Set default imagePullPolicy to IfNotPresent (#325)

* Set default imagePullPolicy to IfNotPresent

Fixes #295 for MySQL chart in the same way as #309 does it for MariaDB.

Related to kubernetes/kubernetes#38542.

PS I've changed `pod.alpha.kubernetes.io/init-containers` to
`pod.beta.kubernetes.io/init-containers`.

* Update docs about updating images

stable/mysql/Chart.yaml

@@ -1,5 +1,5 @@
 name: mysql
-version: 0.2.2
+version: 0.2.3
 description: Chart for MySQL
 keywords:
 - mysql

stable/mysql/README.md

@@ -47,7 +47,7 @@ The following tables lists the configurable parameters of the MySQL chart and th
 | Parameter                  | Description                        | Default                                                    |
 | -----------------------    | ---------------------------------- | ---------------------------------------------------------- |
 | `imageTag`                 | `mysql` image tag.                 | Most recent release                                        |
-| `imagePullPolicy`          | Image pull policy                  | `Always` if `imageTag` is `latest`, else `IfNotPresent`    |
+| `imagePullPolicy`          | Image pull policy                  | `IfNotPresent`                                             |
 | `mysqlRootPassword`        | Password for the `root` user.      | `nil`                                                      |
 | `mysqlUser`                | Username of new user to create.    | `nil`                                                      |
 | `mysqlPassword`            | Password for the new user.         | `nil`                                                      |

stable/mysql/templates/deployment.yaml

@@ -13,7 +13,7 @@ spec:
       labels:
         app: {{ template "fullname" . }}
       annotations:
-        pod.alpha.kubernetes.io/init-containers: '[
+        pod.beta.kubernetes.io/init-containers: '[
               {
                   "name": "remove-lost-found",
                   "image": "busybox:1.25.0",
@@ -23,14 +23,15 @@ spec:
                           "name": "data",
                           "mountPath": "/var/lib/mysql"
                       }
-                  ]
+                  ],
+                  "imagePullPolicy": {{ .Values.imagePullPolicy | quote }}
               }
           ]'
     spec:
       containers:
       - name: {{ template "fullname" . }}
         image: "mysql:{{ .Values.imageTag }}"
-        imagePullPolicy: {{ default "" .Values.imagePullPolicy | quote }}
+        imagePullPolicy: {{ .Values.imagePullPolicy | quote }}
         resources:
 {{ toYaml .Values.resources | indent 10 }}
         env:

stable/mysql/values.yaml

@@ -21,11 +21,11 @@ imageTag: "5.7.14"
 ##
 # mysqlDatabase:
 
-## Specify a imagePullPolicy
-## 'Always' if imageTag is 'latest', else set to 'IfNotPresent'
-## ref: http://kubernetes.io/docs/user-guide/images/#pre-pulling-images
+## Specify an imagePullPolicy (Required)
+## It's recommended to change this to 'Always' if the image tag is 'latest'
+## ref: http://kubernetes.io/docs/user-guide/images/#updating-images
 ##
-# imagePullPolicy:
+imagePullPolicy: IfNotPresent
 
 ## Persist data to a persitent volume
 persistence: