs://${BUCKET}
  8. Save the service account’s keys to the credentials-velero file in the current directory:

    $ gcloud iam service-accounts keys create credentials-velero \
      --iam-account $SERVICE_ACCOUNT_EMAIL

2.3.5. Configuring a Microsoft Azure Blob storage container as a replication repository

You can configure a Microsoft Azure Blob storage container as a replication repository.

Prerequisites

  • You must have an Azure storage account.
  • You must have the Azure CLI installed.
  • The Azure Blob storage container must be accessible to the source and target clusters.
  • If you are using the snapshot copy method:

    • The source and target clusters must be in the same region.
    • The source and target clusters must have the same storage class.
    • The storage class must be compatible with snapshots.

Procedure

  1. Set the AZURE_RESOURCE_GROUP variable:

    $ AZURE_RESOURCE_GROUP=Velero_Backups
  2. Create an Azure resource group:

    $ az group create -n $AZURE_RESOURCE_GROUP --location <CentralUS> 1
    1
    Specify your location.
  3. Set the AZURE_STORAGE_ACCOUNT_ID variable:

    $ AZURE_STORAGE_ACCOUNT_ID=velerobackups
  4. Create an Azure storage account:

    $ az storage account create \
      --name $AZURE_STORAGE_ACCOUNT_ID \
      --resource-group $AZURE_RESOURCE_GROUP \
      --sku Standard_GRS \
      --encryption-services blob \
      --https-only true \
      --kind BlobStorage \
      --access-tier Hot
  5. Set the BLOB_CONTAINER variable:

    $ BLOB_CONTAINER=velero
  6. Create an Azure Blob storage container:

    $ az storage container create \
      -n $BLOB_CONTAINER \
      --public-access off \
      --account-name $AZURE_STORAGE_ACCOUNT_ID
  7. Create a service principal and credentials for velero:

    $ AZURE_SUBSCRIPTION_ID=`az account list --query '[?isDefault].id' -o tsv`
    $ AZURE_TENANT_ID=`az account list --query '[?isDefault].tenantId' -o tsv`
    $ AZURE_CLIENT_SECRET=`az ad sp create-for-rbac --name "velero" --role "Contributor" --query 'password' -o tsv`
    $ AZURE_CLIENT_ID=`az ad sp list --display-name "velero" --query '[0].appId' -o tsv`
  8. Save the service principal’s credentials in the credentials-velero file:

    $ cat << EOF  > ./credentials-velero
    AZURE_SUBSCRIPTION_ID=${AZURE_SUBSCRIPTION_ID}
    AZURE_TENANT_ID=${AZURE_TENANT_ID}
    AZURE_CLIENT_ID=${AZURE_CLIENT_ID}
    AZURE_CLIENT_SECRET=${AZURE_CLIENT_SECRET}
    AZURE_RESOURCE_GROUP=${AZURE_RESOURCE_GROUP}
    AZURE_CLOUD_NAME=AzurePublicCloud
    EOF

2.4. Migrating applications with the CAM web console

You can migrate application workloads by adding your clusters and replication repository to the CAM web console. Then, you can create and run a migration plan.

If your cluster or replication repository are secured with self-signed certificates, you can create a CA certificate bundle file or disable SSL verification.

2.4.1. Creating a CA certificate bundle file

If you use a self-signed certificate to secure a cluster or a replication repository, certificate verification might fail with the following error message: Certificate signed by unknown authority.

You can create a custom CA certificate bundle file and upload it in the CAM web console when you add a cluster or a replication repository.

Procedure

Download a CA certificate from a remote endpoint and save it as a CA bundle file:

$ echo -n | openssl s_client -connect <host_FQDN>:<port> \ 1
  | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > <ca_bundle.cert> 2
1
Specify the host FQDN and port of the endpoint, for example, api.my-cluster.example.com:6443.
2
Specify the name of the CA bundle file.

2.4.2. Adding a cluster to the CAM web console

You can add a cluster to the CAM web console.

Prerequisites

If you are using Azure snapshots to copy data:

  • You must provide the Azure resource group name when you add the source cluster.
  • The source and target clusters must be in the same Azure resource group and in the same location.

Procedure

  1. Log in to the cluster.
  2. Obtain the service account token:

    $ oc sa get-token mig -n openshift-migration
    eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJtaWciLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlY3JldC5uYW1lIjoibWlnLXRva2VuLWs4dDJyIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6Im1pZyIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50LnVpZCI6ImE1YjFiYWMwLWMxYmYtMTFlOS05Y2NiLTAyOWRmODYwYjMwOCIsInN1YiI6InN5c3RlbTpzZXJ2aWNlYWNjb3VudDptaWc6bWlnIn0.xqeeAINK7UXpdRqAtOj70qhBJPeMwmgLomV9iFxr5RoqUgKchZRG2J2rkqmPm6vr7K-cm7ibD1IBpdQJCcVDuoHYsFgV4mp9vgOfn9osSDp2TGikwNz4Az95e81xnjVUmzh-NjDsEpw71DH92iHV_xt2sTwtzftS49LpPW2LjrV0evtNBP_t_RfskdArt5VSv25eORl7zScqfe1CiMkcVbf2UqACQjo3LbkpfN26HAioO2oH0ECPiRzT0Xyh-KwFutJLS9Xgghyw-LD9kPKcE_xbbJ9Y4Rqajh7WdPYuB0Jd9DPVrslmzK-F6cgHHYoZEv0SvLQi-PO0rpDrcjOEQQ
  3. Log in to the CAM web console.
  4. In the Clusters section, click Add cluster.
  5. Fill in the following fields:

    • Cluster name: May contain lower-case letters (a-z) and numbers (0-9). Must not contain spaces or international characters.
    • Url: URL of the cluster’s API server, for example, https://<master1.example.com>:8443.
    • Service account token: String that you obtained from the source cluster.
    • Azure cluster: Optional. Select it if you are using Azure snapshots to copy your data.
    • Azure resource group: This field appears if Azure cluster is checked.
    • If you use a custom CA bundle, click Browse and browse to the CA bundle file.
  6. Click Add cluster.

    The cluster appears in the Clusters section.

2.4.3. Adding a replication repository to the CAM web console

You can add an object storage bucket as a replication repository to the CAM web console.

Prerequisites

  • You must configure an object storage bucket for migrating the data.

Procedure

  1. Log in to the CAM web console.
  2. In the Replication repositories section, click Add repository.
  3. Select a Storage provider type and fill in the following fields:

    • AWS for AWS S3, MCG, and generic S3 providers:

      • Replication repository name: Specify the replication repository name in the CAM web console.
      • S3 bucket name: Specify the name of the S3 bucket you created.
      • S3 bucket region: Specify the S3 bucket region. Required for AWS S3. Optional for other S3 providers.
      • S3 endpoint: Specify the URL of the S3 service, not the bucket, for example, https://<s3-storage.apps.cluster.com>. Required for a generic S3 provider. You must use the https:// prefix.
      • S3 provider access key: Specify the <AWS_SECRET_ACCESS_KEY> for AWS or the S3 provider access key for MCG.
      • S3 provider secret access key: Specify the <AWS_ACCESS_KEY_ID> for AWS or the S3 provider secret access key for MCG.
      • Require SSL verification: Clear this check box if you are using a generic S3 provider.
      • If you use a custom CA bundle, click Browse and browse to the Base64-encoded CA bundle file.
    • GCP:

      • Replication repository name: Specify the replication repository name in the CAM web console.
      • GCP bucket name: Specify the name of the GCP bucket.
      • GCP credential JSON blob: Specify the string in the credentials-velero file.
    • Azure:

      • Replication repository name: Specify the replication repository name in the CAM web console.
      • Azure resource group: Specify the resource group of the Azure Blob storage.
      • Azure storage account name: Specify the Azure Blob storage account name.
      • Azure credentials - INI file contents: Specify the string in the credentials-velero file.
  4. Click Add repository and wait for connection validation.
  5. Click Close.

    The new repository appears in the Replication repositories section.

2.4.4. Changing migration plan limits for large migrations

You can change the migration plan limits for large migrations.

Important

Changes should first be tested in your environment to avoid a failed migration.

A single migration plan has the following default limits:

  • 10 namespaces

    If this limit is exceeded, the CAM web console displays a Namespace limit exceeded error and you cannot create a migration plan.

  • 100 Pods

    If the Pod limit is exceeded, the CAM web console displays a warning message similar to the following example: Plan has been validated with warning condition(s). See warning message. Pod limit: 100 exceeded, found: 104.

  • 100 persistent volumes

    If the persistent volume limit is exceeded, the CAM web console displays a similar warning message.

Procedure

  1. Edit the Migration controller CR:

    $ oc get migrationcontroller -n openshift-migration
    NAME AGE
    migration-controller 5d19h
    
    $ oc edit migrationcontroller -n openshift-migration
  2. Update the following parameters:

    [...]
    migration_controller: true
    
    # This configuration is loaded into mig-controller, and should be set on the
    # cluster where `migration_controller: true`
    mig_pv_limit: 100
    mig_pod_limit: 100
    mig_namespace_limit: 10
    [...]

2.4.5. Creating a migration plan in the CAM web console

You can create a migration plan in the CAM web console.

