StatefulSet 1.9 updates. (#6550)

* updates sts concept and tutorials to use 1.9 apps/v1

* Update statefulset.md

* clarify pod name label

docs/concepts/workloads/controllers/statefulset.md

@@ -10,8 +10,11 @@ title: StatefulSets
 ---
 
 {% capture overview %}
-**StatefulSet is the workload API object used to manage stateful applications.
-StatefulSets are beta in 1.8.**
+
+StatefulSet is the workload API object used to manage stateful applications.
+
+**Note:** StatefulSets are stable (GA) in 1.9.
+{: .note}
 
 {% glossary_definition term_id="statefulset" length="all" %}
 {% endcapture %}
@@ -66,7 +69,7 @@ spec:
   selector:
     app: nginx
 ---
-apiVersion: apps/v1beta2
+apiVersion: apps/v1
 kind: StatefulSet
 metadata:
   name: web
@@ -152,6 +155,12 @@ PersistentVolume Claims. Note that, the PersistentVolumes associated with the
 Pods' PersistentVolume Claims are not deleted when the Pods, or StatefulSet are deleted.
 This must be done manually.
 
+### Pod Name Label
+
+When the StatefulSet controller creates a Pod, it adds a label, `statefulset.kubernetes.io/pod-name`, 
+that is set to the name of the Pod. This label allows you to attach a Service to a specific Pod in 
+the StatefulSet.
+
 ## Deployment and Scaling Guarantees
 
 * For a StatefulSet with N replicas, when Pods are being deployed, they are created sequentially, in order from {0..N-1}.

docs/tasks/run-application/mysql-statefulset.yaml

@@ -1,4 +1,4 @@
-apiVersion: apps/v1beta2 # for versions before 1.8.0 use apps/v1beta1
+apiVersion: apps/v1
 kind: StatefulSet
 metadata:
   name: mysql

docs/tutorials/stateful-application/cassandra/cassandra-statefulset.yaml

@@ -1,4 +1,4 @@
-apiVersion: apps/v1beta2
+apiVersion: apps/v1
 kind: StatefulSet
 metadata:
   name: cassandra

docs/tutorials/stateful-application/web.yaml

@@ -13,7 +13,7 @@ spec:
   selector:
     app: nginx
 ---
-apiVersion: apps/v1beta2 # for versions before 1.8.0 use apps/v1beta1
+apiVersion: apps/v1
 kind: StatefulSet
 metadata:
   name: web

docs/tutorials/stateful-application/webp.yaml

@@ -13,7 +13,7 @@ spec:
   selector:
     app: nginx
 ---
-apiVersion: apps/v1beta2 # for versions before 1.8.0 use apps/v1beta1
+apiVersion: apps/v1
 kind: StatefulSet
 metadata:
   name: web

docs/tutorials/stateful-application/zookeeper.yaml

@@ -38,7 +38,7 @@ spec:
       app: zk
   maxUnavailable: 1
 ---
-apiVersion: apps/v1beta2 # for versions before 1.8.0 use apps/v1beta1
+apiVersion: apps/v1
 kind: StatefulSet
 metadata:
   name: zk