Use ARM architecture to run Keycloak on OpenShift

[ahus1]

Description

OpenShift with hosted control planes now supports ARM workers. Using such workers would be in-line with our company strategy.

Discussion

No response

Motivation

Save cloud costs both for us and our users

Details

No response

[ahus1]

The following worked succcessfully:

Create an ARM worker pool:

rosa create machinepool -c gh-keycloak-a --instance-type m6g.4xlarge --max-replicas 10 --min-replicas 1 --name scaling-arm --enable-autoscaling --autorepair

Add a scheduling to the keycloak.yaml to start Keycloak on the ARM workers:

  scheduling:
    affinity:
      nodeAffinity:
        requiredDuringSchedulingIgnoredDuringExecution:
          nodeSelectorTerms:
            - matchExpressions:
                - key: kubernetes.io/arch
                  operator: In
                  values:
                    - arm64
      podAffinity:
        preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 10
            podAffinityTerm:
              labelSelector:
                matchLabels:
                  app: keycloak
                  app.kubernetes.io/component: server
                  app.kubernetes.io/instance: keycloak
                  app.kubernetes.io/managed-by: keycloak-operator
              topologyKey: topology.kubernetes.io/zone
      podAntiAffinity:
        preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 50
            podAffinityTerm:
              labelSelector:
                matchLabels:
                  app: keycloak
                  app.kubernetes.io/component: server
                  app.kubernetes.io/instance: keycloak
                  app.kubernetes.io/managed-by: keycloak-operator
              topologyKey: kubernetes.io/hostname

I might have needed to kill a previously running pod. After that Keycloak started on the ARM pod.

Next steps:

• See what happens if we only have ARM workers in our cluster. Which services start? Do we then still need the schedule settings for Keycloak?
• We are building the image with the JDBC driver for AWS. How can we build such an image for ARM? Maybe adding a node selector for the build might be required to force the node - if source-to-image supports that.

    nodeSelector
      kubernetes.io/arch: arm64