Add an example for initContainer usage

Relates to #600.

Changelog.md

@@ -12,6 +12,7 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
  * Add the ability to set the `imagePullSecrets` for the operator statefulset.
  * Add Google Drive via service account as backup option.
  * Add `initBucketURL` and `initBucketSecretName` options to MysqlCluster chart. This bumps the chart version to `0.3.0`
+ * Add an example of how initContainers can be used to fix hostPath permissions.
 ### Changed
  * Only add `binlog-space-limit` for `percona` image
  * Make user-defined InitContainer take the precedence

examples/example-cluster.yaml

@@ -57,6 +57,19 @@ spec:
   #   tolerations: []
   #   priorityClassName:
   #   serviceAccountName: default
+  #   # Use a initContainer to fix the permissons of a hostPath volume.
+  #   initContainers:
+  #     - name: volume-permissions
+  #       image: busybox
+  #       securityContext:
+  #         runAsUser: 0
+  #       command:
+  #         - sh
+  #         - -c
+  #         - chmod 750 /data/mysql; chown 999:999 /data/mysql
+  #       volumeMounts:
+  #         - name: data
+  #           mountPath: /data/mysql
 
   ## Specify additional volume specification
   # volumeSpec: