Chapter 14. Managing cluster pools (Technology preview)

Cluster pools provide rapid and cost-effective access to configured Red Hat OpenShift Container Platform clusters on-demand and at scale. Cluster pools maintain a configurable and scalable number of OpenShift Container Platform clusters on Amazon Web Services, Google Cloud Platform, or Microsoft Azure in a hibernating state that can be claimed when they are needed. They are especially useful when providing or replacing cluster environments for development, continuous integration, and production scenarios.

ClusterClaim resources are used to check out clusters from cluster pools. After a cluster is checked out from a cluster pool, the checked out cluster is resumed and brought to a ready state. The cluster pool automatically creates a hibernated cluster in the cluster pool, to replace the claimed one.

Note: When a cluster that was claimed from the cluster pool is no longer needed and is destroyed, the resources are deleted. The cluster does not return to the cluster pool.

14.1. Creating a cluster pool

The procedure for creating a cluster pool is similar to the procedure for creating a cluster. Clusters in a cluster pool are not created for immediate use.

Required access: Administrator

14.1.1. Prerequisites

You must have the following prerequisites before creating a cluster pool:

  • A deployed Red Hat Advanced Cluster Management for Kubernetes hub cluster.
  • Internet access for your Red Hat Advanced Cluster Management for Kubernetes hub cluster so it can create the Kubernetes cluster on the provider environment.
  • An AWS, GCP, or Microsoft Azure provider credential. See Managing credentials overview for more information.
  • A configured domain in your provider environment. See your provider documentation for instructions about how to configure a domain.
  • Provider login credentials.
  • A OpenShift Container Platform image pull secret. See Using image pull secrets.

14.1.2. Create a cluster pool

To create a cluster pool, complete the following steps:

  1. From the navigation menu, click Infrastructure > Clusters.
  2. Select the Cluster pools tab to view cluster pools that you can access.
  3. Select Create cluster pool.
  4. Select the infrastructure provider for your cluster pool.
  5. Select the infrasctructure credential that you want to use for the cluster pool. You can create one by selecting Add credential, if it is not available in the list.
  6. Select Next to continue to the cluster pool details.
  7. Enter a name for your cluster pool.

  8. Enter the namespace where you want to create your cluster pool. You can select an existing namespace from the list, or type the name of a new one to create one. The cluster pool does not have to be in the same namespace as the clusters.

    When you create a cluster pool in a cluster set, the namespace admin permission is applied to all of the users with clusterset admin permissions for the namespace where you add the cluster pool. Similarly, the namespace view permission is applied to the users with clusterset view permissions.

  9. Optional: Select a cluster set name if you want the RBAC roles for your cluster pool to share the role assignments of an existing cluster set.

    Note: If you do not have cluster admin permissions, you must select a cluster set. The request to create a cluster set is rejected with a forbidden error if you do not include the cluster set name in this situation. If no cluster sets are available for you to select, contact your cluster administrator to create a cluster set and give you clusterset admin permissions to it.

  10. Enter the number of clusters that you want available in your cluster pool by adding the number to the cluster pool size.
  11. Select Next.

  12. Enter the required information in the remaining steps to complete to provision your cluster pool. The procedure from this point on is the same as the procedure for creating clusters.

    For specific information about the information that is required for your provider, see the following information:

  13. After all of the information is entered, select Create to create the cluster pool. After at least one cluster is available in the pool, a Claim cluster button appears.

14.2. Claiming clusters from cluster pools

ClusterClaim resources are used to check out clusters from cluster pools. After a cluster is checked out from a cluster pool, the checked out cluster is brought to a ready state. The cluster pool automatically creates a new hibernated cluster in the cluster pool to replace the claimed one.

Note: When a cluster that was claimed from the cluster pool is no longer needed and is destroyed, the resources are deleted. The cluster does not return to the cluster pool.

Required access: Administrator

14.2.1. Prerequisite

You must have the following available before claiming a cluster from a cluster pool:

A cluster pool with available clusters to claim. See Creating a cluster pool for information about how to create a cluster pool. If there are no available clusters to claim, the Claim cluster button is not displayed.

14.2.2. Claim the cluster from the cluster pool

To checkout a cluster from the cluster pool, resume the cluster and claim it as one of your managed clusters. Complete the following steps to claim a cluster:

  1. From the navigation menu, click Infrastructure > Clusters.
  2. Select the Cluster pools tab.
  3. Find the name of the cluster pool you want to claim a cluster from and select Claim cluster.
  4. Enter a cluster claim name to help identify the cluster.
  5. Select Claim.

The claimed cluster comes out of hibernation and appears in the Managed Cluster tab with a status of Resuming. After the cluster reaches a status of Ready, the cluster is available for use.

14.3. Scaling cluster pools

You can change the size of the cluster pool by increasing or decreasing the number of hibernating clusters in the cluster pool.

Required access: Cluster administrator

Complete the following steps to change the number of clusters in your cluster pool:

  1. From the navigation menu, click Infrastructure > Clusters.
  2. Select the Cluster pools tab.
  3. Find the name of the cluster pool in the Cluster pools table.
  4. In the Options menu for the cluster pool that you want to change, select Scale cluster pool.
  5. Increase or decrease the pool size by changing the value of the pool size.
  6. Select Scale to commit the change.

Your cluster pools are scaled to reflect your new values.

14.4. Updating the cluster pool release image

When the clusters in your cluster pool remain in hibernation for some time, the Red Hat OpenShift Container Platform release image of the clusters might become backlevel. If this happens, you can upgrade the version of the release image of the clusters that are in your cluster pool.

Required access: Edit

Complete the following steps to update the OpenShift Container Platform release image for the clusters in your cluster pool:

Note: This procedure does not update clusters from the cluster pool that are already claimed or hibernating in the cluster pool. After you complete this procedure. only clusters that are created and added to the cluster pool use the updated release image.

  1. From the navigation menu, click Infrastructure > Clusters.
  2. Select the Cluster pools tab.
  3. Find the name of the cluster pool that you want to update in the Cluster pools table.
  4. Click the Options menu to see the available options.
  5. Select Update release image.
  6. Select a new release image to use for future cluster creations from this cluster pool.
  7. Select Update to apply the selected release image.
  8. The cluster pool release image is updated.

Tip: You can update the release image for multiple cluster pools with one action by selecting the box for each of the the cluster pools and using the Actions menu to update the release image for the selected cluster pools.

14.5. Destroying a cluster pool

If you created a cluster pool and determine that you no longer need it, you can destroy the cluster pool. When you destroy a cluster pool, all of the unclaimed hibernating clusters are destroyed and their resources are released.

Required access: Cluster administrator

To destroy a cluster pool, complete the following steps:

  1. From the navigation menu, click Infrastructure > Clusters.
  2. Select the Cluster pools tab.
  3. Find the name of the cluster pool in the Cluster pools table.
  4. Click the Options menu to view the options for the cluster pool.
  5. Select Destroy cluster pool.
  6. Enter the name of the cluster pool to confirm.

  7. Select Destroy to remove the cluster pool. The clusters in the destroyed cluster pool are removed from the console while they are destroyed. It might take some time for all of the resources to be deleted after the clusters are removed from the console.

    When you destroy a cluster pool, you must manually delete its secrets. If you do not delete the secrets, creating a cluster pool with the same name and namespace fails because the new secrets collide with the existing secrets.

Tip: You can destroy multiple cluster pools with one action by selecting the box for each of the the cluster pools and using the Actions menu to destroy the selected cluster pools.

Your cluster pool is deleted.