Support for using Cluster Labels in AddonTemplate

[suresh-j2]

As part of AddonTemplate, it would be great to have read the values from Cluster Labels.

For example, if I set some hostname in managed cluster label, as part of addon manager, I can read that label key and use it while applying manifest.

This way, we can use the variable name and may be use cluster specific value also.

[qiujian16]

/assign @zhujian7

[zhujian7]

@suresh-j2 do you mean using variables in the addontemplates and getting the value from cluster labels, like this?

apiVersion: cluster.open-cluster-management.io/v1
kind: ManagedCluster
metadata:
  labels:
    region: us-east-1  # label
  name: cluster1
spec:
  hubAcceptsClient: true
  leaseDurationSeconds: 60

we want to use the label region in addonTemplate like:

apiVersion: addon.open-cluster-management.io/v1alpha1
kind: AddOnTemplate
metadata:
  name: my-addon-template
spec:
  addonName: my-addon
  agentSpec:
    workload:
      manifests:
      - apiVersion: v1
        kind: ConfigMap
        metadata:
          name: my-addon-configmap
        data:
          region: {{ region }} # or maybe {{ managedcluster.labels.region }}