Prerequisites

  • The CAM web console must contain the following:

    • Source cluster
    • Target cluster, which is added automatically during the CAM tool installation
    • Replication repository
  • If you use snapshots to copy data, the source and target clusters must be running on the same cloud provider (AWS, GCP, or Azure) and in the same region.

Procedure

  1. Log in to the CAM web console.
  2. In the Plans section, click Add plan.
  3. Enter the Plan name and click Next.

    The Plan name can contain up to 253 lower-case alphanumeric characters (a-z, 0-9). It must not contain spaces or underscores (_).

  4. Select a Source cluster.
  5. Select a Target cluster.
  6. Select a Replication repository.
  7. Select the projects to be migrated and click Next.
  8. Select Copy or Move for the PVs:

    • Copy copies the data in a source cluster’s PV to the replication repository and then restores it on a newly created PV, with similar characteristics, in the target cluster.

      Optional: You can verify data copied with the filesystem method by selecting Verify copy. This option, which generates a checksum for each source file and checks it after restoration, significantly reduces performance.

    • Move unmounts a remote volume (for example, NFS) from the source cluster, creates a PV resource on the target cluster pointing to the remote volume, and then mounts the remote volume on the target cluster. Applications running on the target cluster use the same remote volume that the source cluster was using. The remote volume must be accessible to the source and target clusters.
  9. Click Next.
  10. Select a Copy method for the PVs:

    • Snapshot backs up and restores the disk using the cloud provider’s snapshot functionality. It is significantly faster than Filesystem.

      Note

      The storage and clusters must be in the same region and the storage class must be compatible.

    • Filesystem copies the data files from the source disk to a newly created target disk.
  11. Select a Storage class for the PVs.

    If you selected the Filesystem copy method, you can change the storage class during migration, for example, from Red Hat Gluster Storage or NFS storage to Red Hat Ceph Storage.

  12. Click Next.
  13. If you want to add a migration hook, click Add Hook and perform the following steps:

    1. Specify the name of the hook.
    2. Select Ansible playbook to use your own playbook or Custom container image for a hook written in another language.
    3. Click Browse to upload the playbook.
    4. Optional: If you are not using the default Ansible runtime image, specify your custom Ansible image.
    5. Specify the cluster on which you want the hook to run.
    6. Specify the service account name.
    7. Specify the namespace.
    8. Select the migration step at which you want the hook to run:

      • PreBackup: Before backup tasks are started on the source cluster
      • PostBackup: After backup tasks are complete on the source cluster
      • PreRestore: Before restore tasks are started on the target cluster
      • PostRestore: After restore tasks are complete on the target cluster
  14. Click Add.

    You can add up to four hooks to a migration plan, assigning each hook to a different migration step.

  15. Click Finish.
  16. Click Close.

    The migration plan appears in the Plans section.

2.4.6. Running a migration plan in the CAM web console

You can stage or migrate applications and data with the migration plan you created in the CAM web console.

Prerequisites

The CAM web console must contain the following:

  • Source cluster
  • Target cluster, which is added automatically during the CAM tool installation
  • Replication repository
  • Valid migration plan

Procedure

  1. Log in to the CAM web console on the target cluster.
  2. Select a migration plan.
  3. Click Stage to copy data from the source cluster to the target cluster without stopping the application.

    You can run Stage multiple times to reduce the actual migration time.

  4. When you are ready to migrate the application workload, click Migrate.

    Migrate stops the application workload on the source cluster and recreates its resources on the target cluster.

  5. Optional: In the Migrate window, you can select Do not stop applications on the source cluster during migration.
  6. Click Migrate.
  7. When the migration is complete, verify that the application migrated successfully in the OpenShift Container Platform web console:

    1. Click HomeProjects.
    2. Click the migrated project to view its status.
    3. In the Routes section, click Location to verify that the application is functioning, if applicable.
    4. Click WorkloadsPods to verify that the Pods are running in the migrated namespace.
    5. Click StoragePersistent volumes to verify that the migrated persistent volume is correctly provisioned.

2.5. Troubleshooting

You can view the migration Custom Resources (CRs) and download logs to troubleshoot a failed migration.

If the application was stopped during the failed migration, you must roll it back manually in order to prevent data corruption.

Note

Manual rollback is not required if the application was not stopped during migration, because the original application is still running on the source cluster.

2.5.1. Viewing migration Custom Resources

The Cluster Application Migration (CAM) tool creates the following Custom Resources (CRs):

migration architecture diagram

20 MigCluster (configuration, CAM cluster): Cluster definition

20 MigStorage (configuration, CAM cluster): Storage definition

20 MigPlan (configuration, CAM cluster): Migration plan

The MigPlan CR describes the source and target clusters, repository, and namespace(s) being migrated. It is associated with 0, 1, or many MigMigration CRs.

Note

Deleting a MigPlan CR deletes the associated MigMigration CRs.

20 BackupStorageLocation (configuration, CAM cluster): Location of Velero backup objects

20 VolumeSnapshotLocation (configuration, CAM cluster): Location of Velero volume snapshots

20 MigMigration (action, CAM cluster): Migration, created during migration

A MigMigration CR is created every time you stage or migrate data. Each MigMigration CR is associated with a MigPlan CR.

20 Backup (action, source cluster): When you run a migration plan, the MigMigration CR creates two Velero backup CRs on each source cluster:

  • Backup CR #1 for Kubernetes objects
  • Backup CR #2 for PV data

20 Restore (action, target cluster): When you run a migration plan, the MigMigration CR creates two Velero restore CRs on the target cluster:

  • Restore CR #1 (using Backup CR #2) for PV data
  • Restore CR #2 (using Backup CR #1) for Kubernetes objects

Procedure

  1. Get the CR name:

    $ oc get <migration_cr> -n openshift-migration 1
    1
    Specify the migration CR, for example, migmigration.

    The output is similar to the following:

    NAME                                   AGE
    88435fe0-c9f8-11e9-85e6-5d593ce65e10   6m42s
  2. View the CR:

    $ oc describe <migration_cr> <88435fe0-c9f8-11e9-85e6-5d593ce65e10> -n openshift-migration

    The output is similar to the following examples.

MigMigration example

name:         88435fe0-c9f8-11e9-85e6-5d593ce65e10
namespace:    openshift-migration
labels:       <none>
annotations:  touch: 3b48b543-b53e-4e44-9d34-33563f0f8147
apiVersion:  migration.openshift.io/v1alpha1
kind:         MigMigration
metadata:
  creationTimestamp:  2019-08-29T01:01:29Z
  generation:          20
  resourceVersion:    88179
  selfLink:           /apis/migration.openshift.io/v1alpha1/namespaces/openshift-migration/migmigrations/88435fe0-c9f8-11e9-85e6-5d593ce65e10
  uid:                 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
spec:
  migPlanRef:
    name:        socks-shop-mig-plan
    namespace:   openshift-migration
  quiescePods:  true
  stage:         false
status:
  conditions:
    category:              Advisory
    durable:               True
    lastTransitionTime:  2019-08-29T01:03:40Z
    message:               The migration has completed successfully.
    reason:                Completed
    status:                True
    type:                  Succeeded
  phase:                   Completed
  startTimestamp:         2019-08-29T01:01:29Z
events:                    <none>

Velero backup CR #2 example (PV data)

apiVersion: velero.io/v1
kind: Backup
metadata:
  annotations:
    openshift.io/migrate-copy-phase: final
    openshift.io/migrate-quiesce-pods: "true"
    openshift.io/migration-registry: 172.30.105.179:5000
    openshift.io/migration-registry-dir: /socks-shop-mig-plan-registry-44dd3bd5-c9f8-11e9-95ad-0205fe66cbb6
  creationTimestamp: "2019-08-29T01:03:15Z"
  generateName: 88435fe0-c9f8-11e9-85e6-5d593ce65e10-
  generation: 1
  labels:
    app.kubernetes.io/part-of: migration
    migmigration: 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
    migration-stage-backup: 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
    velero.io/storage-location: myrepo-vpzq9
  name: 88435fe0-c9f8-11e9-85e6-5d593ce65e10-59gb7
  namespace: openshift-migration
  resourceVersion: "87313"
  selfLink: /apis/velero.io/v1/namespaces/openshift-migration/backups/88435fe0-c9f8-11e9-85e6-5d593ce65e10-59gb7
  uid: c80dbbc0-c9f8-11e9-95ad-0205fe66cbb6
spec:
  excludedNamespaces: []
  excludedResources: []
  hooks:
    resources: []
  includeClusterResources: null
  includedNamespaces:
  - sock-shop
  includedResources:
  - persistentvolumes
  - persistentvolumeclaims
  - namespaces
  - imagestreams
  - imagestreamtags
  - secrets
  - configmaps
  - pods
  labelSelector:
    matchLabels:
      migration-included-stage-backup: 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
  storageLocation: myrepo-vpzq9
  ttl: 720h0m0s
  volumeSnapshotLocations:
  - myrepo-wv6fx
status:
  completionTimestamp: "2019-08-29T01:02:36Z"
  errors: 0
  expiration: "2019-09-28T01:02:35Z"
  phase: Completed
  startTimestamp: "2019-08-29T01:02:35Z"
  validationErrors: null
  version: 1
  volumeSnapshotsAttempted: 0
  volumeSnapshotsCompleted: 0
  warnings: 0

