Help Center/ Cloud Container Engine/ User Guide/ Storage/ Scalable File Service/ Using an Existing SFS File System Through a Static PV
Updated on 2024-11-11 GMT+08:00
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Using an Existing SFS File System Through a Static PV

SFS is a network-attached storage (NAS) that provides shared, scalable, and high-performance file storage. It applies to large-capacity expansion and cost-sensitive services. This section describes how to use an existing SFS file system to statically create PVs and PVCs for data persistence and sharing in workloads.

Prerequisites

Notes and Constraints

  • Multiple PVs can use the same SFS or SFS Turbo file system with the following restrictions:
    • Do not mount the PVCs/PVs that use the same underlying SFS or SFS Turbo volume to one pod. This will lead to a pod startup failure because not all PVCs can be mounted to the pod due to the same volumeHandle value.
    • The persistentVolumeReclaimPolicy parameter in the PVs must be set to Retain. Otherwise, when a PV is deleted, the associated underlying volume may be deleted. In this case, other PVs associated with the underlying volume malfunction.
    • When the underlying volume is repeatedly used, enable isolation and protection for ReadWriteMany at the application layer to prevent data overwriting and loss.

Using an Existing SFS File System on the Console

  1. Log in to the CCE console and click the cluster name to access the cluster console.
  2. Statically 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 underlying storage is available, create a PV or use an existing PV to statically create a PVC.
      • If no underlying storage is available, select Dynamically provision. For details, see Using an SFS File System Through a Dynamic PV.

      In this example, select Create new to create both a PV and PVC on the console.

      PVa

      Select an existing PV in the cluster. For details about how to create a PV, see "Creating a storage volume" in Related Operations.

      You do not need to specify this parameter in this example.

      SFSb

      Click Select SFS. On the displayed page, select the SFS file system that meets your requirements and click OK.

      PV Nameb

      Enter the PV name, which must be unique in the same cluster.

      Access Modeb

      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.

      Reclaim Policyb

      You can select Delete or Retain to specify the reclaim policy of the underlying storage when the PVC is deleted. For details, see PV Reclaim Policy.

      NOTE:

      If multiple PVs use the same underlying storage volume, use Retain to prevent the underlying volume from being deleted with a PV.

      Mount Optionsb

      Enter the mounting parameter key-value pairs. For details, see Configuring SFS Volume Mount Options.

      a: The parameter is available when Creation Method is set to Use existing.

      b: The parameter is available when Creation Method is set to Create new.

    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.

  1. Use kubectl to access the cluster.
  2. Create a PV.

    1. Create the pv-sfs.yaml file.
      Example: 
      apiVersion: v1
kind: PersistentVolume
metadata:
  annotations:
    pv.kubernetes.io/provisioned-by: everest-csi-provisioner
    everest.io/reclaim-policy: retain-volume-only      # (Optional) The underlying volume is retained when the PV is deleted.
  name: pv-sfs    # PV name
spec:
  accessModes:
  - ReadWriteMany      # Access mode. The value must be ReadWriteMany for SFS.
  capacity:
    storage: 1Gi     # SFS volume capacity
  csi:
    driver: nas.csi.everest.io    # Dependent storage driver for the mounting
    fsType: nfs
    volumeHandle: <your_volume_id>   # SFS Capacity-Oriented volume ID
    volumeAttributes:
      everest.io/share-export-location: <your_location>  # Shared path of the SFS volume
      storage.kubernetes.io/csiProvisionerIdentity: everest-csi-provisioner
  persistentVolumeReclaimPolicy: Retain    # Reclaim policy
  storageClassName: csi-nas               # StorageClass name. csi-nas indicates that SFS Capacity-Oriented is used.
  mountOptions: []                         # Mount options
      Table 2 Key parameters

      Parameter

      Mandatory

      Description

      everest.io/reclaim-policy

      No

      Only retain-volume-only is supported.

      This parameter is valid only when the Everest version is 1.2.9 or later and the reclaim policy is Delete. If the reclaim policy is Delete and the current value is retain-volume-only, the associated PV is deleted while the underlying storage volume is retained, when a PVC is deleted.

      volumeHandle

      Yes

      Volume ID if SFS Capacity-Oriented is used.

