Upgrading Red Hat OpenShift Container Platform

Upgrade your Red Hat® OpenShift® Container Platform when the version is no longer supported by Cloud Pak for Business Automation.

Before you begin

Before you start the upgrade of Red Hat OpenShift Container Platform, make sure that you take a backup so that you can recover from any upgrade issues. For more information, see Backing up your environments .

The Red Hat OpenShift Container Platform version 4.18 is the minimum version for Cloud Pak for Business Automation 26.0.0. If the Red Hat OpenShift Container Platform version is 4.18.xx, the xx is the security or bug fix part of the version. It is recommended to apply the latest security or bug fixes for a specific Red Hat OpenShift Container Platform version.

Attention: Before you begin the upgrade of the OpenShift cluster, make sure that all the standby EDB Postgres cluster members are up and running.

Under normal circumstances, an EDB Postgres cluster can manage if one member is down, but it is not ideal just before you start an OpenShift upgrade. The status of the EDB cluster can be checked in the EDB Postgres CR.

For more information about EDB Postgres maintenance on Kubernetes, see the EDB Postgres documentation External link opens a new window or tab .

About this task

When you need to upgrade your OpenShift Container Platform, make sure that you refer to the steps that are needed for the cluster that contains Cloud Pak for Business Automation.

Note: The previous Red Hat OpenShift upgrade process transitions through all the Red Hat OpenShift versions. For example, if you needed to upgrade Red Hat OpenShift from 4.16 to 4.18, then you need to upgrade to each Red Hat OpenShift version step by step (4.16 -> 4.17 -> 4.18). However, Red Hat now supports an Extended Update Support (EUS) upgrade from 4.16 -> 4.18, see Red Hat OpenShift EUS Overview External link opens a new window or tab .

Each upgrade can take a few hours, so plan for the entire upgrade. The expectation is that if you upgrade to an intermediate version (odd versions), and you complete the upgrade within a reasonable time frame. Ideally, the cluster does not run on an intermediate version indefinitely.

The Red Hat OpenShift Container Platform Update Graph External link opens a new window or tab Update Path tile to access the tool, and you do need Red Hat customer account credentials to use it.

Procedure

  1. Go to IBM Cloud Pak® for Business Automation detailed system requirements External link opens a new window or tab Cloud Pak for Business Automation version. Click the Containers tab on this report to see the supported minor OpenShift Container Platform releases for the given Cloud Pak for Business Automation version. It also includes any Cloud Pak for Business Automation interim fix requirements for a specific OpenShift Container Platform version.
    Note:  If your current OpenShift Container Platform version is too old for your Cloud Pak for Business Automation version, then upgrade your OpenShift Container Platform before you upgrade Cloud Pak for Business Automation. If your Cloud Pak for Business Automation installation is too old for the OpenShift Container Platform version, then upgrade Cloud Pak for Business Automation.
  2. Various Postgres deployments have a PodDisruptionBudget (PDB) with minimum available set to 1. If the replica size is also set to 1, then it can prevent nodes from restarting automatically. If a node restart is blocked, it can prevent the completion of the OpenShift Container Platform upgrade or other cluster configuration tasks.

    To mitigate the problem, scale down the Postgres operator or delete the pods that are stuck.

    • Postgres deployments that have a PodDisruptionBudget (PDB).
      1. Scale down the postgresql-operator deployment to replica 0.
      2. Delete the PDB objects from the CP4BA namespace with minimum available set to 1. The PDB objects must be related to deployments owned by the cluster CR objects.
      3. Complete the OpenShift Container Platform upgrade.
      4. Scale the postgresql-operator operator back up to replica 1 after the upgrade.
    • When the nodes attempt to restart during the upgrade or configuration task, delete the pods from the Cloud Pak for Business Automation namespace that are stuck. The pods must be related to deployments owned by the cluster CR objects.