Experimental Feature: ClusterResourceSet (beta)

The ClusterResourceSet feature is introduced to provide a way to automatically apply a set of resources (such as CNI/CSI) defined by users to matching newly-created/existing clusters.

Feature gate name: ClusterResourceSet

Variable name to enable/disable the feature gate: EXP_CLUSTER_RESOURCE_SET

The ClusterResourceSet feature is enabled by default, but can be disabled by setting the EXP_CLUSTER_RESOURCE_SET environment variable to false.

More details on ClusterResourceSet can be found at: ClusterResourceSet CAEP

Example

Suppose you want to automatically install the relevant external cloud provider on all workload clusters. This can be accomplished by labeling the clusters with the specific cloud (e.g. AWS, GCP or OpenStack) and then creating a ClusterResourceSet for each. For example, you could have the following for OpenStack:

apiVersion: addons.cluster.x-k8s.io/v1beta1
kind: ClusterResourceSet
metadata:
  name: cloud-provider-openstack
  namespace: default
spec:
  strategy: Reconcile
  clusterSelector:
    matchLabels:
      cloud: openstack
  resources:
    - name: cloud-provider-openstack
      kind: ConfigMap
    - name: cloud-config
      kind: Secret

This ClusterResourceSet would apply the content of the Secret cloud-config and of the ConfigMap cloud-provider-openstack in all workload clusters with the label cloud=openstack. Suppose you have the file cloud.conf that should be included in the Secret and cloud-provider-openstack.yaml that should be in the ConfigMap. The Secret and ConfigMap can then be created in the following way:

kubectl create secret generic cloud-config --from-file=cloud.conf --type=addons.cluster.x-k8s.io/resource-set
kubectl create configmap cloud-provider-openstack --from-file=cloud-provider-openstack.yaml

Note that it is required that the Secret has the type addons.cluster.x-k8s.io/resource-set for it to be picked up.

Update from ApplyOnce to Reconcile

The strategy field is immutable so existing CRS can’t be updated directly. However, CAPI won’t delete the managed resources in the target cluster when the CRS is deleted. So if you want to start using the Reconcile strategy, delete your existing CRS and create it again with the updated strategy.