Velero restore CR #2 example (Kubernetes resources)

apiVersion: velero.io/v1
kind: Restore
metadata:
  annotations:
    openshift.io/migrate-copy-phase: final
    openshift.io/migrate-quiesce-pods: "true"
    openshift.io/migration-registry: 172.30.90.187:5000
    openshift.io/migration-registry-dir: /socks-shop-mig-plan-registry-36f54ca7-c925-11e9-825a-06fa9fb68c88
  creationTimestamp: "2019-08-28T00:09:49Z"
  generateName: e13a1b60-c927-11e9-9555-d129df7f3b96-
  generation: 3
  labels:
    app.kubernetes.io/part-of: migration
    migmigration: e18252c9-c927-11e9-825a-06fa9fb68c88
    migration-final-restore: e18252c9-c927-11e9-825a-06fa9fb68c88
  name: e13a1b60-c927-11e9-9555-d129df7f3b96-gb8nx
  namespace: openshift-migration
  resourceVersion: "82329"
  selfLink: /apis/velero.io/v1/namespaces/openshift-migration/restores/e13a1b60-c927-11e9-9555-d129df7f3b96-gb8nx
  uid: 26983ec0-c928-11e9-825a-06fa9fb68c88
spec:
  backupName: e13a1b60-c927-11e9-9555-d129df7f3b96-sz24f
  excludedNamespaces: null
  excludedResources:
  - nodes
  - events
  - events.events.k8s.io
  - backups.velero.io
  - restores.velero.io
  - resticrepositories.velero.io
  includedNamespaces: null
  includedResources: null
  namespaceMapping: null
  restorePVs: true
status:
  errors: 0
  failureReason: ""
  phase: Completed
  validationErrors: null
  warnings: 15

2.5.2. Downloading migration logs

You can download the Velero, Restic, and Migration controller logs in the CAM web console to troubleshoot a failed migration.

Procedure

  1. Log in to the CAM console.
  2. Click Plans to view the list of migration plans.
  3. Click the Options menu kebab of a specific migration plan and select Logs.
  4. Click Download Logs to download the logs of the Migration controller, Velero, and Restic for all clusters.
  5. To download a specific log:

    1. Specify the log options:

      • Cluster: Select the source, target, or CAM host cluster.
      • Log source: Select Velero, Restic, or Controller.
      • Pod source: Select the Pod name, for example, controller-manager-78c469849c-v6wcf

        The selected log is displayed.

        You can clear the log selection settings by changing your selection.

    2. Click Download Selected to download the selected log.

Optionally, you can access the logs by using the CLI, as in the following example:

$ oc get pods -n openshift-migration | grep controller
controller-manager-78c469849c-v6wcf           1/1     Running     0          4h49m

$ oc logs controller-manager-78c469849c-v6wcf -f -n openshift-migration

2.5.3. Error messages

2.5.3.1. Restic timeout error message in the Velero Pod log

If a migration fails because Restic times out, the following error appears in the Velero Pod log:

level=error msg="Error backing up item" backup=velero/monitoring error="timed out waiting for all PodVolumeBackups to complete" error.file="/go/src/github.com/heptio/velero/pkg/restic/backupper.go:165" error.function="github.com/heptio/velero/pkg/restic.(*backupper).BackupPodVolumes" group=v1

The default value of restic_timeout is one hour. You can increase this parameter for large migrations, keeping in mind that a higher value may delay the return of error messages.

Procedure

  1. In the OpenShift Container Platform web console, navigate to OperatorsInstalled Operators.
  2. Click Cluster Application Migration Operator.
  3. In the MigrationController tab, click migration-controller.
  4. In the YAML tab, update the following parameter value:

    spec:
      restic_timeout: 1h 1
    1
    Valid units are h (hours), m (minutes), and s (seconds), for example, 3h30m15s.
  5. Click Save.

2.5.3.2. ResticVerifyErrors in the MigMigration Custom Resource

If data verification fails when migrating a PV with the filesystem data copy method, the following error appears in the MigMigration Custom Resource (CR):

status:
  conditions:
  - category: Warn
    durable: true
    lastTransitionTime: 2020-04-16T20:35:16Z
    message: There were verify errors found in 1 Restic volume restores. See restore `<registry-example-migration-rvwcm>`
      for details 1
    status: "True"
    type: ResticVerifyErrors 2
1
The error message identifies the Restore CR name.
2
ResticErrors also appears. ResticErrors is a general error warning that includes verification errors.
Note

A data verification error does not cause the migration process to fail.

You can check the target cluster’s Restore CR to identify the source of the data verification error.

Procedure

  1. Log in to the target cluster.
  2. View the Restore CR:

    $ oc describe <registry-example-migration-rvwcm> -n openshift-migration

    The output identifies the PV with PodVolumeRestore errors:

    status:
      phase: Completed
      podVolumeRestoreErrors:
      - kind: PodVolumeRestore
        name: <registry-example-migration-rvwcm-98t49>
        namespace: openshift-migration
      podVolumeRestoreResticErrors:
      - kind: PodVolumeRestore
        name: <registry-example-migration-rvwcm-98t49>
        namespace: openshift-migration
  3. View the PodVolumeRestore CR:

    $ oc describe <migration-example-rvwcm-98t49>

    The output identifies the Restic Pod that logged the errors:

      completionTimestamp: 2020-05-01T20:49:12Z
      errors: 1
      resticErrors: 1
    ...
      resticPod: <restic-nr2v5>
  4. View the Restic Pod log:

    $ oc logs -f restic-nr2v5

2.5.4. Manually rolling back a migration

If your application was stopped during a failed migration, you must roll it back manually in order to prevent data corruption in the PV.

This procedure is not required if the application was not stopped during migration, because the original application is still running on the source cluster.

Procedure

  1. On the target cluster, switch to the migrated project:

    $ oc project <project>
  2. Get the deployed resources:

    $ oc get all
  3. Delete the deployed resources to ensure that the application is not running on the target cluster and accessing data on the PVC:

    $ oc delete <resource_type>
  4. To stop a DaemonSet without deleting it, update the nodeSelector in the YAML file:

    apiVersion: apps/v1
    kind: DaemonSet
    metadata:
      name: hello-daemonset
    spec:
      selector:
          matchLabels:
            name: hello-daemonset
      template:
        metadata:
          labels:
            name: hello-daemonset
        spec:
          nodeSelector:
            role: worker 1
    1
    Specify a nodeSelector value that does not exist on any node.
  5. Update each PV’s reclaim policy so that unnecessary data is removed. During migration, the reclaim policy for bound PVs is Retain, to ensure that data is not lost when an application is removed from the source cluster. You can remove these PVs during rollback.

    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv0001
    spec:
      capacity:
        storage: 5Gi
      accessModes:
        - ReadWriteOnce
      persistentVolumeReclaimPolicy: Retain 1
      ...
    status:
      ...
    1
    Specify Recycle or Delete.
  6. On the source cluster, switch to the migrated project and get its deployed resources:

    $ oc project <project>
    $ oc get all
  7. Start one or more replicas of each deployed resource:

    $ oc scale --replicas=1 <resource_type>/<resource_name>
  8. Update the nodeSelector of a DaemonSet to its original value, if you changed it during the procedure.

2.5.5. Gathering data for a customer support case

If you open a customer support case, you can run the must-gather tool with the openshift-migration-must-gather-rhel8 image to collect information about your cluster and upload it to the Red Hat Customer Portal.

The openshift-migration-must-gather-rhel8 image collects logs and Custom Resource data that are not collected by the default must-gather image.

Procedure

  1. Navigate to the directory where you want to store the must-gather data.
  2. Run the oc adm must-gather command:

    $ oc adm must-gather --image=registry.redhat.io/rhcam-1-2/openshift-migration-must-gather-rhel8

    The must-gather tool collects the cluster information and stores it in a must-gather.local.<uid> directory.

  3. Remove authentication keys and other sensitive information from the must-gather data.
  4. Create an archive file containing the contents of the must-gather.local.<uid> directory:

    $ tar cvaf must-gather.tar.gz must-gather.local.<uid>/

    You can attach the compressed file to your customer support case on the Red Hat Customer Portal.

2.5.6. Known issues

This release has the following known issues:

  • During migration, the Cluster Application Migration (CAM) tool preserves the following namespace annotations:

    • openshift.io/sa.scc.mcs
    • openshift.io/sa.scc.supplemental-groups
    • openshift.io/sa.scc.uid-range

      These annotations preserve the UID range, ensuring that the containers retain their file system permissions on the target cluster. There is a risk that the migrated UIDs could duplicate UIDs within an existing or future namespace on the target cluster. (BZ#1748440)

  • If an AWS bucket is added to the CAM web console and then deleted, its status remains True because the MigStorage CR is not updated. (BZ#1738564)
  • Most cluster-scoped resources are not yet handled by the CAM tool. If your applications require cluster-scoped resources, you may have to create them manually on the target cluster.
  • If a migration fails, the migration plan does not retain custom PV settings for quiesced pods. You must manually roll back the migration, delete the migration plan, and create a new migration plan with your PV settings. (BZ#1784899)
  • If a large migration fails because Restic times out, you can increase the restic_timeout parameter value (default: 1h) in the Migration controller CR.
  • If you select the data verification option for PVs that are migrated with the filesystem copy method, performance is significantly slower. Velero generates a checksum for each file and checks it when the file is restored.

