As an update to my previous config of Crossplane with Argo CD, we can now configure Argo CD to use Annotations for sync tracking. This means we no longer have to configure resource ignore/deny rules per Composite Resource as we did with Label based tracking.

That said, I’m still undecided on XRC or XR as starting point for Crossplane in a GitOps pattern. Remove namespace boundary (that is a daydream at best for K8s multi-tenancy) by using vcluster, and you don’t need XRC. I’d personally throw XRC out the window and just use XR with vcluster. Makes the rest of this sort of irrelevant.

To configure Argo CD for Annotation resource tracking, edit the argocd-cm ConfigMap in the argocd Namespace (Argo CD version 2.4.8 or greater is recommended). Add application.resourceTrackingMethod: annotation to the data section as below:

apiVersion: v1
data:
  application.resourceTrackingMethod: annotation
kind: ConfigMap

On the next Argo CD sync, Crossplane Claims and Composite Resources will be considered synchronized and will not trigger auto-pruning. (Thanks @nabuskey for the heads up)