StatefulSet With One PVC Per Pod

The official StatefulSet example is curvine-csi/examples/statefulset-curvine.yaml in the Curvine source tree.

Use this pattern when each replica needs its own persistent directory instead of sharing one PVC.

Example ResourcesCopy Anchor Link

The example creates:

• Service/curvine-service
• StatefulSet/curvine-statefulset
• namespace curvine
• 3 replicas
• volumeClaimTemplates entry named data
• storageClassName: curvine-sc
• per-pod mount path /usr/share/nginx/html

Apply The ExampleCopy Anchor Link

kubectl apply -f curvine-csi/examples/statefulset-curvine.yaml

What HappensCopy Anchor Link

• Kubernetes creates one PVC per pod from volumeClaimTemplates.
• Each pod writes its hostname, timestamp, and PVC name into index.html.
• The CSI controller dynamically provisions a Curvine directory for each PVC.
• The CSI node plugin mounts each PVC into the matching pod.

Because each PVC is distinct, each pod gets independent application data even though all of them use the same CSI driver and StorageClass.

Verify PVC SeparationCopy Anchor Link

kubectl get statefulset -n curvine curvine-statefulset
kubectl get pods -n curvine -l app=curvine-stateful
kubectl get pvc -n curvine

Check the rendered content inside each replica:

for pod in curvine-statefulset-0 curvine-statefulset-1 curvine-statefulset-2; do
  echo "=== $pod ==="
  kubectl exec -n curvine "$pod" -- cat /usr/share/nginx/html/index.html
done

The output should differ by pod hostname and PVC name.

Check PersistenceCopy Anchor Link

kubectl exec -n curvine curvine-statefulset-0 -- sh -c 'echo retained >> /usr/share/nginx/html/index.html'
kubectl delete pod -n curvine curvine-statefulset-0
kubectl wait -n curvine --for=condition=Ready pod/curvine-statefulset-0 --timeout=120s
kubectl exec -n curvine curvine-statefulset-0 -- grep retained /usr/share/nginx/html/index.html

If retained is still present after the pod is recreated, the StatefulSet is correctly reusing the original PVC.

NotesCopy Anchor Link

• The example uses ReadWriteOnce in volumeClaimTemplates, which matches the common StatefulSet pattern of one writer per replica.
• The dynamically created Curvine directory is still derived from the StorageClass fs-path plus the generated PV name, not from the pod ordinal directly.
• FUSE reuse still happens at the node level based on master-addrs + fs-path; the pod-level data isolation comes from the subdirectory that each PVC points to.