I am using helm to deploy StatefulSet, below is yaml

---
kind: StorageClass
apiVersion: storage.k8s.io/v1beta1
metadata:
  name: {{ .Values.database.mongo.storageClassName }}
  labels:
    for: for-mongo-statefulset
provisioner: kubernetes.io/gce-pd
parameters:
  type: pd-ssd
reclaimPolicy: Retain
---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: mongo
spec:
  serviceName: {{ .Values.database.mongo.serviceName }}
  replicas: {{ .Values.database.mongo.replicas }}
  template:
    metadata:
      labels:
        role: mongo
        environment: prod
    spec:
      serviceAccountName: {{ .Values.serviceAccount }}
      terminationGracePeriodSeconds: 10
      containers:
        - name: mongo
          image: mongo
          command:
            - mongod
            - "--bind_ip"
            - 0.0.0.0
            - "--replSet"
            - {{ .Values.database.mongo.replicaSet }}
            - "--smallfiles"
            - "--noprealloc"
          ports:
            - containerPort: {{ .Values.database.mongo.port }}
          volumeMounts:
            - name: {{ .Values.database.mongo.storageName }}
              mountPath: /data/db
        - name: mongo-sidecar
          image: cvallance/mongo-k8s-sidecar
          env:
            - name: MONGO_SIDECAR_POD_LABELS
              value: "role=mongo,environment=prod"
            - name: KUBERNETES_MONGO_SERVICE_NAME
              value: {{ .Values.database.mongo.serviceName }}
  volumeClaimTemplates:
  - metadata:
      name: {{ .Values.database.mongo.storageName }}
    spec:
      storageClassName: {{ .Values.database.mongo.storageClassName }}
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 100Gi

On helm install . -n release-name it creates StorageClass, PersistentVolume & PersistentVolumeClaim.

If I delete the release helm delete release-name --purge it keeps pv and pvc which is fine. But it deletes the StorageClass even though I have specified reclaimPolicy: Retain on sc.

Is this expected behaviour?

Helm version

Client: v2.10.0+g9ad53aa
Server: v2.10.0+g9ad53aa

Kubernetes version

Client Version: v1.11.1
Server Version: v1.9.7-gke.5

Update

I assumed reclaimPolicy was for both StorageClass and PV/PVC, Thanks to @Pablo for clearing my understanding regarding reclaimPolicy

Reclaim Policy

Persistent Volumes that are dynamically created by a storage class will have the reclaim policy specified in the reclaimPolicy field of the class, which can be either Delete or Retain. If no reclaimPolicy is specified when a StorageClass object is created, it will default to Delete

Is there anything similar to reclaimPolicy which will tell helm/kubernetes to not delete StorageClass when performing helm delete release-name --purge?