Chapter 9. Importing a target managed cluster to the hub cluster

You can import clusters from different Kubernetes cloud providers. After you import, the targeted cluster becomes a managed cluster for the Red Hat Advanced Cluster Management for Kubernetes hub cluster. Unless otherwise specified, complete the import tasks anywhere where you can access the hub cluster and the targeted managed cluster.

A hub cluster cannot manage any other hub cluster, but can manage itself. The hub cluster is configured to automatically be imported and self-managed. You do not need to manually import the hub cluster.

However, if you remove a hub cluster and try to import it again, you need to add the local-cluster:true label.

Choose from the following instructions to set up your managed cluster, either from the console or from the CLI:

Required user type or access level: Cluster administrator

9.1. Importing an existing cluster with the console

After you install Red Hat Advanced Cluster Management for Kubernetes, you are ready to import a cluster to manage. You can import from both the console and the CLI. Follow this procedure to import from the console. You need your terminal for authentication during this procedure.

9.1.1. Prerequisites

  • You need a Red Hat Advanced Cluster Management for Kubernetes hub cluster that is deployed. If you are importing bare metal clusters, you must have the hub cluster installed on Red Hat OpenShift Container Platform version 4.4, or later.
  • You need a cluster that you want to manage and Internet connectivity.
  • Install kubectl. To install kubectl, see Install and Set Up kubectl in the Kubernetes documentation.
  • You need the base64 command line tool.

Required user type or access level: Cluster administrator

9.1.2. Importing a cluster

You can import existing clusters from the Red Hat Advanced Cluster Management for Kubernetes console for each of the available cloud providers.

Note: A hub cluster cannot manage a different hub cluster. A hub cluster is set up to automatically import and manage itself, so you do not have to manually import a hub cluster to manage itself.

  1. From the navigation menu, hover over Automate infrastructure and click Clusters.
  2. Click Add cluster.
  3. Click Import an existing cluster.
  4. Provide a cluster name. By default, the namespace is set to the same value as your cluster name. Best practice: Leave the namespace value and do not edit.
  5. Optional: Click to expand Edit cluster import YAML file and modify the endpoint configuration.

    See Table 1. YAML file parameters and descriptions for details about each parameter.

  6. Optional: After you import, you can add labels by clicking Configure advanced parameters and use these labels to search.
  7. Optional: Configure the MANAGED CLUSTER URLS. By configuring the MANAGED CLUSTER URLS, the URLs display in the table when you run the oc get managedcluster command.

    1. If it is not already on, turn on the YAML content using the switch in the web console so you can view the content.
    2. Add the manageClusterClientConfigs section to the ManagedCluster spec in the import.yaml file, as shown in the following example:

      apiVersion: cluster.open-cluster-management.io/v1
      kind: ManagedCluster
      metadata:
        labels:
          cloud: auto-detect
      	vendor: auto-detect
      	name: cluster-test
        name: cluster-test
      spec:
        hubAcceptsClient: true
        managedClusterClientConfigs:
        - url: https://multicloud-console.apps.new-managed.dev.redhat.com
      ---
      apiVersion: agent.open-cluster-management.io/v1
      ...

      Replace the URL value is the external access URL address of the managed cluster.

  8. Click Generate Command to retrieve the command to deploy the open-cluster-management-agent-addon.
  9. From the Import an existing cluster window, hover and click the Copy command icon to copy the import command and the token that you are provided. You must click the Copy icon to receive the accurate copy. Important: The command contains pull secret information that is copied to each of the imported clusters. Anyone who can access the imported clusters can also view the pull secret information. Consider creating a secondary pull secret at https://cloud.redhat.com/ or by creating a service account so your personal credentials are not compromised. See Using image pull secrets or Understanding and creating service accounts for more information.
  10. From your terminal, authenticate to your managed cluster. Configure your kubectl for your targeted managed cluster.

    See Supported clouds to learn how to configure your kubectl.

  11. To deploy the open-cluster-management-agent-addon to the managed cluster, run the command that you generated and copied from step 8.
  12. Click View cluster to view the Overview page and a summary of your cluster.

Note: You can continue to import more clusters. Click Import another to repeat the process.