Chapter 3. Migrating Openshift Container Platform 4.2 to 4.3

3.1. Migrating application workloads from OpenShift Container Platform 4.2 to 4.4

You can migrate application workloads from OpenShift Container Platform 4.2 to 4.4 with the Cluster Application Migration (CAM) tool. The CAM tool enables you to control the migration and to minimize application downtime.

The CAM tool’s web console and API, based on Kubernetes Custom Resources, enable you to migrate stateful and stateless application workloads at the granularity of a namespace.

3.1.1. Migration prerequisites

  • You must have cluster-admin privileges on all clusters.
  • The source and target clusters must have unrestricted network access to the replication repository.
  • The cluster on which the Migration controller is installed must have unrestricted access to the other clusters.
  • If your application uses images from the openshift namespace, the required versions of the images must be present on the target cluster.

    If the required images are not present, you must update the imagestreamtags references to use an available version that is compatible with your application. If the imagestreamtags cannot be updated, you can manually upload equivalent images to the application namespaces and update the applications to reference them.

    The following imagestreamtags have been removed from OpenShift Container Platform 4.4:

    • dotnet: 2.2
    • dotnet-runtime: 2.2
    • nginx: 1.12
    • nodejs: 8, 8-RHOAR, 10-SCL
    • perl:5.24
    • php: 7.0, 7.1
    • redis: 3.2

3.1.2. Understanding the Cluster Application Migration tool

The Cluster Application Migration (CAM) tool enables you to migrate Kubernetes resources, persistent volume data, and internal container images from an OpenShift Container Platform source cluster to an OpenShift Container Platform 4.4 target cluster, using the CAM web console or the Kubernetes API.

Migrating an application with the CAM web console involves the following steps:

  1. Install the Cluster Application Migration Operator on all clusters.

    Note

    The Cluster Application Migration Operator installs the CAM tool (CAM web console and Migration controller) on the target cluster by default. You can configure the Migration controller to install the CAM tool on another cluster. The cluster on which the CAM tool is installed is referred to as the CAM tool cluster.

  2. Configure the replication repository, an intermediate object storage that the CAM tool uses to migrate data.
  3. Add the source cluster to the CAM web console.
  4. Add the replication repository to the CAM web console.
  5. Create a migration plan, with one of the following data migration options:

    • Copy: The CAM tool copies the data from the source cluster to the replication repository, and from the replication repository to the target cluster.

      migration PV copy
    • Move: The CAM tool unmounts a remote volume (for example, NFS) from the source cluster, creates a PV resource on the target cluster pointing to the remote volume, and then mounts the remote volume on the target cluster. Applications running on the target cluster use the same remote volume that the source cluster was using. The remote volume must be accessible to the source and target clusters.

      Note

      Although the replication repository does not appear in this diagram, it is required for the actual migration.

      migration PV move
  6. Run the migration plan, with one of the following options:

    • Stage (optional) copies data to the target cluster without stopping the application.

      Staging can be run multiple times so that most of the data is copied to the target before migration. This minimizes the actual migration time and application downtime.

    • Migrate stops the application on the source cluster and recreates its resources on the target cluster. Optionally, you can migrate the workload without stopping the application.
OCP 3 to 4 App migration

3.1.3. Understanding migration hooks

You can use migration hooks to run Ansible playbooks at certain points during the migration. The hooks are added when you create a migration plan.

Note

If you do not want to use Ansible playbooks, you can create a custom container image and add it to a migration plan.

Migration hooks perform tasks such as customizing application quiescence, manually migrating unsupported data types, and updating applications after migration.

A single migration hook runs on a source or target cluster at one of the following migration steps:

  • PreBackup: Before backup tasks are started on the source cluster
  • PostBackup: After backup tasks are complete on the source cluster
  • PreRestore: Before restore tasks are started on the target cluster
  • PostRestore: After restore tasks are complete on the target cluster

    You can assign one hook to each migration step, up to a maximum of four hooks for a single migration plan.

The default hook-runner image is registry.redhat.io/rhcam-1-2/openshift-migration-hook-runner-rhel7. This image is based on Ansible Runner and includes python-openshift for Ansible Kubernetes resources and an updated oc binary. You can also create your own hook image with additional Ansible modules or tools.

The Ansible playbook is mounted on a hook container as a ConfigMap. The hook container runs as a Job on a cluster with a specified service account and namespace. The Job runs, even if the initial Pod is evicted or killed, until it reaches the default backoffLimit (6) or successful completion.

3.2. Deploying the Cluster Application Migration (CAM) tool

Deploying the Cluster Application Migration (CAM) tool requires installing the Cluster Application Migration Operator on the OpenShift Container Platform 4.2 source and OpenShift Container Platform 4.4 target clusters.

3.2.1. Installing the Cluster Application Migration Operator on an OpenShift Container Platform 4.2 source cluster

You can install the Cluster Application Migration Operator on an OpenShift Container Platform 4.2 source cluster with OLM.

Procedure

  1. In the OpenShift Container Platform web console, click OperatorsOperatorHub.
  2. Use the Filter by keyword field (in this case, Migration) to find the Cluster Application Migration Operator.
  3. Select the Cluster Application Migration Operator and click Install.
  4. On the Create Operator Subscription page, select the openshift-migration namespace, and specify an approval strategy.
  5. Click Subscribe.

    On the Installed Operators page, the Cluster Application Migration Operator appears in the openshift-migration project with the status InstallSucceeded.

  6. Under Provided APIs, click View 12 more…​.
  7. Click Create NewMigrationController.
  8. Update the migration_controller and migration_ui parameters in the spec stanza:

    spec:
      [...]
      migration_controller: false
      migration_ui: false
      [...]
  9. Click Create.
  10. Click WorkloadsPods to verify that the Restic and Velero Pods are running.

3.2.2. Installing the Cluster Application Migration Operator on an OpenShift Container Platform 4.4 target cluster

You can install the Cluster Application Migration Operator on an OpenShift Container Platform 4.4 target cluster with OLM.

The Cluster Application Migration Operator installs the CAM tool on the target cluster by default. If you want to install the CAM tool on a different cluster, you must update the Migration controller configuration so that the Cluster Application Migration Operator does not install the CAM tool on this cluster.

Procedure

  1. In the OpenShift Container Platform web console, click OperatorsOperatorHub.
  2. Use the Filter by keyword field (in this case, Migration) to find the Cluster Application Migration Operator.
  3. Select the Cluster Application Migration Operator and click Install.
  4. On the Create Operator Subscription page, select the openshift-migration namespace, and specify an approval strategy.
  5. Click Subscribe.

    On the Installed Operators page, the Cluster Application Migration Operator appears in the openshift-migration project with the status InstallSucceeded.

  6. Under Provided APIs, click View 12 more…​.
  7. Click Create NewMigrationController.
  8. Click Create.
  9. Click WorkloadsPods to verify that the Controller Manager, Migration UI, Restic, and Velero Pods are running.

3.2.3. Launching the CAM web console

You can launch the CAM web console in a browser.

Procedure

  1. Log in to the OpenShift Container Platform cluster on which you have installed the CAM tool.
  2. Obtain the CAM web console URL by entering the following command:

    $ oc get -n openshift-migration route/migration -o go-template='https://{{ .spec.host }}'
    https://migration-openshift-migration.apps.<cluster>.openshift.com
  3. Launch a browser and navigate to the CAM web console.

    Note

    If you try to access the CAM web console immediately after installing the Cluster Application Migration Operator, the console may not load because the Operator is still configuring the cluster. Wait a few minutes and retry.

  4. If you are using self-signed CA certificates, you will be prompted to accept the CA certificate of the source cluster’s API server. The web page guides you through the process of accepting the remaining certificates.
  5. Log in with your OpenShift Container Platform username and password.

3.3. Configuring a replication repository

You must configure an object storage to use as a replication repository. The Cluster Application Migration tool copies data from the source cluster to the replication repository, and then from the replication repository to the target cluster, using either the file system or the snapshot data copy method.

The following storage providers are supported:

3.3.1. Understanding the data copy methods for migration

The CAM tool supports the file system and snapshot data copy methods for migrating data from the source cluster to the target cluster. You can select a method that is suited for your environment and is supported by your storage provider.

3.3.1.1. File system copy method

The CAM tool copies data files from the source cluster to the replication repository, and from there to the target cluster.

Table 3.1. File system copy method summary

BenefitsLimitations
  • Clusters can have different storage classes
  • Supported for all S3 storage providers
  • Optional data verification with checksum
  • Slower than the snapshot copy method
  • Optional data verification significantly reduces performance

3.3.1.2. Snapshot copy method

The CAM tool copies a snapshot of the source cluster’s data to a cloud provider’s object storage, configured as a replication repository. The data is restored on the target cluster.

AWS, Google Cloud Provider, and Microsoft Azure support the snapshot copy method.

Table 3.2. Snapshot copy method summary

BenefitsLimitations
  • Faster than the file system copy method
  • Cloud provider must support snapshots.
  • Clusters must be on the same cloud provider.
  • Clusters must be in the same location or region.
  • Clusters must have the same storage class.
  • Storage class must be compatible with snapshots.

3.3.2. Configuring a Multi-Cloud Object Gateway storage bucket as a replication repository

You can install the OpenShift Container Storage Operator and configure a Multi-Cloud Object Gateway (MCG) storage bucket as a replication repository.

