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 Connecting to a Cluster Using kubectl.
• You have created an SFS file system that is in the same VPC as the cluster.
• Before using SFS 3.0 for storage, ensure a VPC endpoint has been created in the VPC where the cluster is located for the cluster to access the SFS 3.0 file system. For details, see Configure a VPC Endpoint.

Notes and Constraints

• If SFS 3.0 is used, the CCE Container Storage (Everest) add-on of v2.0.9 or later must be installed in the cluster.
• If SFS 3.0 is used, the owner group and permission of the mount point cannot be modified. The default owner of the mount point is user root.
• If SFS 3.0 is used, there may be a latency during the creation or deletion of PVCs and PVs. The billing duration is determined by the time when the SFS system is created or deleted on the SFS console.
• If the reclamation policy of SFS 3.0 is set to Delete, PVs and PVCs can be properly deleted only after all files are manually deleted from the mounted SFS system.

Automatically Creating an SFS File System on the Console

1. Log in to the CCE console and click the cluster name to access the cluster console.
2. Dynamically create a PVC and PV.
   1. Choose Storage in the navigation pane. In the right pane, click the PVCs tab. Click Create PVC in the upper right corner. In the dialog box displayed, configure PVC parameters.

      Parameter	Description
      PVC Type	In this example, select SFS.
      PVC Name	Enter the PVC name, which must be unique in a namespace.
      Creation Method	If no underlying storage is available, select Dynamically provision to create a PVC, PV, and underlying storage on the console in cascading mode. If underlying storage is available, create a PV or use an existing PV to statically create a PVC. For details, see Using an Existing SFS File System Through a Static PV. In this document, Dynamically provision is selected.
      Storage Classes	The storage class for SFS volumes is csi-sfs or csi-nas.
      (Optional) Storage Volume Name Prefix	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. For example, if the storage volume name prefix is set to test, the actual underlying storage name is test-{UID}.
      Access Mode	SFS volumes support only ReadWriteMany, indicating that a storage volume can be mounted to multiple nodes in read/write mode. For details, see Volume Access Modes.
      Encryption	Configure whether to encrypt underlying storage if the storage class is csi-nas. If you select Enabled (key), an encryption key must be configured.

   2. Click Create to create a PVC and a PV.

      You can choose Storage in the navigation pane and view the created PVC and PV on the PVCs and PVs tab pages, respectively.

3. Create an application.
   1. Choose Workloads in the navigation pane. In the right pane, click the Deployments tab.
   2. Click Create Workload in the upper right corner. On the displayed page, click Data Storage in the Container Settings area and click Add Volume to select PVC.
      Mount and use storage volumes, as shown in Table 1. For details about other parameters, see Workloads.

      Table 1 Mounting a storage volume

      Parameter	Description
      PVC	Select an existing SFS volume.
      Mount Path	Enter a mount path, for example, /tmp. This parameter specifies a container path to which a data volume will be mounted. Do not mount the volume to a system directory such as / or /var/run. This may lead to container errors. Mount the volume to an empty directory. If the directory is not empty, ensure that there are no files that affect container startup. Otherwise, the files will be replaced, leading to container startup failures or workload creation failures. NOTICE: If a volume is mounted to a high-risk directory, use an account with minimum permissions to start the container. Otherwise, high-risk files on the host may be damaged.
      Subpath	Enter the subpath of the storage volume and mount a path in the storage volume to the container. In this way, different folders of the same storage volume can be used in a single pod. tmp, for example, indicates that data in the mount path of the container is stored in the tmp folder of the storage volume. If this parameter is left blank, the root path will be used by default.
      Permission	Read-only: You can only read the data in the mounted volumes. Read-write: You can modify the data volumes mounted to the path. Newly written data will not be migrated if the container is migrated, which may cause data loss.

      In this example, the disk is mounted to the /data path of the container. The container data generated in this path is stored in the SFS file system.

      

   3. After the configuration, click Create Workload.

      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.

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/crypt-key-id: <your_key_id>      # (Optional) ID of the key for encrypting file systems
      
          everest.io/crypt-alias: sfs/default         # (Optional) Key name. Mandatory for encrypting volumes.
      
          everest.io/crypt-domain-id: <your_domain_id>   # (Optional) ID of the tenant to which an encrypted volume belongs. Mandatory for encrypting volumes.
      
          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    # StorageClass is SFS. csi-nas indicates that SFS Capacity-Oriented is used, and csi-sfs indicates that SFS 3.0 is used.

      Table 2 Key parameters

      Parameter	Mandatory	Description
      storage	Yes	Requested capacity in the PVC, in Gi. For SFS, this field is used only for verification (cannot be empty or 0). Its value is fixed at 1, and any value you set does not take effect for SFS file systems.
      storageClassName	Yes	Name of a storage class. csi-sfs (recommended): indicates that SFS 3.0 is used. csi-nas: indicates that an SFS 1.0 Capacity-Oriented file system is used.
      everest.io/crypt-key-id	No	If StorageClass is csi-nas, you can determine whether to encrypt the underlying storage. This parameter is mandatory when an SFS system is encrypted. Enter the encryption key ID selected during SFS system creation. You can use a custom key or the default key named sfs/default. To obtain a key ID, log in to the DEW console, locate the key to be encrypted, and copy the key ID.
      everest.io/crypt-alias	No	Key name, which is mandatory when you create an encrypted volume. To obtain a key name, log in to the DEW console, locate the key to be encrypted, and copy the key name.
      everest.io/crypt-domain-id	No	ID of the tenant to which the encrypted volume belongs. This parameter is mandatory for creating an encrypted volume. To obtain a tenant ID, hover the cursor over the username in the upper right corner of the ECS console, choose My Credentials, and copy the account ID.
      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

Troubleshooting

Mounting the SFS 3.0 storage timed out, and the error message is as follows:

MountVolume.SetUp failed for volume "***" : rpc error: code = Internal desc = [30834707-b8fc-11ee-ba7a-fa163eaacb17] failed to execute cmd: "systemd-run --scope  mount -t nfs -o proto=tcp -o vers=3 -o timeo=600 -o noresvport -o nolock ***.sfs3.cn-east-3.myhuaweicloud.com:/*** /mnt/paas/kubernetes/kubelet/pods/add9a323-10e2-434f-b151-42675f83860e/volumes/kubernetes.io~csi/***/mount". outputs: Running scope as unit run-1597979.scope.; error: signal: killed. please check whether the volumeAttributes of related PersistentVolume of the volume is correct and whether it can be mounted.

Solution

Before using SFS 3.0, create a VPC endpoint. Otherwise, the cluster cannot access the SFS 3.0 file system. As a result, the mounting times out and fails. For details, see Configuring a VPC Endpoint.