Help Center> Cloud Container Engine> Best Practices> Storage> How Do I Change the Storage Class Used by a Cluster of v1.15 from FlexVolume to CSI Everest?
Updated on 2023-05-23 GMT+08:00

How Do I Change the Storage Class Used by a Cluster of v1.15 from FlexVolume to CSI Everest?

In clusters later than v1.15.11-r1, CSI (the everest add-on) has taken over all functions of fuxi FlexVolume (the storage-driver add-on) for managing container storage. You are advised to use CSI Everest.

To migrate your storage volumes, create a static PV to associate with the original underlying storage, and then create a PVC to associate with this static PV. When you upgrade your application, mount the new PVC to the original mounting path to migrate the storage volumes.

Services will be interrupted during the migration. Therefore, properly plan the migration and back up data.

Procedure

  1. (Optional) Back up data to prevent data loss in case of exceptions.
  2. Configure a YAML file of the PV in the CSI format according to the PV in the FlexVolume format and associate the PV with the existing storage.

    To be specific, run the following commands to configure the pv-example.yaml file, which is used to create a PV.

    touch pv-example.yaml

    vi pv-example.yaml

    Configuration example of a PV for an EVS volume:
    apiVersion: v1
    kind: PersistentVolume
    metadata:
      labels:
        failure-domain.beta.kubernetes.io/region: ap-southeast-1
        failure-domain.beta.kubernetes.io/zone: <zone name>
      annotations:
        pv.kubernetes.io/provisioned-by: everest-csi-provisioner
      name: pv-evs-example
    spec:
      accessModes:
      - ReadWriteOnce
      capacity:
        storage: 10Gi
      csi:
        driver: disk.csi.everest.io
        fsType: ext4
        volumeAttributes:
          everest.io/disk-mode: SCSI
          everest.io/disk-volume-type: SAS
          storage.kubernetes.io/csiProvisionerIdentity: everest-csi-provisioner
        volumeHandle: 0992dbda-6340-470e-a74e-4f0db288ed82
      persistentVolumeReclaimPolicy: Delete
      storageClassName: csi-disk

    Pay attention to the fields in bold and red. The parameters are described as follows:

    Table 1 EVS volume configuration parameters

    Parameter

    Description

    failure-domain.beta.kubernetes.io/region

    Region where the EVS disk is located. Use the same value as that of the FlexVolume PV.

    failure-domain.beta.kubernetes.io/zone

    AZ where the EVS disk is located. Use the same value as that of the FlexVolume PV.

    name

    Name of the PV, which must be unique in the cluster.

    storage

    EVS volume capacity in the unit of Gi. Use the value of spec.capacity.storage of the FlexVolume PV.

    driver

    Storage driver used to attach the volume. Set the driver to disk.csi.everest.io for the EVS volume.

    volumeHandle

    Volume ID of the EVS disk. Use the value of spec.flexVolume.options.volumeID of the FlexVolume PV.

    everest.io/disk-mode

    EVS disk mode. Use the value of spec.flexVolume.options.disk-mode of the FlexVolume PV.

    everest.io/disk-volume-type

    EVS disk type. Currently, high I/O (SAS) and ultra-high I/O (SSD) are supported. Use the value of kubernetes.io/volumetype in the storage class corresponding to spec.storageClassName of the FlexVolume PV.

    storageClassName

    Name of the Kubernetes storage class associated with the storage volume. Set this field to csi-disk for EVS disks.