3.3.2.1. Installing the OpenShift Container Storage Operator

You can install the OpenShift Container Storage Operator from OperatorHub.

Procedure

  1. In the OpenShift Container Platform web console, click OperatorsOperatorHub.
  2. Use Filter by keyword (in this case, OCS) to find the OpenShift Container Storage Operator.
  3. Select the OpenShift Container Storage Operator and click Install.
  4. Select an Update Channel, Installation Mode, and Approval Strategy.
  5. Click Subscribe.

    On the Installed Operators page, the OpenShift Container Storage Operator appears in the openshift-storage project with the status Succeeded.

3.3.2.2. Creating the Multi-Cloud Object Gateway storage bucket

You can create the Multi-Cloud Object Gateway (MCG) storage bucket’s Custom Resources (CRs).

Procedure

  1. Log in to the OpenShift Container Platform cluster:

    $ oc login
  2. Create the NooBaa CR configuration file, noobaa.yml, with the following content:

    apiVersion: noobaa.io/v1alpha1
    kind: NooBaa
    metadata:
      name: noobaa
      namespace: openshift-storage
    spec:
     dbResources:
       requests:
         cpu: 0.5 1
         memory: 1Gi
     coreResources:
       requests:
         cpu: 0.5 2
         memory: 1Gi
    1 2
    For a very small cluster, you can change the cpu value to 0.1.
  3. Create the NooBaa object:

    $ oc create -f noobaa.yml
  4. Create the BackingStore CR configuration file, bs.yml, with the following content:

    apiVersion: noobaa.io/v1alpha1
    kind: BackingStore
    metadata:
      finalizers:
      - noobaa.io/finalizer
      labels:
        app: noobaa
      name: mcg-pv-pool-bs
      namespace: openshift-storage
    spec:
      pvPool:
        numVolumes: 3 1
        resources:
          requests:
            storage: 50Gi 2
        storageClass: gp2 3
      type: pv-pool
    1
    Specify the number of volumes in the PV pool.
    2
    Specify the size of the volumes.
    3
    Specify the storage class.
  5. Create the BackingStore object:

    $ oc create -f bs.yml
  6. Create the BucketClass CR configuration file, bc.yml, with the following content:

    apiVersion: noobaa.io/v1alpha1
    kind: BucketClass
    metadata:
      labels:
        app: noobaa
      name: mcg-pv-pool-bc
      namespace: openshift-storage
    spec:
      placementPolicy:
        tiers:
        - backingStores:
          - mcg-pv-pool-bs
          placement: Spread
  7. Create the BucketClass object:

    $ oc create -f bc.yml
  8. Create the ObjectBucketClaim CR configuration file, obc.yml, with the following content:

    apiVersion: objectbucket.io/v1alpha1
    kind: ObjectBucketClaim
    metadata:
      name: migstorage
      namespace: openshift-storage
    spec:
      bucketName: migstorage 1
      storageClassName: openshift-storage.noobaa.io
      additionalConfig:
        bucketclass: mcg-pv-pool-bc
    1
    Record the bucket name for adding the replication repository to the CAM web console.
  9. Create the ObjectBucketClaim object:

    $ oc create -f obc.yml
  10. Watch the resource creation process to verify that the ObjectBucketClaim status is Bound:

    $ watch -n 30 'oc get -n openshift-storage objectbucketclaim migstorage -o yaml'

    This process can take five to ten minutes.

  11. Obtain and record the following values, which are required when you add the replication repository to the CAM web console:

    • S3 endpoint:

      $ oc get route -n openshift-storage s3
    • S3 provider access key:

      $ oc get secret -n openshift-storage migstorage -o go-template='{{ .data.AWS_ACCESS_KEY_ID }}' | base64 -d
    • S3 provider secret access key:

      $ oc get secret -n openshift-storage migstorage -o go-template='{{ .data.AWS_SECRET_ACCESS_KEY }}' | base64 -d

3.3.3. Configuring an AWS S3 storage bucket as a replication repository

You can configure an AWS S3 storage bucket as a replication repository.

Prerequisites

  • The AWS S3 storage bucket must be accessible to the source and target clusters.
  • You must have the AWS CLI installed.
  • If you are using the snapshot copy method:

    • You must have access to EC2 Elastic Block Storage (EBS).
    • The source and target clusters must be in the same region.
    • The source and target clusters must have the same storage class.
    • The storage class must be compatible with snapshots.

Procedure

  1. Create an AWS S3 bucket:

    $ aws s3api create-bucket \
        --bucket <bucket_name> \ 1
        --region <bucket_region> 2
    1
    Specify your S3 bucket name.
    2
    Specify your S3 bucket region, for example, us-east-1.
  2. Create the IAM user velero:

    $ aws iam create-user --user-name velero
  3. Create an EC2 EBS snapshot policy:

    $ cat > velero-ec2-snapshot-policy.json <<EOF
    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Effect": "Allow",
                "Action": [
                    "ec2:DescribeVolumes",
                    "ec2:DescribeSnapshots",
                    "ec2:CreateTags",
                    "ec2:CreateVolume",
                    "ec2:CreateSnapshot",
                    "ec2:DeleteSnapshot"
                ],
                "Resource": "*"
            }
        ]
    }
    EOF
  4. Create an AWS S3 access policy for one or for all S3 buckets:

    $ cat > velero-s3-policy.json <<EOF
    {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Effect": "Allow",
                "Action": [
                    "s3:GetObject",
                    "s3:DeleteObject",
                    "s3:PutObject",
                    "s3:AbortMultipartUpload",
                    "s3:ListMultipartUploadParts"
                ],
                "Resource": [
                    "arn:aws:s3:::<bucket_name>/*" 1
                ]
            },
            {
                "Effect": "Allow",
                "Action": [
                    "s3:ListBucket",
                    "s3:GetBucketLocation",
                    "s3:ListBucketMultipartUploads"
                ],
                "Resource": [
                    "arn:aws:s3:::<bucket_name>" 2
                ]
            }
        ]
    }
    EOF
    1 2
    To grant access to a single S3 bucket, specify the bucket name. To grant access to all AWS S3 buckets, specify * instead of a bucket name:
    "Resource": [
        "arn:aws:s3:::*"
  5. Attach the EC2 EBS policy to velero:

    $ aws iam put-user-policy \
      --user-name velero \
      --policy-name velero-ebs \
      --policy-document file://velero-ec2-snapshot-policy.json
  6. Attach the AWS S3 policy to velero:

    $ aws iam put-user-policy \
      --user-name velero \
      --policy-name velero-s3 \
      --policy-document file://velero-s3-policy.json
  7. Create an access key for velero:

    $ aws iam create-access-key --user-name velero
    {
      "AccessKey": {
            "UserName": "velero",
            "Status": "Active",
            "CreateDate": "2017-07-31T22:24:41.576Z",
            "SecretAccessKey": <AWS_SECRET_ACCESS_KEY>, 1
            "AccessKeyId": <AWS_ACCESS_KEY_ID> 2
        }
    }
    1 2
    Record the AWS_SECRET_ACCESS_KEY and the AWS_ACCESS_KEY_ID for adding the AWS repository to the CAM web console.

3.3.4. Configuring a Google Cloud Provider storage bucket as a replication repository

You can configure a Google Cloud Provider (GCP) storage bucket as a replication repository.

Prerequisites

  • The GCP storage bucket must be accessible to the source and target clusters.
  • You must have gsutil installed.
  • If you are using the snapshot copy method:

    • The source and target clusters must be in the same region.
    • The source and target clusters must have the same storage class.
    • The storage class must be compatible with snapshots.

Procedure

  1. Run gsutil init to log in:

    $ gsutil init
    Welcome! This command will take you through the configuration of gcloud.
    
    Your current configuration has been set to: [default]
    
    To continue, you must login. Would you like to login (Y/n)?
  2. Set the BUCKET variable:

    $ BUCKET=<bucket_name> 1
    1
    Specify your bucket name.
  3. Create a storage bucket:

    $ gsutil mb gs://$BUCKET/
  4. Set the PROJECT_ID variable to your active project:

    $ PROJECT_ID=$(gcloud config get-value project)
  5. Create a velero service account:

    $ gcloud iam service-accounts create velero \
        --display-name "Velero Storage"
  6. Set the SERVICE_ACCOUNT_EMAIL variable to the service account’s email address:

    $ SERVICE_ACCOUNT_EMAIL=$(gcloud iam service-accounts list \
      --filter="displayName:Velero Storage" \
      --format 'value(email)')
  7. Grant permissions to the service account:

    $ ROLE_PERMISSIONS=(
        compute.disks.get
        compute.disks.create
        compute.disks.createSnapshot
        compute.snapshots.get
        compute.snapshots.create
        compute.snapshots.useReadOnly
        compute.snapshots.delete
        compute.zones.get
    )
    
    gcloud iam roles create velero.server \
        --project $PROJECT_ID \
        --title "Velero Server" \
        --permissions "$(IFS=","; echo "${ROLE_PERMISSIONS[*]}")"
    
    gcloud projects add-iam-policy-binding $PROJECT_ID \
        --member serviceAccount:$SERVICE_ACCOUNT_EMAIL \
        --role projects/$PROJECT_ID/roles/velero.server
    
    gsutil iam ch serviceAccount:$SERVICE_ACCOUNT_EMAIL:objectAdmin gs://${BUCKET}
  8. Save the service account’s keys to the credentials-velero file in the current directory:

    $ gcloud iam service-accounts keys create credentials-velero \
      --iam-account $SERVICE_ACCOUNT_EMAIL

3.3.5. Configuring a Microsoft Azure Blob storage container as a replication repository

You can configure a Microsoft Azure Blob storage container as a replication repository.

