Using an SFS File System Through a Dynamic PV

Prerequisites

• You have created a cluster and installed the CCE Container Storage (Everest) add-on in the cluster.
• To create a cluster using commands, ensure kubectl is used. For details, see Accessing a Cluster Using kubectl.

Automatically Creating an SFS File System Through kubectl

1. Use kubectl to access the cluster.
2. Use StorageClass to dynamically create a PVC and PV.
   1. Create the pvc-sfs-auto.yaml file.

      apiVersion: v1
      kind: PersistentVolumeClaim
      metadata:
        name: pvc-sfs-auto
        namespace: default
        annotations: 
      
      
      
          everest.io/csi.volume-name-prefix: test  # (Optional) Storage volume name prefix of the automatically created underlying storage
      spec:
        accessModes:
          - ReadWriteMany             # The value must be ReadWriteMany for SFS.
        resources:
          requests:
            storage: 1Gi             # SFS volume capacity
        storageClassName: csi-nas    # The StorageClass is SFS.
      
      

      Table 1 Key parameters

      Parameter	Mandatory	Description
      storage	Yes	Requested capacity in the PVC, in Gi. For SFS, this parameter is used only for verification and cannot be empty or 0. Its value is fixed at 1, and any value set will not take effect for SFS file systems.
      everest.io/csi.volume-name-prefix	No	(Optional) This parameter is available only when the cluster version is v1.23.14-r0, v1.25.9-r0, v1.27.6-r0, v1.28.4-r0, or later, and Everest of v2.4.15 or later is installed in the cluster. This parameter specifies the name of the underlying storage that is automatically created. The actual underlying storage name is in the format of "Storage volume name prefix + PVC UID". If this parameter is left blank, the default prefix pvc will be used. Enter 1 to 26 characters that cannot start or end with a hyphen (-). Only lowercase letters, digits, and hyphens (-) are allowed. For example, if the storage volume name prefix is set to test, the actual underlying storage name is test-{UID}.

   2. Run the following command to create a PVC:

      kubectl apply -f pvc-sfs-auto.yaml
      
      

3. Create an application.
   1. Create a file named web-demo.yaml. In this example, the SFS volume is mounted to the /data path.

      apiVersion: apps/v1
      kind: Deployment
      metadata:
        name: web-demo
        namespace: default
      spec:
        replicas: 2
        selector:
          matchLabels:
            app: web-demo
        template:
          metadata:
            labels:
              app: web-demo
          spec:
            containers:
            - name: container-1
              image: nginx:latest
              volumeMounts:
              - name: pvc-sfs-volume    # Volume name, which must be the same as the volume name in the volumes field
                mountPath: /data  # Location where the storage volume is mounted
            imagePullSecrets:
              - name: default-secret
            volumes:
              - name: pvc-sfs-volume    # Volume name, which can be customized
                persistentVolumeClaim:
                  claimName: pvc-sfs-auto    # Name of the created PVC
      
      

   2. Run the following command to create a workload to which the SFS volume is mounted:

      kubectl apply -f web-demo.yaml
      
      

      After the workload is created, the data in the container mount directory will be persistently stored. Verify the storage by referring to Verifying Data Persistence and Sharing.

Verifying Data Persistence and Sharing

1. View the deployed application and files.
   1. Run the following command to view the created pod:

      kubectl get pod | grep web-demo
      
      

      Expected output:

      web-demo-846b489584-mjhm9   1/1     Running   0             46s
      web-demo-846b489584-wvv5s   1/1     Running   0             46s
      
      

   2. Run the following commands in sequence to view the files in the /data path of the pods:

      kubectl exec web-demo-846b489584-mjhm9 -- ls /data
      kubectl exec web-demo-846b489584-wvv5s -- ls /data
      
      

      If no result is returned for both pods, no file exists in the /data path.

2. Run the following command to create a file named static in the /data path:

   kubectl exec web-demo-846b489584-mjhm9 --  touch /data/static
   
   

3. Run the following command to check the files in the /data path:

   kubectl exec web-demo-846b489584-mjhm9 -- ls /data
   
   

   Expected output:

   static
   
   

4. Verify data persistence.
   1. Run the following command to delete the pod named web-demo-846b489584-mjhm9:

      kubectl delete pod web-demo-846b489584-mjhm9
      
      

      Expected output:

      pod "web-demo-846b489584-mjhm9" deleted
      
      

      After the deletion, the Deployment controller automatically creates a replica.

   2. Run the following command to view the created pod:

      kubectl get pod | grep web-demo
      
      

      The expected output is as follows, in which web-demo-846b489584-d4d4j is the newly created pod:

      web-demo-846b489584-d4d4j   1/1     Running   0             110s
      web-demo-846b489584-wvv5s    1/1     Running   0             7m50s
      
      

   3. Run the following command to check whether the files in the /data path of the new pod have been modified:

      kubectl exec web-demo-846b489584-d4d4j -- ls /data
      
      

      Expected output:

      static
      
      

      The static file is retained, indicating that the data in the file system can be stored persistently.

5. Verify data sharing.
   1. Run the following command to view the created pod:

      kubectl get pod | grep web-demo
      
      

      Expected output:

      web-demo-846b489584-d4d4j   1/1     Running   0             7m
      web-demo-846b489584-wvv5s   1/1     Running   0             13m
      
      

   2. Run the following command to create a file named share in the /data path of either pod: In this example, select the pod named web-demo-846b489584-d4d4j.

      kubectl exec web-demo-846b489584-d4d4j --  touch /data/share
      
      

      Check the files in the /data path of the pod.

      kubectl exec web-demo-846b489584-d4d4j -- ls /data
      
      

      Expected output:

      share
      static
      
      

   3. Check whether the share file exists in the /data path of another pod (web-demo-846b489584-wvv5s) as well to verify data sharing.

      kubectl exec web-demo-846b489584-wvv5s -- ls /data
      
      

      Expected output:

      share
      static
      
      

      After you create a file in the /data path of a pod, if the file is also created in the /data path of the other pod, the two pods share the same volume.

Related Operations

You can also perform the operations listed in Table 2.