Paul Bastide

OpenShift 4.21.0: Using rhel-coreos-10 nodes

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Paul Bastide

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With OpenShift 4.21.0, you will see two new entries in the release payload for rhel-coreos-10 and rhel-coreos-10-extensions. These are node images for RHEL 10. This capability is a DevPreview/Tech Preview, and will be available as a stable/generally available feature in a future release.

An example of the release payload entry:

rhel-coreos-10                                 quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:ca2fc3c3f56da0772fe6d428b78c4ce4ed36afaf9cc5a71f6c310ffb1673772a
rhel-coreos-10-extensions                      quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:077b897ed0cd007ed9b88762d6834fcfc0b9508538ddc9df1dbc0917231e45fc

Note, there is a limitation that you use RHEL10 nodes with Power 10 or Power 11 based systems.

You can create a new MachineConfigPool with the name rhel10 using Multi-Architecture Compute: Supporting Architecture Specific Operating System and Kernel Parameters. The matchExpression applies the worker and rhel10 MachineConfig objects to the MachineConfigPool members. The members are determined based on the matchLabels.

cat <<EOF | oc apply -f -
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfigPool
metadata:
  name: rhel10
spec:
  machineConfigSelector:
    matchExpressions:
      - {key: machineconfiguration.openshift.io/role, operator: In, values: [worker,rhel10]}
  nodeSelector:
    matchLabels:
      node-role.kubernetes.io/rhel10: ""
EOF

Verify the power MachineConfigPool is created.

Find the rhel-coreos image

oc adm release info --image-for rhel-coreos

Now that the rhel10 MachineConfigPool is created.

cat <<EOF | oc apply -f -
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: rhel10
  name: 99-override-image-rhel10
spec:
  osImageURL: "quay.io/openshift-release-dev/ocp-v4.0-art-dev@sha256:ca2fc3c3f56da0772fe6d428b78c4ce4ed36afaf9cc5a71f6c310ffb1673772a"
EOF

You have seen how to use RHEL10 nodes with OpenShift on IBM Power.

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