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4. Deployment by default, StatefulSet opt-in

Date: 2026-06-24

Status​

Accepted

Context​

Upstream PR #89 proposed StatefulSet support. A registry backed by per-replica PersistentVolumes (via volumeClaimTemplates) is useful, but most installs use a single replica or shared object storage (S3/Azure/Swift) and a Deployment is the simpler, expected default. The PR as written also had defects (strategy instead of updateStrategy, a serviceName referencing service.name).

Decision​

Keep the Deployment as the default workload. Add useStatefulSet: false as an opt-in that swaps to a StatefulSet with volumeClaimTemplates. deployment.yaml renders only when useStatefulSet is false; statefulset.yaml only when true. The standalone PVC (pvc.yaml) is skipped in StatefulSet mode since the template provisions storage.

Fixes applied versus the upstream PR: use updateStrategy (valid for both kinds) and set serviceName to the chart fullname.

Consequences​

  • Existing installs are unaffected (default unchanged).
  • StatefulSet users get stable per-replica volumes.
  • Both paths share the same pod spec, probes, security context, and label helpers, so they stay in sync. Unit and integration tests cover both modes.