Creating an SFS Subdirectory Using a Dynamic PV

Prerequisites

• You have created a cluster and installed the CCE Container Storage (Everest) add-on of v2.4.41 or later in the cluster.
• To create a cluster using commands, ensure kubectl is used. For details, see Accessing a Cluster Using kubectl.
• You have created an available SFS file system, and the SFS file system and the cluster are in the same VPC. Before using a general purpose file system (SFS 3.0 Capacity-Oriented) for storage, ensure a VPC endpoint has been created in the VPC where the cluster is located for the cluster to access the file system. For details, see Creating a VPC Endpoint.

Dynamically Creating an SFS Subdirectory

CCE allows you to create SFS subdirectory PVCs via the console or kubectl based on the configured StorageClasses. After PVC creation, CCE dynamically allocates storage resources and mounts the PVCs to the specified workloads. To do so, perform the following operations.

Verifying Subpath Mounting and Read/Write Operations

After a PVC is created, mount the bound PV to an application. This section describes how to create two Deployments that reference the same PVC, enabling multiple pods to share the same NAS subpath.

1. Create a workload YAML file.

   Create deployment-sfs-demo.yaml with the following content:

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: sfs-demo
     namespace: default
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: sfs-demo
     template:
       metadata:
         labels:
           app: sfs-demo
       spec:
         containers:
         - name: container-0
           image: nginx:latest
           imagePullPolicy: IfNotPresent
           volumeMounts:
           - name: sfs-storage
             mountPath: /usr/share/nginx/html/data   # Mount path in a container
         volumes:
         - name: sfs-storage
           persistentVolumeClaim:
             claimName: pvc-sfs-subpath   # Reference the PVC created in the previous step.
         imagePullSecrets:
         - name: default-secret

2. Create workloads.

   kubectl apply -f deployment-sfs-demo.yaml

3. Verify that the subpath is mounted correctly.

   # Obtain the pod name.
   POD_NAME=$(kubectl get pods -l app=sfs-demo -o jsonpath='{.items[0].metadata.name}')
   
   # Access the container and check the mount point.
   kubectl exec -it $POD_NAME -- /bin/sh -c "ls -ld /usr/share/nginx/html/data"

   Expected output:

   drwxr-xr-x 2 root root 0 ... /usr/share/nginx/html/data

   The directory exists and the permissions are correct.

4. Test file read/write operations.

   # Write test files in the container.
   kubectl exec -it $POD_NAME -- /bin/sh -c "echo 'Hello SFS Subpath - End to End Test' > /usr/share/nginx/html/data/test.txt"
   
   # Read the test file to verify that the write operation is successful.
   kubectl exec -it $POD_NAME -- /bin/sh -c "cat /usr/share/nginx/html/data/test.txt"

   Expected output:

   Hello SFS Subpath - End to End Test

   If the file can be written and read successfully, the storage volume's read/write functions are working correctly.

Helpful Links

If a storage volume fails to mount to a workload, rectify the fault by referring to What Should I Do If a Storage Volume Cannot Be Mounted or the Mounting Times Out?