Container Service for Kubernetes:Use a StatefulSet to create a stateful application

Create from the console

1. Log on to the ACK console. In the left navigation pane, click Clusters.

2. On the Clusters page, click the cluster name. In the left-side pane, choose Workloads > StatefulSets.

3. In the upper-left corner of the StatefulSets page, click Create from Image.

4. In the Basic Information step, configure the basic settings of the application. Click Next.

5. In the Container step, configure Image Name and Port. Keep other parameters at their default values. For Image Name, use:

   Important

   The cluster must have Internet access to pull this image. If you kept the default value for Configure SNAT for VPC when creating the cluster, Internet access is already enabled. For existing clusters, see Enable an existing ACK cluster to access the Internet.

   registry.cn-hangzhou.aliyuncs.com/acs-sample/nginx:latest

   Click Next.

   

6. In the Advanced step, go to the Access Control section. Create a Cluster IP Service, select Headless Service, and click OK. Then click Create.

   

The parameters in the Basic Information, Container, and Advanced steps are the same as for a Deployment. For details on all parameters, see Parameters.

Create with kubectl

1. Create a file named statefulset.yaml and paste the following content. The manifest defines three resources:

   • A headless Service named nginx, providing stable DNS names for pods

   • A StatefulSet named nginx-test with a hostPath volume mounted

   • A LoadBalancer Service named nginx-test-svc, used to verify access to the StatefulSet

   apiVersion: v1
   kind: Service
   metadata:
     name: nginx
     labels:
       app: nginx
   spec:
     clusterIP: None  # Headless Service
     selector:
       app: nginx
     ports:
     - port: 80
       name: http
   ---
   apiVersion: apps/v1
   kind: StatefulSet   # The workload type.
   metadata:
     name: nginx-test
     namespace: default  # Change the namespace as needed.
     labels:
       app: nginx
   spec:
     serviceName: "nginx" # Specify the name of the headless Service you created.
     replicas: 2  # Specify the number of pods.
     selector:
       matchLabels:
         app: nginx
     template: # The pod configurations.
       metadata:
         labels: # The pod labels.
           app: nginx
       spec:
         containers:
         - name: nginx  # The name of the container.
           image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6  # The version of the NGINX image.
           ports:
           - containerPort: 80  # The port exposed by the container.
             protocol: TCP  # Set the protocol to TCP or UDP.
           volumeMounts:
           - name: node-dir-volume  # The volume name. The value must be the same as the volume name specified in the following volumes section.
             mountPath: /tmp  # The mount path of the volume in the container.
         volumes:
         - name: node-dir-volume
           hostPath:
             path: /local_storage  # The directory on the host that you want to mount as a volume.
             type: DirectoryOrCreate     # If the specified directory does not exist, the system automatically creates the directory.
   ---
   apiVersion: v1
   kind: Service
   metadata:
     name: nginx-test-svc
     namespace: default  # Change the namespace as needed.
     labels:
       app: nginx
   spec:
     selector:
       app: nginx  # The label used to match backend pods.
     ports:
       - port: 80           # The port provided by the Service in the cluster.
         targetPort: 80     # The port on which the application in the container listens (containerPort).
         protocol: TCP      # The protocol. Default value: TCP.
     type: LoadBalancer      # The Service type. Default value: ClusterIP. ClusterIP Services are accessible from within the cluster.

2. Apply the manifest:

   kubectl apply -f statefulset.yaml

   Expected output:

   service/nginx created
   statefulset.apps/nginx-test created
   service/nginx-test-svc created

3. Get the public IP address of the LoadBalancer Service:

   kubectl get svc

   Expected output:

   NAME            TYPE           CLUSTER-IP       EXTERNAL-IP     PORT(S)        AGE
   kubernetes      ClusterIP      172.16.**.***    <none>          443/TCP        4h47m
   nginx           ClusterIP      None             <none>          80/TCP         1h10m
   nginx-test-svc  LoadBalancer   172.16.**.***    106.14.**.***   80:31130/TCP   1h10m

4. Open a browser and go to the external IP address (106.14..*) to confirm the NGINX container is accessible.