Fix PVC in loki helm

[cbcoutinho]

The lacking apiVersion and kind attributes make ArgoCD go into an endless loop

What this PR does / why we need it:

The PVC lacks attributes which are applied by Kubernetes; however, this leaves ArgoCD in a loop because the attributes are different.

Which issue(s) this PR fixes: Fixes #

Special notes for your reviewer:

Checklist

• [ ] Reviewed the CONTRIBUTING.md guide (required)
• [ ] Documentation added
• [ ] Tests updated
• [ ] Title matches the required conventional commits format, see here
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• [ ] Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
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[cbcoutinho]

This is the diff that ArgoCD detects when I use PVCs for the loki-chunks-cache StatefulSet - it tries to prune the fields that ArgoCD generates from the helm chart.

The only workaround I've found is to use the following stanza in my Application manifest for ArgoCD, ignoring those fields:

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: observability
  namespace: argocd
spec:
  project: ...
  ignoreDifferences:
    - group: apps
      kind: StatefulSet
      name: observability-loki-chunks-cache
      jqPathExpressions:
        - .spec.volumeClaimTemplates[].apiVersion
        - .spec.volumeClaimTemplates[].kind
  sources:
    - repoURL: https://grafana.github.io/helm-charts
      chart: loki
      targetRevision: 6.12.0

The persistence is enabled for the loki-chunks-cache by selecting the storage class in the values.yml file

chunksCache:
  # Persistence settings for the chunks-cache
  persistence:
    enabled: true # TODO: Endless loop
    storageClass: nfs-client

[cbcoutinho]

Hi @chaudum, I confirmed that al the persistent volume claims required by loki components appear to have this issue, so I currently have to add the ignoreDifferences block for each StatefulSet deployed via helm. For the singleBinarry installation with caching enabled, this requires the initial loki volume, as well as volumes for the chunks-cache and results-cache

[aslafy-z]

https://github.com/grafana/loki/pull/15192 should have fixed it.

[Starefossen]

Yes, this can be closed now.

[JStickler]

Closing, fixed via https://github.com/grafana/loki/pull/15192. Thank you for taking the time to contribute to the Loki project.