How to get the resource ID of an ARO cluster?

Solution Verified - Updated -

Environment

  • Azure Red Hat OpenShift 4 (ARO)

Issue

  • How to check if an OpenShift cluster is ARO?
  • How to differentiate if a cluster is a Red Hat managed ARO cluster or a self-managed OCP cluster on Azure platform.

Resolution

An ARO cluster will have an Azure Resource ID that contains Microsoft.RedHatOpenShift on it , which looks like:

/subscriptions/$sub_id/resourceGroups/$rg/providers/Microsoft.RedHatOpenShift/openShiftClusters/$cluster_name

It is possible to get the Resource ID with the az CLI command:

$ az aro show -n [cluster_name] -g [rg_name] --query 'id'

Additional Information in the cluster for ARO clusters only

There is also some information in the cluster to check if it's an ARO cluster or not:

  • Existence of the ARO Custom Resource Definition (CRD) and getting the Resource ID from it (this resource is not collected by must-gather, so it's only available when checking the cluster):

    $ oc get cluster.aro.openshift.io cluster -o custom-columns=NAME:.metadata.name,RESOURCE_ID:.spec.resourceId
NAME      RESOURCE_ID
cluster   /subscriptions/$sub_id/resourceGroups/$rg/providers/Microsoft.RedHatOpenShift/openShiftClusters/$cluster_name

  • The configmap cluster-config-v1 in namespace kube-system show if the cluster is ARO (it can be shown in a must-gather):

    $ oc get cm cluster-config-v1 -n kube-system -o yaml
[...]
    platform:
      azure:
        aro: true
[...]
        image:
          offer: aro4
          publisher: azureopenshift
          sku: aro_48
[...]

Note: The steps below are valid for clusters that were initially installed at version 4.7 or later:

  • The configmap: openshift-install-manifests in namespace openshift-config has ARO in the invoker field (it can be shown in a must-gather):

    $ oc get cm openshift-install-manifests -n openshift-config -o yaml                                                                                                                
apiVersion: v1
data:
  invoker: ARO
[...]

Root Cause

An ARO cluster has an Azure Resource ID and also some resources indicating that the cluster is ARO.

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