Merge pull request #39541 from Zhuzhenghao/scale-stateful-set

k8s-ci-robot · web-flow · commit 2483764fae00 · 2023-02-19T23:31:38.000-08:00
Add code blocks in page run-single-instance-stateful-application
diff --git a/content/en/docs/tasks/run-application/run-single-instance-stateful-application.md b/content/en/docs/tasks/run-application/run-single-instance-stateful-application.md
@@ -10,36 +10,25 @@ This page shows you how to run a single-instance stateful application
 in Kubernetes using a PersistentVolume and a Deployment. The
 application is MySQL.
 
-
-
-
 ## {{% heading "objectives" %}}
 
-
-* Create a PersistentVolume referencing a disk in your environment.
-* Create a MySQL Deployment.
-* Expose MySQL to other pods in the cluster at a known DNS name.
-
-
-
+- Create a PersistentVolume referencing a disk in your environment.
+- Create a MySQL Deployment.
+- Expose MySQL to other pods in the cluster at a known DNS name.
 
 ## {{% heading "prerequisites" %}}
 
+- {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
 
-* {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
-
-* {{< include "default-storage-class-prereqs.md" >}}
-
-
-
+- {{< include "default-storage-class-prereqs.md" >}}
 
 <!-- lessoncontent -->
 
 ## Deploy MySQL
 
 You can run a stateful application by creating a Kubernetes Deployment
 and connecting it to an existing PersistentVolume using a
-PersistentVolumeClaim.  For example, this YAML file describes a
+PersistentVolumeClaim. For example, this YAML file describes a
 Deployment that runs MySQL and references the PersistentVolumeClaim. The file
 defines a volume mount for /var/lib/mysql, and then creates a
 PersistentVolumeClaim that looks for a 20G volume. This claim is
@@ -55,80 +44,96 @@ for a secure solution.
 
 1. Deploy the PV and PVC of the YAML file:
 
-        kubectl apply -f https://k8s.io/examples/application/mysql/mysql-pv.yaml
+   ```shell
+   kubectl apply -f https://k8s.io/examples/application/mysql/mysql-pv.yaml
+   ```
 
 1. Deploy the contents of the YAML file:
 
-        kubectl apply -f https://k8s.io/examples/application/mysql/mysql-deployment.yaml
+   ```shell
+   kubectl apply -f https://k8s.io/examples/application/mysql/mysql-deployment.yaml
+   ```
 
 1. Display information about the Deployment:
 
-        kubectl describe deployment mysql
-
-    The output is similar to this:
-
-        Name:                 mysql
-        Namespace:            default
-        CreationTimestamp:    Tue, 01 Nov 2016 11:18:45 -0700
-        Labels:               app=mysql
-        Annotations:          deployment.kubernetes.io/revision=1
-        Selector:             app=mysql
-        Replicas:             1 desired | 1 updated | 1 total | 0 available | 1 unavailable
-        StrategyType:         Recreate
-        MinReadySeconds:      0
-        Pod Template:
-          Labels:       app=mysql
-          Containers:
-           mysql:
-            Image:      mysql:5.6
-            Port:       3306/TCP
-            Environment:
-              MYSQL_ROOT_PASSWORD:      password
-            Mounts:
-              /var/lib/mysql from mysql-persistent-storage (rw)
-          Volumes:
-           mysql-persistent-storage:
-            Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
-            ClaimName:  mysql-pv-claim
-            ReadOnly:   false
-        Conditions:
-          Type          Status  Reason
-          ----          ------  ------
-          Available     False   MinimumReplicasUnavailable
-          Progressing   True    ReplicaSetUpdated
-        OldReplicaSets:       <none>
-        NewReplicaSet:        mysql-63082529 (1/1 replicas created)
-        Events:
-          FirstSeen    LastSeen    Count    From                SubobjectPath    Type        Reason            Message
-          ---------    --------    -----    ----                -------------    --------    ------            -------
-          33s          33s         1        {deployment-controller }             Normal      ScalingReplicaSet Scaled up replica set mysql-63082529 to 1
+   ```shell
+   kubectl describe deployment mysql
+   ```
+
+   The output is similar to this:
+
+   ```
+   Name:                 mysql
+   Namespace:            default
+   CreationTimestamp:    Tue, 01 Nov 2016 11:18:45 -0700
+   Labels:               app=mysql
+   Annotations:          deployment.kubernetes.io/revision=1
+   Selector:             app=mysql
+   Replicas:             1 desired | 1 updated | 1 total | 0 available | 1 unavailable
+   StrategyType:         Recreate
+   MinReadySeconds:      0
+   Pod Template:
+     Labels:       app=mysql
+     Containers:
+       mysql:
+       Image:      mysql:5.6
+       Port:       3306/TCP
+       Environment:
+         MYSQL_ROOT_PASSWORD:      password
+       Mounts:
+         /var/lib/mysql from mysql-persistent-storage (rw)
+     Volumes:
+       mysql-persistent-storage:
+       Type:       PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
+       ClaimName:  mysql-pv-claim
+       ReadOnly:   false
+   Conditions:
+     Type          Status  Reason
+     ----          ------  ------
+     Available     False   MinimumReplicasUnavailable
+     Progressing   True    ReplicaSetUpdated
+   OldReplicaSets:       <none>
+   NewReplicaSet:        mysql-63082529 (1/1 replicas created)
+   Events:
+     FirstSeen    LastSeen    Count    From                SubobjectPath    Type        Reason            Message
+     ---------    --------    -----    ----                -------------    --------    ------            -------
+     33s          33s         1        {deployment-controller }             Normal      ScalingReplicaSet Scaled up replica set mysql-63082529 to 1
+   ```
 
 1. List the pods created by the Deployment:
 
-        kubectl get pods -l app=mysql
+   ```shell
+   kubectl get pods -l app=mysql
+   ```
 
-    The output is similar to this:
+   The output is similar to this:
 
-        NAME                   READY     STATUS    RESTARTS   AGE
-        mysql-63082529-2z3ki   1/1       Running   0          3m
+   ```
+   NAME                   READY     STATUS    RESTARTS   AGE
+   mysql-63082529-2z3ki   1/1       Running   0          3m
+   ```
 
 1. Inspect the PersistentVolumeClaim:
 
-        kubectl describe pvc mysql-pv-claim
-
-    The output is similar to this:
-
-        Name:         mysql-pv-claim
-        Namespace:    default
-        StorageClass:
-        Status:       Bound
-        Volume:       mysql-pv-volume
-        Labels:       <none>
-        Annotations:    pv.kubernetes.io/bind-completed=yes
-                        pv.kubernetes.io/bound-by-controller=yes
-        Capacity:     20Gi
-        Access Modes: RWO
-        Events:       <none>
+   ```shell
+   kubectl describe pvc mysql-pv-claim
+   ```
+
+   The output is similar to this:
+
+   ```
+   Name:         mysql-pv-claim
+   Namespace:    default
+   StorageClass:
+   Status:       Bound
+   Volume:       mysql-pv-volume
+   Labels:       <none>
+   Annotations:    pv.kubernetes.io/bind-completed=yes
+                   pv.kubernetes.io/bound-by-controller=yes
+   Capacity:     20Gi
+   Access Modes: RWO
+   Events:       <none>
+   ```
 
 ## Accessing the MySQL instance
 
@@ -140,7 +145,7 @@ behind a Service and you don't intend to increase the number of Pods.
 
 Run a MySQL client to connect to the server:
 
-```
+```shell
 kubectl run -it --rm --image=mysql:5.6 --restart=Never mysql-client -- mysql -h mysql -ppassword
 ```
 
@@ -161,11 +166,11 @@ The image or any other part of the Deployment can be updated as usual
 with the `kubectl apply` command. Here are some precautions that are
 specific to stateful apps:
 
-* Don't scale the app. This setup is for single-instance apps
+- Don't scale the app. This setup is for single-instance apps
   only. The underlying PersistentVolume can only be mounted to one
   Pod. For clustered stateful apps, see the
   [StatefulSet documentation](/docs/concepts/workloads/controllers/statefulset/).
-* Use `strategy:` `type: Recreate` in the Deployment configuration
+- Use `strategy:` `type: Recreate` in the Deployment configuration
   YAML file. This instructs Kubernetes to _not_ use rolling
   updates. Rolling updates will not work, as you cannot have more than
   one Pod running at a time. The `Recreate` strategy will stop the
@@ -175,7 +180,7 @@ specific to stateful apps:
 
 Delete the deployed objects by name:
 
-```
+```shell
 kubectl delete deployment,svc mysql
 kubectl delete pvc mysql-pv-claim
 kubectl delete pv mysql-pv-volume
@@ -188,20 +193,12 @@ PersistentVolume when it sees that you deleted the PersistentVolumeClaim.
 Some dynamic provisioners (such as those for EBS and PD) also release the
 underlying resource upon deleting the PersistentVolume.
 
-
-
-
 ## {{% heading "whatsnext" %}}
 
+- Learn more about [Deployment objects](/docs/concepts/workloads/controllers/deployment/).
 
-* Learn more about [Deployment objects](/docs/concepts/workloads/controllers/deployment/).
-
-* Learn more about [Deploying applications](/docs/tasks/run-application/run-stateless-application-deployment/)
-
-* [kubectl run documentation](/docs/reference/generated/kubectl/kubectl-commands/#run)
-
-* [Volumes](/docs/concepts/storage/volumes/) and [Persistent Volumes](/docs/concepts/storage/persistent-volumes/)
-
-
+- Learn more about [Deploying applications](/docs/tasks/run-application/run-stateless-application-deployment/)
 
+- [kubectl run documentation](/docs/reference/generated/kubectl/kubectl-commands/#run)
 
+- [Volumes](/docs/concepts/storage/volumes/) and [Persistent Volumes](/docs/concepts/storage/persistent-volumes/)
