Syncing a custom resource from one workspace to other in KCP

[Pankaj Thorat]

Hello Everyone,

I am writing a multi-cluster application and exploring the use of KCP in that context.

Specifically, I would like to understand whether KCP can support the following behavior. 

-       I have 2 workspaces where workspace workspace-1 maps to workload cluster cluster-1 and workspace workspace-2 maps to workload cluster cluster-2.

-       cluster-1 has k8s operator operator-1 that acts on an input custom resource CR-1 of type CRD-1 and generates a custom resource CR-2 of type CRD-2.

-       Cluster-2 has a k8s operator operator-2 that in turn acts on CR-2 of type CRD-2.

I want to know if there is any way for CR-2 to be shared from workspace-1 (cluster-1) to workspace-2 (cluster-2) via KCP transparent multi-cluster capabilities i.e. is it possible for KCP to be set up such that it can automatically share/sync CR-2 from workspace-1 (cluster-1) to workspace-2 (cluster-2)?

KCP steps envisaged are as follow: 

1.     Create 2 clusters in kind i.e. cluster-1 and cluster-2

$ kind create cluster -n cluster-1

$ kind create cluster -n cluster-2

$ kubectl config get-clusters

NAME

kind-cluster-1

kind-cluster-2

 

2.     Create 2 workspaces, where workspace-1 maps to cluster-1 and workspace-2 maps to cluster-2

$ kubectl ws ..

$ kubectl config use-context kind-cluster-1

$ kubectl ws create workspace-1

$ kubectl ws use workspace-1

$ kubectl kcp workload sync cluster-1 --syncer-image ghcr.io/kcp-dev/kcp/syncer:v0.10.0 -o cluster-1.yaml

$ KUBECONFIG=.kube/config kubectl apply -f cluster-1.yaml

 

$ kubectl ws ..

$ kubectl config use-context kind-cluster-2

$ kubectl ws create workspace-2

$ kubectl ws use workspace-2

$ kubectl kcp workload sync cluster-2 --syncer-image ghcr.io/kcp-dev/kcp/syncer:v0.10.0 -o cluster-2.yaml

$ KUBECONFIG=.kube/config kubectl apply -f cluster-2.yaml

 

3.     Deploy k8s operators operator-1 in cluster-1 and operator-2 in cluster-2

On cluster-1

$ kubectl create -f deploy/operator-1.yaml

On cluster-2

$ kubectl create -f deploy/operator-2.yaml

 

4.     KCP applies CR-1 in the cluster-1 (mapping to workspace-1), which triggers the business logic of operator-1 running in the cluster-1 to generate a new CR CR-2 on the cluster-1, which is getting synced back to the KCP in workspace-1 (we can check this by using kubectl get at the KCP host)

$ kubectl get CR-2

NAME                 AGE

CR-2                  45s

 

Is there any way to enable KCP to automatically deploy the CR object CR-2 on the workspace-2 (Cluster-2)?

Thank you very much in advance.

Regards,

Pankaj Thorat