Suppose, I have several Kubernetes clusters and I have some namespaces in each of them.
Some of these namespaces are labeled project: a and others project: b.
Now I want to ensure that resources in namespaces labeled project: a can communicate with each other, but not with something else, same for the other projects.
If it was just one Kubernetes cluster, then I would simply use NetworkPolicies.
However, I would like to connect the clusters somehow and to ensure that this restriction applies also when the resources are spread in many clusters.