      Log in to the CCE console, choose Service List > Storage > Scalable File Service, and select SFS Capacity-Oriented. In the list, click the name of the target SFS file system. On the details page, copy the content following ID.

      everest.io/share-export-location

      Yes

      Shared path of the file system.

      On the management console, choose Service List > Storage > Scalable File Service. You can obtain the shared path of the file system from the Mount Address column.

      mountOptions

      Yes

      Mount options.

      If not specified, the following configurations are used by default. For details, see Configuring SFS Volume Mount Options.

      mountOptions:
- vers=3
- timeo=600
- nolock
- hard

      persistentVolumeReclaimPolicy

      Yes

      A reclaim policy is supported when the cluster version is or later than 1.19.10 and the Everest version is or later than 1.2.9.

      The Delete and Retain reclaim policies are supported. For details, see PV Reclaim Policy. If multiple PVs use the same SFS volume, use Retain to prevent the underlying volume from being deleted with a PV.

      Retain: When a PVC is deleted, both the PV and underlying storage resources will be retained. You need to manually delete these resources. After the PVC is deleted, the PV is in the Released state and cannot be bound to a PVC again.

      Delete: When a PVC is deleted, its PV will also be deleted.

      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

      StorageClass name csi-nas, indicating that SFS 1.0 Capacity-Oriented is used for storage.
    2. Run the following command to create a PV: 
      kubectl apply -f pv-sfs.yaml

  3. Create a PVC.

    1. Create the pvc-sfs.yaml file. 
      apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-sfs
  namespace: default
  annotations:
    volume.beta.kubernetes.io/storage-provisioner: everest-csi-provisioner
spec:
  accessModes:
  - ReadWriteMany               # The value must be ReadWriteMany for SFS.
  resources:
    requests:
      storage: 1Gi               # SFS volume capacity
  storageClassName: csi-nas     # StorageClass name, which must be the same as that of the PV
  volumeName: pv-sfs    # PV name
      Table 3 Key parameters

      Parameter

      Mandatory

      Description

      storage

      Yes

      Requested capacity in the PVC, in Gi.

      The value must be the same as the storage size of the existing PV.

      storageClassName

      Yes

      StorageClass name csi-nas, which must be the same as the StorageClass of the PV specified in 1. This indicates that SFS 1.0 Capacity-Oriented is used for storage.

      volumeName

      Yes

      PV name, which must be the same as the PV name in 1.
    2. Run the following command to create a PVC: 
      kubectl apply -f pvc-sfs.yaml

  4. 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    # 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 4.
Table 4 Related operations

Operation

Description

Procedure

Creating a storage volume (PV)

Create a PV on the CCE console.
  1. Choose Storage in the navigation pane. In the right pane, click the PVs tab. Click Create PersistentVolume in the upper right corner. In the dialog box displayed, configure parameters.
    • Volume Type: Select SFS.
    • SFS: Click Select SFS. On the displayed page, select the SFS file system that meets your requirements and click OK.
    • PV Name: Enter the PV name, which must be unique in a cluster.
    • 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.
    • Reclaim Policy: Delete or Retain is supported. For details, see PV Reclaim Policy.
      NOTE:

      If multiple PVs use the same underlying storage volume, use Retain to prevent the underlying volume from being deleted with a PV.

    • Mount Options: Enter the mounting parameter key-value pairs. For details, see Configuring SFS Volume Mount Options.
  2. Click Create.

Viewing events

View event names, event types, number of occurrences, Kubernetes events, first occurrence time, and last occurrence time of the PVC or PV.
  1. Choose Storage in the navigation pane. In the right pane, click the PVCs or PVs tab.
  2. Click View Events in the Operation column of the target PVC or PV to view events generated within one hour (events are retained for one hour).

Viewing a YAML file

View, copy, or download the YAML file of a PVC or PV.
  1. Choose Storage in the navigation pane. In the right pane, click the PVCs or PVs tab.
  2. Click View YAML in the Operation column of the target PVC or PV to view or download the YAML.
Parent Topic: Scalable File Service