Prerequisites

  • You must have an Azure storage account.
  • You must have the Azure CLI installed.
  • The Azure Blob storage container must be accessible to the source and target clusters.
  • If you are using the snapshot copy method:

    • The source and target clusters must be in the same region.
    • The source and target clusters must have the same storage class.
    • The storage class must be compatible with snapshots.

Procedure

  1. Set the AZURE_RESOURCE_GROUP variable:

    $ AZURE_RESOURCE_GROUP=Velero_Backups
  2. Create an Azure resource group:

    $ az group create -n $AZURE_RESOURCE_GROUP --location <CentralUS> 1
    1
    Specify your location.
  3. Set the AZURE_STORAGE_ACCOUNT_ID variable:

    $ AZURE_STORAGE_ACCOUNT_ID=velerobackups
  4. Create an Azure storage account:

    $ az storage account create \
      --name $AZURE_STORAGE_ACCOUNT_ID \
      --resource-group $AZURE_RESOURCE_GROUP \
      --sku Standard_GRS \
      --encryption-services blob \
      --https-only true \
      --kind BlobStorage \
      --access-tier Hot
  5. Set the BLOB_CONTAINER variable:

    $ BLOB_CONTAINER=velero
  6. Create an Azure Blob storage container:

    $ az storage container create \
      -n $BLOB_CONTAINER \
      --public-access off \
      --account-name $AZURE_STORAGE_ACCOUNT_ID
  7. Create a service principal and credentials for velero:

    $ AZURE_SUBSCRIPTION_ID=`az account list --query '[?isDefault].id' -o tsv`
    $ AZURE_TENANT_ID=`az account list --query '[?isDefault].tenantId' -o tsv`
    $ AZURE_CLIENT_SECRET=`az ad sp create-for-rbac --name "velero" --role "Contributor" --query 'password' -o tsv`
    $ AZURE_CLIENT_ID=`az ad sp list --display-name "velero" --query '[0].appId' -o tsv`
  8. Save the service principal’s credentials in the credentials-velero file:

    $ cat << EOF  > ./credentials-velero
    AZURE_SUBSCRIPTION_ID=${AZURE_SUBSCRIPTION_ID}
    AZURE_TENANT_ID=${AZURE_TENANT_ID}
    AZURE_CLIENT_ID=${AZURE_CLIENT_ID}
    AZURE_CLIENT_SECRET=${AZURE_CLIENT_SECRET}
    AZURE_RESOURCE_GROUP=${AZURE_RESOURCE_GROUP}
    AZURE_CLOUD_NAME=AzurePublicCloud
    EOF

3.4. Migrating applications with the CAM web console

You can migrate application workloads by adding your clusters and replication repository to the CAM web console. Then, you can create and run a migration plan.

If your cluster or replication repository are secured with self-signed certificates, you can create a CA certificate bundle file or disable SSL verification.

3.4.1. Creating a CA certificate bundle file

If you use a self-signed certificate to secure a cluster or a replication repository, certificate verification might fail with the following error message: Certificate signed by unknown authority.

You can create a custom CA certificate bundle file and upload it in the CAM web console when you add a cluster or a replication repository.

Procedure

Download a CA certificate from a remote endpoint and save it as a CA bundle file:

$ echo -n | openssl s_client -connect <host_FQDN>:<port> \ 1
  | sed -ne '/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p' > <ca_bundle.cert> 2
1
Specify the host FQDN and port of the endpoint, for example, api.my-cluster.example.com:6443.
2
Specify the name of the CA bundle file.

3.4.2. Adding a cluster to the CAM web console

You can add a cluster to the CAM web console.

Prerequisites

If you are using Azure snapshots to copy data:

  • You must provide the Azure resource group name when you add the source cluster.
  • The source and target clusters must be in the same Azure resource group and in the same location.

Procedure

  1. Log in to the cluster.
  2. Obtain the service account token:

    $ oc sa get-token mig -n openshift-migration
    eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJtaWciLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlY3JldC5uYW1lIjoibWlnLXRva2VuLWs4dDJyIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6Im1pZyIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50LnVpZCI6ImE1YjFiYWMwLWMxYmYtMTFlOS05Y2NiLTAyOWRmODYwYjMwOCIsInN1YiI6InN5c3RlbTpzZXJ2aWNlYWNjb3VudDptaWc6bWlnIn0.xqeeAINK7UXpdRqAtOj70qhBJPeMwmgLomV9iFxr5RoqUgKchZRG2J2rkqmPm6vr7K-cm7ibD1IBpdQJCcVDuoHYsFgV4mp9vgOfn9osSDp2TGikwNz4Az95e81xnjVUmzh-NjDsEpw71DH92iHV_xt2sTwtzftS49LpPW2LjrV0evtNBP_t_RfskdArt5VSv25eORl7zScqfe1CiMkcVbf2UqACQjo3LbkpfN26HAioO2oH0ECPiRzT0Xyh-KwFutJLS9Xgghyw-LD9kPKcE_xbbJ9Y4Rqajh7WdPYuB0Jd9DPVrslmzK-F6cgHHYoZEv0SvLQi-PO0rpDrcjOEQQ
  3. Log in to the CAM web console.
  4. In the Clusters section, click Add cluster.
  5. Fill in the following fields:

    • Cluster name: May contain lower-case letters (a-z) and numbers (0-9). Must not contain spaces or international characters.
    • Url: URL of the cluster’s API server, for example, https://<master1.example.com>:8443.
    • Service account token: String that you obtained from the source cluster.
    • Azure cluster: Optional. Select it if you are using Azure snapshots to copy your data.
    • Azure resource group: This field appears if Azure cluster is checked.
    • If you use a custom CA bundle, click Browse and browse to the CA bundle file.
  6. Click Add cluster.

    The cluster appears in the Clusters section.

3.4.3. Adding a replication repository to the CAM web console

You can add an object storage bucket as a replication repository to the CAM web console.

Prerequisites

  • You must configure an object storage bucket for migrating the data.

Procedure

  1. Log in to the CAM web console.
  2. In the Replication repositories section, click Add repository.
  3. Select a Storage provider type and fill in the following fields:

    • AWS for AWS S3, MCG, and generic S3 providers:

      • Replication repository name: Specify the replication repository name in the CAM web console.
      • S3 bucket name: Specify the name of the S3 bucket you created.
      • S3 bucket region: Specify the S3 bucket region. Required for AWS S3. Optional for other S3 providers.
      • S3 endpoint: Specify the URL of the S3 service, not the bucket, for example, https://<s3-storage.apps.cluster.com>. Required for a generic S3 provider. You must use the https:// prefix.
      • S3 provider access key: Specify the <AWS_SECRET_ACCESS_KEY> for AWS or the S3 provider access key for MCG.
      • S3 provider secret access key: Specify the <AWS_ACCESS_KEY_ID> for AWS or the S3 provider secret access key for MCG.
      • Require SSL verification: Clear this check box if you are using a generic S3 provider.
      • If you use a custom CA bundle, click Browse and browse to the Base64-encoded CA bundle file.
    • GCP:

      • Replication repository name: Specify the replication repository name in the CAM web console.
      • GCP bucket name: Specify the name of the GCP bucket.
      • GCP credential JSON blob: Specify the string in the credentials-velero file.
    • Azure:

      • Replication repository name: Specify the replication repository name in the CAM web console.
      • Azure resource group: Specify the resource group of the Azure Blob storage.
      • Azure storage account name: Specify the Azure Blob storage account name.
      • Azure credentials - INI file contents: Specify the string in the credentials-velero file.
  4. Click Add repository and wait for connection validation.
  5. Click Close.

    The new repository appears in the Replication repositories section.

3.4.4. Changing migration plan limits for large migrations

You can change the migration plan limits for large migrations.

Important

Changes should first be tested in your environment to avoid a failed migration.

A single migration plan has the following default limits:

  • 10 namespaces

    If this limit is exceeded, the CAM web console displays a Namespace limit exceeded error and you cannot create a migration plan.

  • 100 Pods

    If the Pod limit is exceeded, the CAM web console displays a warning message similar to the following example: Plan has been validated with warning condition(s). See warning message. Pod limit: 100 exceeded, found: 104.

  • 100 persistent volumes

    If the persistent volume limit is exceeded, the CAM web console displays a similar warning message.

Procedure

  1. Edit the Migration controller CR:

    $ oc get migrationcontroller -n openshift-migration
    NAME AGE
    migration-controller 5d19h
    
    $ oc edit migrationcontroller -n openshift-migration
  2. Update the following parameters:

    [...]
    migration_controller: true
    
    # This configuration is loaded into mig-controller, and should be set on the
    # cluster where `migration_controller: true`
    mig_pv_limit: 100
    mig_pod_limit: 100
    mig_namespace_limit: 10
    [...]

3.4.5. Creating a migration plan in the CAM web console

You can create a migration plan in the CAM web console.

