Re-update WordPress and MySQL PV doc to use apps/v1beta2 APIs

Author: crimsonfaith91

cn/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/mysql-deployment.yaml

@@ -25,13 +25,17 @@ spec:
     requests:
       storage: 20Gi
 ---
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1beta2
 kind: Deployment
 metadata:
   name: wordpress-mysql
   labels:
     app: wordpress
 spec:
+  selector:
+    matchLabels:
+      app: wordpress
+      tier: mysql
   strategy:
     type: Recreate
   template:

cn/docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/wordpress-deployment.yaml

@@ -25,13 +25,17 @@ spec:
     requests:
       storage: 20Gi
 ---
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1beta2
 kind: Deployment
 metadata:
   name: wordpress
   labels:
     app: wordpress
 spec:
+  selector:
+    matchLabels:
+      app: wordpress
+      tier: frontend
   strategy:
     type: Recreate
   template:

docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/mysql-deployment.yaml

@@ -25,13 +25,17 @@ spec:
     requests:
       storage: 20Gi
 ---
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1beta2
 kind: Deployment
 metadata:
   name: wordpress-mysql
   labels:
     app: wordpress
 spec:
+  selector:
+    matchLabels:
+      app: wordpress
+      tier: mysql
   strategy:
     type: Recreate
   template:

docs/tutorials/stateful-application/mysql-wordpress-persistent-volume/wordpress-deployment.yaml

@@ -25,13 +25,17 @@ spec:
     requests:
       storage: 20Gi
 ---
-apiVersion: extensions/v1beta1
+apiVersion: apps/v1beta2
 kind: Deployment
 metadata:
   name: wordpress
   labels:
     app: wordpress
 spec:
+  selector:
+    matchLabels:
+      app: wordpress
+      tier: frontend
   strategy:
     type: Recreate
   template: