[stable/minio] Add subpath for /export volume (#2534)

* feat(stable/minio): add subpath for /export volume

Conditionally adds the subPath for the /export volume mount.
Works only if `persistence.enabled` is true and `persistence.subPath`
is not empty string.

This is handy in cases where the volume plugin doesn't
support sub folder mounting. GlusterFS plugin, for example doesn't support
it whereas NFS actually does.

* docs(stable/minio): add subPath to Configuration table

* chore(stable/minio): version bump

* chore(stable/minio): another version bump to keep ahead of master

stable/minio/README.md

@@ -89,6 +89,7 @@ The following tables lists the configurable parameters of the Minio chart and th
 | `persistence.size`         | Size of persistent volume claim     | `10Gi`                                                  |
 | `persistence.storageClass` | Type of persistent volume claim     | `generic`                                               |
 | `persistence.accessMode`   | ReadWriteOnce or ReadOnly           | `ReadWriteOnce`                                         |
+| `persistence.subPath`      | Mount a sub directory of the persistent volume if set | `""`                                  |
 | `resources`                | CPU/Memory resource requests/limits | Memory: `256Mi`, CPU: `100m`                            |
 | `nodeSelector`             | Node labels for pod assignment      | `{}`                                                    |
 | `defaultBucket.enabled`    | If true, a bucket will be created after minio

stable/minio/templates/minio_deployment.yaml

@@ -60,6 +60,9 @@ spec:
           volumeMounts:
             - name: export
               mountPath: {{ .Values.mountPath }}
+              {{- if and .Values.persistence.enabled .Values.persistence.subPath }}
+              subPath: "{{ .Values.persistence.subPath }}"
+              {{- end }}
             - name: minio-server-config
               mountPath: {{ default "/root/.minio/" .Values.configPath | quote }}
             - name: podinfo

stable/minio/templates/minio_statefulset.yaml

@@ -77,6 +77,9 @@ spec:
           volumeMounts:
             - name: export
               mountPath: {{ .Values.mountPath }}
+              {{- if and .Values.persistence.enabled .Values.persistence.subPath }}
+              subPath: "{{ .Values.persistence.subPath }}"
+              {{- end }}
             - name: minio-server-config
               mountPath: {{ default "/root/.minio/" .Values.configPath | quote }}
             - name: podinfo

stable/minio/values.yaml

@@ -39,6 +39,11 @@ persistence:
   accessMode: ReadWriteOnce
   size: 10Gi
 
+  ## If subPath is set mount a sub folder of a volume instead of the root of the volume.
+  ## This is especially handy for volume plugins that don't natively support sub mounting (like glusterfs).
+  ##
+  subPath: ""
+
 ## Expose the Minio service to be accessed from outside the cluster (LoadBalancer service).
 ## or access it from within the cluster (ClusterIP service). Set the service type and the port to serve it.
 ## ref: http://kubernetes.io/docs/user-guide/services/