Chapter 9. Troubleshooting

This section provides information for troubleshooting common migration issues.

9.1. Architecture

This section describes MTV custom resources, services, and workflows.

9.1.1. MTV custom resources and services

The Migration Toolkit for Virtualization (MTV) is provided as an OpenShift Container Platform Operator. It creates and manages the following custom resources (CRs) and services.

MTV custom resources

  • Provider CR stores attributes that enable MTV to connect to and interact with the source and target providers.
  • NetworkMapping CR maps the networks of the source and target providers.
  • StorageMapping CR maps the storage of the source and target providers.
  • Provisioner CR stores the configuration of the storage provisioners, such as supported volume and access modes.
  • Plan CR contains a list of VMs with the same migration parameters and associated network and storage mappings.

  • Migration CR runs a migration plan.

    Only one Migration CR per migration plan can run at a given time. You can create multiple Migration CRs for a single Plan CR.

MTV services

  • The Inventory service performs the following actions:

    • Connects to the source and target providers.
    • Maintains a local inventory for mappings and plans.
    • Stores VM configurations.
    • Runs the Validation service if a VM configuration change is detected.
  • The Validation service checks the suitability of a VM for migration by applying rules.

  • The User Interface service performs the following actions:

    • Enables you to create and configure MTV CRs.
    • Displays the status of the CRs and the progress of a migration.

  • The Migration Controller service orchestrates migrations.

    When you create a migration plan, the Migration Controller service validates the plan and adds a status label. If the plan fails validation, the plan status is Not ready and the plan cannot be used to perform a migration. If the plan passes validation, the plan status is Ready and it can be used to perform a migration. After a successful migration, the Migration Controller service changes the plan status to Completed.

  • The Kubevirt Controller and Containerized Data Import (CDI) Controller services handle most technical operations.

9.1.2. High-level migration workflow

The high-level workflow shows the migration process from the point of view of the user:

  1. You create a source provider, a target provider, a network mapping, and a storage mapping.

  2. You create a Plan custom resource (CR) that includes the following resources:

    • Source provider
    • Target provider, if MTV is not installed on the target cluster
    • Network mapping
    • Storage mapping
    • One or more virtual machines (VMs)

  3. You run a migration plan by creating a Migration CR that references the Plan CR.

    If you cannot migrate all the VMs for any reason, you can create multiple Migration CRs for the same Plan CR until all VMs are migrated.

  4. For each VM in the Plan CR, the Migration Controller service creates a VirtualMachine CR and records the VM migration progress in the Migration CR.

    When all VMs have been migrated, the Migration Controller service updates the status of the Plan CR to Completed. The power state of each source VM is maintained after migration.

9.1.3. Detailed migration workflow

You can use the detailed migration workflow to troubleshoot a failed migration.

The workflow describes the following steps:

  1. When you create a Migration custom resource (CR) to run a migration plan, the Migration Controller service creates a VirtualMachine CR for each source virtual machine (VM) and a DataVolume CR for each source VM disk.

    For each VM disk:

  2. The Containerized Data Importer (CDI) Controller service creates a persistent volume claim (PVC) based on the parameters specified in the DataVolume CR.
  3. If the StorageClass has a dynamic provisioner, the persistent volume (PV) is dynamically provisioned by the StorageClass provisioner.
  4. The CDI Controller service creates an importer pod.

  5. The importer pod streams the VM disk to the PV.

    After the VM disks are transferred:

  6. The Migration Controller service creates a conversion pod with the PVCs attached to it.

    The conversion pod runs virt-v2v, which installs and configures device drivers on the PVCs of the target VM.

  7. When the target VM is powered on, the KubeVirt Controller service creates a virt-launcher pod and a VirtualMachineInstance CR.

    The virt-launcher pod runs QEMU-KVM with the PVCs attached as VM disks.

9.2. Logs and custom resources

You can download logs and custom resource (CR) information for troubleshooting. For more information, see the detailed migration workflow.

9.2.1. Collected logs and custom resource information

You can download logs and custom resource (CR) yaml files for the following targets by using the MTV web console or the command line interface (CLI):

  • Migration plan: Web console or CLI.
  • Virtual machine: Web console or CLI.
  • Namespace: CLI only.

The must-gather tool collects the following logs and CR files in an archive file:

  • CRs:

    • DataVolume CR: Represents a disk mounted on a migrated VM.
    • VirtualMachine CR: Represents a migrated VM.
    • Plan CR: Defines the VMs and storage and network mapping.

