ArgoCD: linkerd CRD out of sync

[ricsanfre]

Some Linkerd CRD are out-of-sync:

• authorizationpolicies.policy.linkerd.io
• meshtlsauthentications.policy.linkerd.io
• networkauthentications.policy.linkerd.io

In all cases, out of sync reason is caused by empty list value provided in field .spec.names.shortNames field: shortNames: []

In this cases, Kubernetes it is not keeping this empty field in its live manifest and so, it is always different from the desired one.

There is an open PR in linkerd (linkerd/linkerd2#10030) that will add shortNames to all these CRDs, so it might solve this issue.

[ricsanfre]

As indicated here: argoproj/argo-cd#11074 (comment), there is currently a limitation in Argo CD, only for CRDs, that avoids default values to be considered during diff calculation. This affects Argo CD Application status as it thinks it is out-of-sync when in fact it isn't.

There is no fix yet for the current CRD diff limitation for default values the suggested workaround is configuring ignoreDifference in the application level: https://argo-cd.readthedocs.io/en/stable/user-guide/diffing/

There is an enhancement proposal for solve this: argoproj/argo-cd#11139

[ricsanfre]

Issue solved upgrading to linkerd stable 2.13.3. PR linkerd/linkerd2#10030 is included and it solves the out-of-sync issue.