Prerequisites

  • The CAM web console must contain the following:

    • Source cluster
    • Target cluster, which is added automatically during the CAM tool installation
    • Replication repository
  • If you use snapshots to copy data, the source and target clusters must be running on the same cloud provider (AWS, GCP, or Azure) and in the same region.

Procedure

  1. Log in to the CAM web console.
  2. In the Plans section, click Add plan.
  3. Enter the Plan name and click Next.

    The Plan name can contain up to 253 lower-case alphanumeric characters (a-z, 0-9). It must not contain spaces or underscores (_).

  4. Select a Source cluster.
  5. Select a Target cluster.
  6. Select a Replication repository.
  7. Select the projects to be migrated and click Next.
  8. Select Copy or Move for the PVs:

    • Copy copies the data in a source cluster’s PV to the replication repository and then restores it on a newly created PV, with similar characteristics, in the target cluster.

      Optional: You can verify data copied with the filesystem method by selecting Verify copy. This option, which generates a checksum for each source file and checks it after restoration, significantly reduces performance.

    • Move unmounts a remote volume (for example, NFS) from the source cluster, creates a PV resource on the target cluster pointing to the remote volume, and then mounts the remote volume on the target cluster. Applications running on the target cluster use the same remote volume that the source cluster was using. The remote volume must be accessible to the source and target clusters.
  9. Click Next.
  10. Select a Copy method for the PVs:

    • Snapshot backs up and restores the disk using the cloud provider’s snapshot functionality. It is significantly faster than Filesystem.

      Note

      The storage and clusters must be in the same region and the storage class must be compatible.

    • Filesystem copies the data files from the source disk to a newly created target disk.
  11. Select a Storage class for the PVs.

    If you selected the Filesystem copy method, you can change the storage class during migration, for example, from Red Hat Gluster Storage or NFS storage to Red Hat Ceph Storage.

  12. Click Next.
  13. If you want to add a migration hook, click Add Hook and perform the following steps:

    1. Specify the name of the hook.
    2. Select Ansible playbook to use your own playbook or Custom container image for a hook written in another language.
    3. Click Browse to upload the playbook.
    4. Optional: If you are not using the default Ansible runtime image, specify your custom Ansible image.
    5. Specify the cluster on which you want the hook to run.
    6. Specify the service account name.
    7. Specify the namespace.
    8. Select the migration step at which you want the hook to run:

      • PreBackup: Before backup tasks are started on the source cluster
      • PostBackup: After backup tasks are complete on the source cluster
      • PreRestore: Before restore tasks are started on the target cluster
      • PostRestore: After restore tasks are complete on the target cluster
  14. Click Add.

    You can add up to four hooks to a migration plan, assigning each hook to a different migration step.

  15. Click Finish.
  16. Click Close.

    The migration plan appears in the Plans section.

3.4.6. Running a migration plan in the CAM web console

You can stage or migrate applications and data with the migration plan you created in the CAM web console.

Prerequisites

The CAM web console must contain the following:

  • Source cluster
  • Target cluster, which is added automatically during the CAM tool installation
  • Replication repository
  • Valid migration plan

Procedure

  1. Log in to the CAM web console on the target cluster.
  2. Select a migration plan.
  3. Click Stage to copy data from the source cluster to the target cluster without stopping the application.

    You can run Stage multiple times to reduce the actual migration time.

  4. When you are ready to migrate the application workload, click Migrate.

    Migrate stops the application workload on the source cluster and recreates its resources on the target cluster.

  5. Optional: In the Migrate window, you can select Do not stop applications on the source cluster during migration.
  6. Click Migrate.
  7. When the migration is complete, verify that the application migrated successfully in the OpenShift Container Platform web console:

    1. Click HomeProjects.
    2. Click the migrated project to view its status.
    3. In the Routes section, click Location to verify that the application is functioning, if applicable.
    4. Click WorkloadsPods to verify that the Pods are running in the migrated namespace.
    5. Click StoragePersistent volumes to verify that the migrated persistent volume is correctly provisioned.

3.5. Troubleshooting

You can view the migration Custom Resources (CRs) and download logs to troubleshoot a failed migration.

If the application was stopped during the failed migration, you must roll it back manually in order to prevent data corruption.

Note

Manual rollback is not required if the application was not stopped during migration, because the original application is still running on the source cluster.

3.5.1. Viewing migration Custom Resources

The Cluster Application Migration (CAM) tool creates the following Custom Resources (CRs):

migration architecture diagram

20 MigCluster (configuration, CAM cluster): Cluster definition

20 MigStorage (configuration, CAM cluster): Storage definition

20 MigPlan (configuration, CAM cluster): Migration plan

The MigPlan CR describes the source and target clusters, repository, and namespace(s) being migrated. It is associated with 0, 1, or many MigMigration CRs.

Note

Deleting a MigPlan CR deletes the associated MigMigration CRs.

20 BackupStorageLocation (configuration, CAM cluster): Location of Velero backup objects

20 VolumeSnapshotLocation (configuration, CAM cluster): Location of Velero volume snapshots

20 MigMigration (action, CAM cluster): Migration, created during migration

A MigMigration CR is created every time you stage or migrate data. Each MigMigration CR is associated with a MigPlan CR.

20 Backup (action, source cluster): When you run a migration plan, the MigMigration CR creates two Velero backup CRs on each source cluster:

  • Backup CR #1 for Kubernetes objects
  • Backup CR #2 for PV data

20 Restore (action, target cluster): When you run a migration plan, the MigMigration CR creates two Velero restore CRs on the target cluster:

  • Restore CR #1 (using Backup CR #2) for PV data
  • Restore CR #2 (using Backup CR #1) for Kubernetes objects

Procedure

  1. Get the CR name:

    $ oc get <migration_cr> -n openshift-migration 1
    1
    Specify the migration CR, for example, migmigration.

    The output is similar to the following:

    NAME                                   AGE
    88435fe0-c9f8-11e9-85e6-5d593ce65e10   6m42s
  2. View the CR:

    $ oc describe <migration_cr> <88435fe0-c9f8-11e9-85e6-5d593ce65e10> -n openshift-migration

    The output is similar to the following examples.

MigMigration example

name:         88435fe0-c9f8-11e9-85e6-5d593ce65e10
namespace:    openshift-migration
labels:       <none>
annotations:  touch: 3b48b543-b53e-4e44-9d34-33563f0f8147
apiVersion:  migration.openshift.io/v1alpha1
kind:         MigMigration
metadata:
  creationTimestamp:  2019-08-29T01:01:29Z
  generation:          20
  resourceVersion:    88179
  selfLink:           /apis/migration.openshift.io/v1alpha1/namespaces/openshift-migration/migmigrations/88435fe0-c9f8-11e9-85e6-5d593ce65e10
  uid:                 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
spec:
  migPlanRef:
    name:        socks-shop-mig-plan
    namespace:   openshift-migration
  quiescePods:  true
  stage:         false
status:
  conditions:
    category:              Advisory
    durable:               True
    lastTransitionTime:  2019-08-29T01:03:40Z
    message:               The migration has completed successfully.
    reason:                Completed
    status:                True
    type:                  Succeeded
  phase:                   Completed
  startTimestamp:         2019-08-29T01:01:29Z
events:                    <none>

Velero backup CR #2 example (PV data)

apiVersion: velero.io/v1
kind: Backup
metadata:
  annotations:
    openshift.io/migrate-copy-phase: final
    openshift.io/migrate-quiesce-pods: "true"
    openshift.io/migration-registry: 172.30.105.179:5000
    openshift.io/migration-registry-dir: /socks-shop-mig-plan-registry-44dd3bd5-c9f8-11e9-95ad-0205fe66cbb6
  creationTimestamp: "2019-08-29T01:03:15Z"
  generateName: 88435fe0-c9f8-11e9-85e6-5d593ce65e10-
  generation: 1
  labels:
    app.kubernetes.io/part-of: migration
    migmigration: 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
    migration-stage-backup: 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
    velero.io/storage-location: myrepo-vpzq9
  name: 88435fe0-c9f8-11e9-85e6-5d593ce65e10-59gb7
  namespace: openshift-migration
  resourceVersion: "87313"
  selfLink: /apis/velero.io/v1/namespaces/openshift-migration/backups/88435fe0-c9f8-11e9-85e6-5d593ce65e10-59gb7
  uid: c80dbbc0-c9f8-11e9-95ad-0205fe66cbb6
spec:
  excludedNamespaces: []
  excludedResources: []
  hooks:
    resources: []
  includeClusterResources: null
  includedNamespaces:
  - sock-shop
  includedResources:
  - persistentvolumes
  - persistentvolumeclaims
  - namespaces
  - imagestreams
  - imagestreamtags
  - secrets
  - configmaps
  - pods
  labelSelector:
    matchLabels:
      migration-included-stage-backup: 8886de4c-c9f8-11e9-95ad-0205fe66cbb6
  storageLocation: myrepo-vpzq9
  ttl: 720h0m0s
  volumeSnapshotLocations:
  - myrepo-wv6fx
status:
  completionTimestamp: "2019-08-29T01:02:36Z"
  errors: 0
  expiration: "2019-09-28T01:02:35Z"
  phase: Completed
  startTimestamp: "2019-08-29T01:02:35Z"
  validationErrors: null
  version: 1
  volumeSnapshotsAttempted: 0
  volumeSnapshotsCompleted: 0
  warnings: 0

