Migrating existing cluster to Argo - some resources showing as missing

[pareeohnos]

We have 3 clusters running which were originally setup manually with Helm, and not using ArgoCD. We're now in the process of migrating out deployment process to GitOps, and I've setup ArgoCD on 2 of our 3 clusters. I'm now prepping our final cluster and everything is connected and ready to, but I've noticed that a few resources are showing up as missing which really shouldn't be.

I'm not sure if it's a limitation with Argo, Kubernetes, or something else but the three resources missing are

• PersistentVolume
• PriorityClass
• StorageClass

Checking on the cluster itself, I can find all three of these resources and their manifests are basically identical so I'm not sure why it's not picking them up.

Is there a reason Argo isn't picking these up? I don't want to simply sync everything and end up with issues, especially with the storage related resources so would be good to find a solution if anyone has any ideas?