9.1.2.1. YAML parameters and descriptions

Table 1: The following table lists the parameters and descriptions that are available in the YAML file:

ParameterDescriptionDefault value

clusterLabels

Provide cluster labels; you can add labels to your file

none

clusterLabels.cloud

The provider label for your cluster

auto-detect

clusterLabels.vendor

The Kubernetes vendor label for your cluster

auto-detect

clusterLabels.environment

The environment label for your cluster

none

clusterLabels.region

The region where your cluster is set up

none

applicationManager.enabled

Enables multicluster manager application deployment, deploys subscription controller and deployable controller

true

searchCollector.enabled

Enables search collection and indexing

true

policyController.enabled

Enable the Governance and risk dashboard policy feature

true, updateInterval: 15

certPolicyController.enabled

Monitors certificate expiration based on distributed policies

true

iamPolicyController

Monitors identity controls based on distributed policies

true

serviceRegistry.enabled

Service registry that is used to discover services that are deployed by Application Deployable among managed clusters.

false

serviceRegistry.dnsSuffix

The suffix of the registry DNS name, which is added to the end of the target clusters dns domain name.

mcm.svc

serviceRegistry.plugins

Comma-separated list of enabled plugins. Supported plugins: kube-service, kube-ingress, and istio.

kube-service

version

Version of open-cluster-management-agent-addon

2.1.0

9.1.3. Removing an imported cluster

Complete the following procedure to remove an imported cluster and the open-cluster-management-agent-addon that was created on the managed cluster.

  1. From the Clusters page, find your imported cluster in the table.
  2. Click Actions > Detach cluster to remove your cluster from management.

Note: If you attempt to detach the hub cluster, which is named local-cluster, be aware that the default setting of disableHubSelfManagement is false. This setting causes the hub cluster to reimport itself and manage itself when it is detached and it reconciles the MultiClusterHub controller. It might take hours for the hub cluster to complete the detachment process and reimport. If you want to reimport the hub cluster without waiting for the processes to finish, you can enter the following command to restart the multiclusterhub-operator pod and reimport faster:

oc delete po -n open-cluster-management `oc get pod -n open-cluster-management | grep multiclusterhub-operator| cut -d' ' -f1`

You can change the value of the hub cluster to not import automatically by changing the disableHubSelfManagement value to true, as described in Installing while connected online.

9.2. Importing a managed cluster with the CLI

After you install Red Hat Advanced Cluster Management for Kubernetes, you are ready to import a cluster to manage. You can import from both the console and the CLI. Follow this procedure to import from the CLI.

Important: A hub cluster cannot manage a different hub cluster. A hub cluster is set up to automatically import and manage itself. You do not have to manually import a hub cluster to manage itself.

However, if you remove a hub cluster and try to import it again, you need to add the local-cluster:true label.

9.2.1. Prerequisites

  • You need a Red Hat Advanced Cluster Management for Kubernetes hub cluster that is deployed. If you are importing bare metal clusters, you must have the hub cluster installed on Red Hat OpenShift Container Platform version 4.5, or later.
  • You need a separate cluster that you want to manage and Internet connectivity.
  • You need the Red Hat OpenShift Container Platform CLI version 4.3, or later, to run oc commands. See Getting started with the CLI for information about installing and configuring the Red Hat OpenShift CLI, oc.
  • You need to install the Kubernetes CLI, kubectl. To install kubectl, see Install and Set Up kubectl in the Kubernetes documentation.

    Note: Download the installation file for CLI tools from the console.

9.2.2. Supported architecture

  • Linux
  • macOS

9.2.3. Prepare for import

  1. Log in to your hub cluster. Run the following command:

    oc login
  2. Run the following command on the hub cluster to create the namespace. Note: The cluster name that is defined in <cluster_name> is also used as the cluster namespace in the .yaml file file and commands:

    oc new-project ${CLUSTER_NAME}
    oc label namespace ${CLUSTER_NAME} cluster.open-cluster-management.io/managedCluster=${CLUSTER_NAME}
  3. Edit the example ManagedCluster with the following sample of YAML:

    apiVersion: cluster.open-cluster-management.io/v1
    kind: ManagedCluster
    metadata:
      name: <cluster_name>
    spec:
      hubAcceptsClient: true
  4. Save the file as managed-cluster.yaml.
  5. Apply the YAML file with the following command:

    oc apply -f managed-cluster.yaml
  6. Create the klusterlet addon configuration file. Enter the following example YAML:

    apiVersion: agent.open-cluster-management.io/v1
    kind: KlusterletAddonConfig
    metadata:
      name: <cluster_name>
      namespace: <cluster_name>
    spec:
      clusterName: <cluster_name>
      clusterNamespace: <cluster_name>
      applicationManager:
        enabled: true
      certPolicyController:
        enabled: true
      clusterLabels:
        cloud: auto-detect
        vendor: auto-detect
      iamPolicyController:
        enabled: true
      policyController:
        enabled: true
      searchCollector:
        enabled: true
      version: 2.1.0
  7. Save the file as klusterlet-addon-config.yaml.
  8. Apply the YAML. Run the following command:

    oc apply -f klusterlet-addon-config.yaml

The ManagedCluster-Import-Controller will generate a secret named ${CLUSTER_NAME}-import. The ${CLUSTER_NAME}-import secret contains the import.yaml that the user applies to a managed cluster to install klusterlet.

9.2.4. Importing the klusterlet

Important: The import command contains pull secret information that is copied to each of the imported clusters. Anyone who can access the imported clusters can also view the pull secret information.

  1. Obtain the klusterlet-crd.yaml that was generated by the managed cluster import controller.

    Run the following command:

    oc get secret ${CLUSTER_NAME}-import -n ${CLUSTER_NAME} -o jsonpath={.data.crds\\.yaml} | base64 --decode > klusterlet-crd.yaml
  2. Obtain the import.yaml that was generated by the managed cluster import controller. Run the following command:

    oc get secret ${CLUSTER_NAME}-import -n ${CLUSTER_NAME} -o jsonpath={.data.import\\.yaml} | base64 --decode > import.yaml
  3. Log in to your target managed cluster.
  4. Apply the klusterlet-crd.yaml that was generated in step 1. Run the following command:

    kubectl apply -f klusterlet-crd.yaml
  5. Apply the import.yaml file that was generated in step 2. Run the following command:

    kubectl apply -f import.yaml
  6. Validate the pod status on the target managed cluster. Run the following command:

    kubectl get pod -n open-cluster-management-agent
  7. Validate JOINED and AVAILABLE status for your imported cluster. Run the following command from the hub cluster:

    kubectl get managedcluster ${CLUSTER_NAME}
  8. Addons will be installed after the managed cluster is AVAILABLE. Validate the pod status of addons on the target managed cluster. Run the following command:

    kubectl get pod -n open-cluster-management-agent-addon

9.3. Modifying the klusterlet addons settings of your cluster

You can modify the settings of klusterlet addon to change your configuration using the hub cluster.

The klusterlet addon controller manages the functions that are enabled and disabled according to the settings in the klusterletaddonconfigs.agent.open-cluster-management.io Kubernetes resource.

The following settings can be updated in the klusterletaddonconfigs.agent.open-cluster-management.io Kubernetes resource:

Setting nameValue

applicationmanager

true or false

policyController

true or false

searchCollector

true or false

certPolicyController

true or false

iamPolicyController

true or false

9.3.1. Modify using the console on the hub cluster

You can modify the settings of the klusterletaddonconfigs.agent.open-cluster-management.io resource by using the hub cluster. Complete the following steps to change the settings:

  1. Authenticate into the Red Hat Advanced Cluster Management for Kubernetes console of the hub cluster.
  2. From the main menu of the hub cluster console, select Search.
  3. In the search parameters, enter the following value: kind:klusterletaddonconfigs
  4. Select the endpoint resource that you want to update.
  5. Find the spec section and select Edit to edit the content.
  6. Modify your settings.
  7. Select Save to apply your changes.

9.3.2. Modify using the command line on the hub cluster

You must have access to the <cluster-name> namespace to modify your settings by using the hub cluster. Complete the following steps:

  1. Authenticate into the hub cluster.
  2. Enter the following command to edit the resource:

    kubectl edit klusterletaddonconfigs.agent.open-cluster-management.io <cluster-name> -n <cluster-name>
  3. Find the spec section.
  4. Modify your settings, as necessary.