Resource annotation options for global resource customizations

[tafkam]

Summary

I would like to set resource annotations like

metadata:
  annotations:
      compare-options: IgnoreExtraneous
      sync-options: Prune=false
      hook-type: Skip

for resource groups on a global level like the "ignoreDifferences" option in argocd-cm.
Additionally a compare-option like "IgnoreMissing" for the resource itself would be nice to have.

Motivation

Using Appscode Stash for Backups/Restores of k8s volumes and workloads, I have prepared several apiVersion: stash.appscode.com/v1beta1 kind: RestoreSession manifests for each application.

Applying those "fire and forget" RestoreSession CRD manifests is usually not needed/wanted, hence a global "hook-type: Skip", so you can still start a restore with a selective sync, and sync the whole app without worrying to start a restore and potentially lose the data since the last backup.

Defining those "on a need basis" manifests in the ArgoCD App renders the whole app out-of-sync, which is not the desired behaviour. Using "IgnoreDifference=/" still renders the app as "out-of-sync", when the resource is not applied to the cluster. For this use-case rendering only the missing resource out-of-sync is the desired behaviour, so applied restore sessions can be tracked.

Proposal

• make annotated options globally available in resource.customizations
• create an option for the app sync-status to ignore a missing resource in the cluster

How do you think this should be implemented?