OpenShift Extended Update Support (EUS)

Something I recently learned from testing the EUS to EUS process, and I like to share the steps here. Starting OpenShift Container Platform (OCP) 4.12, Red hat is adding an additional 6 months of Extended Update Support (EUS) on even-numbered OCP release for the x86_64 architecture.

We can upgrade from a EUS version to the next EUS version with only a single reboot of non-control plane hosts. There are caveats that are listed in the reference section below.

Steps to upgrade from 4.10.x to 4.12 using the EUS-to-EUS upgrade

• Verify that all machine config pools display a status of Up to date and that no machine config pool displays a status of “UPDATING.”

• Set your channel to eus-<4.y+2>

• The channel is set to eus-4.12

• Pause all worker machine pools except for the master machine pool

• Update 4+1 only with Partial cluster update

• Wait for the partial upgrade to complete

• Make sure the partial update is completed

• No reboot for workers as noted that workers are paused on the K8S v 1.23

• Check the OCP console

• Check the KCS ​​https://access.redhat.com/articles/6955381. Review the k8s API version update and ensure the workloads are working properly and will be using the newly updated K8S API version.
• Execute the following command:
  oc -n openshift-config patch cm admin-acks --patch '{"data":{"ack-4.11-kube-1.25-api-removals-in-4.12":"true"}}' --type=merge
• OCP console shows

• Click resume all updates
• Double-check all machine pools. If updating, please wait for it to complete.

• Upgrade completed and now showing OCP 4.12 (K8S v1.25)

Reference:

• OpenShift Upgrade: https://docs.openshift.com/container-platform/4.12/updating/updating-cluster-prepare.html
• Prepare for EUS to EUS upgrade: https://docs.openshift.com/container-platform/4.12/updating/preparing-eus-eus-upgrade.html
• Red Hat OpenShift Extended Update Support (EUS): https://access.redhat.com/support/policy/updates/openshift-eus