  • Logs:

    • importer pod: Disk-to-data-volume conversion log. The importer pod naming convention is importer-<migration_plan>-<vm_id><5_char_id>, for example, importer-mig-plan-ed90dfc6-9a17-4a8btnfh, where ed90dfc6-9a17-4a8 is a truncated RHV VM ID and btnfh is the generated 5-character ID.
    • conversion pod: VM conversion log. The conversion pod runs virt-v2v, which installs and configures device drivers on the PVCs of the VM. The conversion pod naming convention is <migration_plan>-<vm_id><5_char_id>.
    • virt-launcher pod: VM launcher log. When a migrated VM is powered on, the virt-launcher pod runs QEMU-KVM with the PVCs attached as VM disks.
    • forklift-controller pod: The log is filtered for the migration plan, virtual machine, or namespace specified by the must-gather command.

    • forklift-must-gather-api pod: The log is filtered for the migration plan, virtual machine, or namespace specified by the must-gather command.

      Note

      Empty or excluded log files are not included in the must-gather archive file.

Example must-gather archive structure for a VMware migration plan

must-gather
└── namespaces
    ├── target-vm-ns
    │   ├── crs
    │   │   ├── datavolume
    │   │   │   ├── mig-plan-vm-7595-tkhdz.yaml
    │   │   │   ├── mig-plan-vm-7595-5qvqp.yaml
    │   │   │   └── mig-plan-vm-8325-xccfw.yaml
    │   │   └── virtualmachine
    │   │       ├── test-test-rhel8-2disks2nics.yaml
    │   │       └── test-x2019.yaml
    │   └── logs
    │       ├── importer-mig-plan-vm-7595-tkhdz
    │       │   └── current.log
    │       ├── importer-mig-plan-vm-7595-5qvqp
    │       │   └── current.log
    │       ├── importer-mig-plan-vm-8325-xccfw
    │       │   └── current.log
    │       ├── mig-plan-vm-7595-4glzd
    │       │   └── current.log
    │       └── mig-plan-vm-8325-4zw49
    │           └── current.log
    └── openshift-mtv
        ├── crs
        │   └── plan
        │       └── mig-plan-cold.yaml
        └── logs
            ├── forklift-controller-67656d574-w74md
            │   └── current.log
            └── forklift-must-gather-api-89fc7f4b6-hlwb6
                └── current.log

9.2.2. Downloading logs and custom resource information from the web console

You can download logs and information about custom resources (CRs) for a completed, failed, or canceled migration plan or for migrated virtual machines (VMs) by using the MTV web console.

Procedure

  1. In the web console, click Migration plans.
  2. Click Get logs beside a migration plan name.

  3. In the Get logs window, click Get logs.

    The logs are collected. A Log collection complete message is displayed.

  4. Click Download logs to download the archive file.
  5. To download logs for a migrated VM, click a migration plan name and then click Get logs beside the VM.

9.2.3. Accessing logs and custom resource information from the command line interface

You can access logs and information about custom resources (CRs) from the command line interface by using the must-gather tool. You must attach a must-gather data file to all customer cases.

You can gather data for a specific namespace, a completed, failed, or canceled migration plan, or a migrated virtual machine (VM) by using the filtering options.

Note

If you specify a non-existent resource in the filtered must-gather command, no archive file is created.

Prerequisites

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/migration-toolkit-virtualization/mtv-must-gather-rhel8:2.2.0

    The data is saved as /must-gather/must-gather.tar.gz. You can upload this file to a support case on the Red Hat Customer Portal.

  3. Optional: Run the oc adm must-gather command with the following options to gather filtered data:

    • Namespace: 

      $ oc adm must-gather --image=registry.redhat.io/migration-toolkit-virtualization/mtv-must-gather-rhel8:2.2.0 \
  -- NS=<namespace> /usr/bin/targeted

    • Migration plan: 

      $ oc adm must-gather --image=registry.redhat.io/migration-toolkit-virtualization/mtv-must-gather-rhel8:2.2.0 \
  -- PLAN=<migration_plan> /usr/bin/targeted

    • Virtual machine: 

      $ oc adm must-gather --image=registry.redhat.io/migration-toolkit-virtualization/mtv-must-gather-rhel8:2.2.0 \
  -- VM=<vm_name> NS=<namespace> /usr/bin/targeted 1
      1
      You must specify the VM name, not the VM ID, as it appears in the Plan CR.