Velero restore CR #2 example (Kubernetes resources)

apiVersion: velero.io/v1
kind: Restore
metadata:
  annotations:
    openshift.io/migrate-copy-phase: final
    openshift.io/migrate-quiesce-pods: "true"
    openshift.io/migration-registry: 172.30.90.187:5000
    openshift.io/migration-registry-dir: /socks-shop-mig-plan-registry-36f54ca7-c925-11e9-825a-06fa9fb68c88
  creationTimestamp: "2019-08-28T00:09:49Z"
  generateName: e13a1b60-c927-11e9-9555-d129df7f3b96-
  generation: 3
  labels:
    app.kubernetes.io/part-of: migration
    migmigration: e18252c9-c927-11e9-825a-06fa9fb68c88
    migration-final-restore: e18252c9-c927-11e9-825a-06fa9fb68c88
  name: e13a1b60-c927-11e9-9555-d129df7f3b96-gb8nx
  namespace: openshift-migration
  resourceVersion: "82329"
  selfLink: /apis/velero.io/v1/namespaces/openshift-migration/restores/e13a1b60-c927-11e9-9555-d129df7f3b96-gb8nx
  uid: 26983ec0-c928-11e9-825a-06fa9fb68c88
spec:
  backupName: e13a1b60-c927-11e9-9555-d129df7f3b96-sz24f
  excludedNamespaces: null
  excludedResources:
  - nodes
  - events
  - events.events.k8s.io
  - backups.velero.io
  - restores.velero.io
  - resticrepositories.velero.io
  includedNamespaces: null
  includedResources: null
  namespaceMapping: null
  restorePVs: true
status:
  errors: 0
  failureReason: ""
  phase: Completed
  validationErrors: null
  warnings: 15

3.5.2. Downloading migration logs

You can download the Velero, Restic, and Migration controller logs in the CAM web console to troubleshoot a failed migration.

Procedure

  1. Log in to the CAM console.
  2. Click Plans to view the list of migration plans.
  3. Click the Options menu kebab of a specific migration plan and select Logs.
  4. Click Download Logs to download the logs of the Migration controller, Velero, and Restic for all clusters.
  5. To download a specific log:

    1. Specify the log options:

      • Cluster: Select the source, target, or CAM host cluster.
      • Log source: Select Velero, Restic, or Controller.
      • Pod source: Select the Pod name, for example, controller-manager-78c469849c-v6wcf

        The selected log is displayed.

        You can clear the log selection settings by changing your selection.

    2. Click Download Selected to download the selected log.

Optionally, you can access the logs by using the CLI, as in the following example:

$ oc get pods -n openshift-migration | grep controller
controller-manager-78c469849c-v6wcf           1/1     Running     0          4h49m

$ oc logs controller-manager-78c469849c-v6wcf -f -n openshift-migration

3.5.3. Error messages

3.5.3.1. Restic timeout error message in the Velero Pod log

If a migration fails because Restic times out, the following error appears in the Velero Pod log:

level=error msg="Error backing up item" backup=velero/monitoring error="timed out waiting for all PodVolumeBackups to complete" error.file="/go/src/github.com/heptio/velero/pkg/restic/backupper.go:165" error.function="github.com/heptio/velero/pkg/restic.(*backupper).BackupPodVolumes" group=v1

The default value of restic_timeout is one hour. You can increase this parameter for large migrations, keeping in mind that a higher value may delay the return of error messages.

Procedure

  1. In the OpenShift Container Platform web console, navigate to OperatorsInstalled Operators.
  2. Click Cluster Application Migration Operator.
  3. In the MigrationController tab, click migration-controller.
  4. In the YAML tab, update the following parameter value:

    spec:
      restic_timeout: 1h 1
    1
    Valid units are h (hours), m (minutes), and s (seconds), for example, 3h30m15s.
  5. Click Save.

3.5.3.2. ResticVerifyErrors in the MigMigration Custom Resource

If data verification fails when migrating a PV with the filesystem data copy method, the following error appears in the MigMigration Custom Resource (CR):

status:
  conditions:
  - category: Warn
    durable: true
    lastTransitionTime: 2020-04-16T20:35:16Z
    message: There were verify errors found in 1 Restic volume restores. See restore `<registry-example-migration-rvwcm>`
      for details 1
    status: "True"
    type: ResticVerifyErrors 2
1
The error message identifies the Restore CR name.
2
ResticErrors also appears. ResticErrors is a general error warning that includes verification errors.
Note

A data verification error does not cause the migration process to fail.

You can check the target cluster’s Restore CR to identify the source of the data verification error.

Procedure

  1. Log in to the target cluster.
  2. View the Restore CR:

    $ oc describe <registry-example-migration-rvwcm> -n openshift-migration

    The output identifies the PV with PodVolumeRestore errors:

    status:
      phase: Completed
      podVolumeRestoreErrors:
      - kind: PodVolumeRestore
        name: <registry-example-migration-rvwcm-98t49>
        namespace: openshift-migration
      podVolumeRestoreResticErrors:
      - kind: PodVolumeRestore
        name: <registry-example-migration-rvwcm-98t49>
        namespace: openshift-migration
  3. View the PodVolumeRestore CR:

    $ oc describe <migration-example-rvwcm-98t49>

    The output identifies the Restic Pod that logged the errors:

      completionTimestamp: 2020-05-01T20:49:12Z
      errors: 1
      resticErrors: 1
    ...
      resticPod: <restic-nr2v5>
  4. View the Restic Pod log:

    $ oc logs -f restic-nr2v5

3.5.4. Manually rolling back a migration

If your application was stopped during a failed migration, you must roll it back manually in order to prevent data corruption in the PV.

This procedure is not required if the application was not stopped during migration, because the original application is still running on the source cluster.

Procedure

  1. On the target cluster, switch to the migrated project:

    $ oc project <project>
  2. Get the deployed resources:

    $ oc get all
  3. Delete the deployed resources to ensure that the application is not running on the target cluster and accessing data on the PVC:

    $ oc delete <resource_type>
  4. To stop a DaemonSet without deleting it, update the nodeSelector in the YAML file:

    apiVersion: apps/v1
    kind: DaemonSet
    metadata:
      name: hello-daemonset
    spec:
      selector:
          matchLabels:
            name: hello-daemonset
      template:
        metadata:
          labels:
            name: hello-daemonset
        spec:
          nodeSelector:
            role: worker 1
    1
    Specify a nodeSelector value that does not exist on any node.
  5. Update each PV’s reclaim policy so that unnecessary data is removed. During migration, the reclaim policy for bound PVs is Retain, to ensure that data is not lost when an application is removed from the source cluster. You can remove these PVs during rollback.

    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv0001
    spec:
      capacity:
        storage: 5Gi
      accessModes:
        - ReadWriteOnce
      persistentVolumeReclaimPolicy: Retain 1
      ...
    status:
      ...
    1
    Specify Recycle or Delete.
  6. On the source cluster, switch to the migrated project and get its deployed resources:

    $ oc project <project>
    $ oc get all
  7. Start one or more replicas of each deployed resource:

    $ oc scale --replicas=1 <resource_type>/<resource_name>
  8. Update the nodeSelector of a DaemonSet to its original value, if you changed it during the procedure.

3.5.5. Gathering data for a customer support case

If you open a customer support case, you can run the must-gather tool with the openshift-migration-must-gather-rhel8 image to collect information about your cluster and upload it to the Red Hat Customer Portal.

The openshift-migration-must-gather-rhel8 image collects logs and Custom Resource data that are not collected by the default must-gather image.

Procedure

  1. Navigate to the directory where you want to store the must-gather data.
  2. Run the oc adm must-gather command:

    $ oc adm must-gather --image=registry.redhat.io/rhcam-1-2/openshift-migration-must-gather-rhel8

    The must-gather tool collects the cluster information and stores it in a must-gather.local.<uid> directory.

  3. Remove authentication keys and other sensitive information from the must-gather data.
  4. Create an archive file containing the contents of the must-gather.local.<uid> directory:

    $ tar cvaf must-gather.tar.gz must-gather.local.<uid>/

    You can attach the compressed file to your customer support case on the Red Hat Customer Portal.

3.5.6. Known issues

This release has the following known issues:

  • During migration, the Cluster Application Migration (CAM) tool preserves the following namespace annotations:

    • openshift.io/sa.scc.mcs
    • openshift.io/sa.scc.supplemental-groups
    • openshift.io/sa.scc.uid-range

      These annotations preserve the UID range, ensuring that the containers retain their file system permissions on the target cluster. There is a risk that the migrated UIDs could duplicate UIDs within an existing or future namespace on the target cluster. (BZ#1748440)

  • If an AWS bucket is added to the CAM web console and then deleted, its status remains True because the MigStorage CR is not updated. (BZ#1738564)
  • Most cluster-scoped resources are not yet handled by the CAM tool. If your applications require cluster-scoped resources, you may have to create them manually on the target cluster.
  • If a migration fails, the migration plan does not retain custom PV settings for quiesced pods. You must manually roll back the migration, delete the migration plan, and create a new migration plan with your PV settings. (BZ#1784899)
  • If a large migration fails because Restic times out, you can increase the restic_timeout parameter value (default: 1h) in the Migration controller CR.
  • If you select the data verification option for PVs that are migrated with the filesystem copy method, performance is significantly slower. Velero generates a checksum for each file and checks it when the file is restored.

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