    Configuration example of a PV for an SFS volume:

    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv-sfs-example
      annotations:
        pv.kubernetes.io/provisioned-by: everest-csi-provisioner
    spec:
      accessModes:
      - ReadWriteMany
      capacity:
        storage: 10Gi
      csi:
        driver: nas.csi.everest.io
        fsType: nfs
        volumeAttributes:
          everest.io/share-export-location: sfs-nas01.ap-southeast-1.myhuaweicloud.com:/share-436304e8 
          storage.kubernetes.io/csiProvisionerIdentity: everest-csi-provisioner
        volumeHandle: 682f00bb-ace0-41d8-9b3e-913c9aa6b695
      persistentVolumeReclaimPolicy: Delete
      storageClassName: csi-nas

    Pay attention to the fields in bold and red. The parameters are described as follows:

    Table 2 SFS volume configuration parameters

    Parameter

    Description

    name

    Name of the PV, which must be unique in the cluster.

    storage

    File storage size in the unit of Gi. Use the value of spec.capacity.storage of the FlexVolume PV.

    driver

    Storage driver used to attach the volume. Set the driver to nas.csi.everest.io for the file system.

    everest.io/share-export-location

    Shared path of the file system. Use the value of spec.flexVolume.options.deviceMountPath of the FlexVolume PV.

    volumeHandle

    File system ID. Use the value of spec.flexVolume.options.volumeID of the FlexVolume PV.

    storageClassName

    Name of the Kubernetes storage class. Set this field to csi-nas.

    Configuration example of a PV for an OBS volume:

    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv-obs-example
      annotations:
        pv.kubernetes.io/provisioned-by: everest-csi-provisioner
    spec:
      accessModes:
      - ReadWriteMany
      capacity:
        storage: 1Gi
      csi:
        driver: obs.csi.everest.io
        fsType: s3fs
        volumeAttributes:
          everest.io/obs-volume-type: STANDARD
          everest.io/region: ap-southeast-1
          storage.kubernetes.io/csiProvisionerIdentity: everest-csi-provisioner
        volumeHandle: obs-normal-static-pv
      persistentVolumeReclaimPolicy: Delete
      storageClassName: csi-obs

    Pay attention to the fields in bold and red. The parameters are described as follows:

    Table 3 OBS volume configuration parameters

    Parameter

    Description

    name

    Name of the PV, which must be unique in the cluster.

    storage

    Storage capacity, in the unit of Gi. Set this parameter to the fixed value 1Gi.

    driver

    Storage driver used to attach the volume. Set the driver to obs.csi.everest.io for the OBS volume.

    fsType

    File type. Value options are obsfs or s3fs. If the value is s3fs, an OBS bucket is created and mounted using s3fs. If the value is obsfs, an OBS parallel file system is created and mounted using obsfs. Set this parameter according to the value of spec.flexVolume.options.posix of the FlexVolume PV. If the value of spec.flexVolume.options.posix is true, set this parameter to obsfs. If the value is false, set this parameter to s3fs.

    everest.io/obs-volume-type

    Storage class, including STANDARD (standard bucket) and WARM (infrequent access bucket). Set this parameter according to the value of spec.flexVolume.options.storage_class of the FlexVolume PV. If the value of spec.flexVolume.options.storage_class is standard, set this parameter to STANDARD. If the value is standard_ia, set this parameter to WARM.

    everest.io/region

    Region where the OBS bucket is located. Use the value of spec.flexVolume.options.region of the FlexVolume PV.

    volumeHandle

    OBS bucket name. Use the value of spec.flexVolume.options.volumeID of the FlexVolume PV.

    storageClassName

    Name of the Kubernetes storage class. Set this field to csi-obs.

    Configuration example of a PV for an SFS Turbo volume:

    apiVersion: v1
    kind: PersistentVolume
    metadata:
      name: pv-efs-example
      annotations:
        pv.kubernetes.io/provisioned-by: everest-csi-provisioner
    spec:
      accessModes:
      - ReadWriteMany
      capacity:
        storage: 10Gi
      csi:
        driver: sfsturbo.csi.everest.io
        fsType: nfs
        volumeAttributes:
          everest.io/share-export-location: 192.168.0.169:/
          storage.kubernetes.io/csiProvisionerIdentity: everest-csi-provisioner
        volumeHandle: 8962a2a2-a583-4b7f-bb74-fe76712d8414
      persistentVolumeReclaimPolicy: Delete
      storageClassName: csi-sfsturbo

    Pay attention to the fields in bold and red. The parameters are described as follows:

    Table 4 SFS Turbo volume configuration parameters

    Parameter

    Description

    name

    Name of the PV, which must be unique in the cluster.

    storage

    File system size. Use the value of spec.capacity.storage of the FlexVolume PV.

    driver

    Storage driver used to attach the volume. Set it to sfsturbo.csi.everest.io.

    everest.io/share-export-location

    Shared path of the SFS Turbo volume. Use the value of spec.flexVolume.options.deviceMountPath of the FlexVolume PV.

    volumeHandle

    SFS Turbo volume ID. Use the value of spec.flexVolume.options.volumeID of the FlexVolume PV.

    storageClassName

    Name of the Kubernetes storage class. Set this field to csi-sfsturbo for SFS Turbo volumes.

  3. Configure a YAML file of the PVC in the CSI format according to the PVC in the FlexVolume format and associate the PVC with the PV created in 2.

    To be specific, run the following commands to configure the pvc-example.yaml file, which is used to create a PVC.

    touch pvc-example.yaml

    vi pvc-example.yaml

    Configuration example of a PVC for an EVS volume:

    apiVersion: v1  
    kind: PersistentVolumeClaim
    metadata:
      labels:
        failure-domain.beta.kubernetes.io/region: ap-southeast-1
        failure-domain.beta.kubernetes.io/zone: <zone name>
      annotations:
        everest.io/disk-volume-type: SAS
        volume.beta.kubernetes.io/storage-provisioner: everest-csi-provisioner
      name: pvc-evs-example
      namespace: default
    spec:
      accessModes:
      - ReadWriteOnce
      resources:
        requests:
          storage: 10Gi
      volumeName:  pv-evs-example
      storageClassName: csi-disk

    Pay attention to the fields in bold and red. The parameters are described as follows:

    Table 5 PVC configuration parameters for an EVS volume

    Parameter

    Description

    failure-domain.beta.kubernetes.io/region

    Region where the cluster is located. Use the same value as that of the FlexVolume PVC.

    failure-domain.beta.kubernetes.io/zone

    AZ where the EVS disk is deployed. Use the same value as that of the FlexVolume PVC.

    everest.io/disk-volume-type

    Storage class of the EVS disk. The value can be SAS or SSD. Set this parameter to the same value as that of the PV created in 2.

    name

    PVC name, which must be unique in the namespace. The value must be unique in the namespace. (If the PVC is dynamically created by a stateful application, the value of this parameter must be the same as the name of the FlexVolume PVC.)

    namespace

    Namespace to which the PVC belongs. Use the same value as that of the FlexVolume PVC.

    storage

    Requested capacity of the PVC, which must be the same as the storage size of the existing PV.

    volumeName

    Name of the PV. Set this parameter to the name of the static PV in 2.

    storageClassName

    Name of the Kubernetes storage class. Set this field to csi-disk for EVS disks.

    Configuration example of a PVC for an SFS volume:

    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      annotations:
        volume.beta.kubernetes.io/storage-provisioner: everest-csi-provisioner
      name: pvc-sfs-example
      namespace: default
    spec:
      accessModes:
      - ReadWriteMany
      resources:
        requests:
          storage: 10Gi
      storageClassName: csi-nas
      volumeName: pv-sfs-example

    Pay attention to the fields in bold and red. The parameters are described as follows:

    Table 6 PVC configuration parameters for an SFS volume

    Parameter

    Description

    name

    PVC name, which must be unique in the namespace. The value must be unique in the namespace. (If the PVC is dynamically created by a stateful application, the value of this parameter must be the same as the name of the FlexVolume PVC.)

    namespace

    Namespace to which the PVC belongs. Use the same value as that of the FlexVolume PVC.

    storage

    Storage capacity, in the unit of Gi. The value must be the same as the storage size of the existing PV.

    storageClassName

    Set this field to csi-nas.

    volumeName

    Name of the PV. Set this parameter to the name of the static PV in 2.

    Configuration example of a PVC for an OBS volume:

    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      annotations:
        volume.beta.kubernetes.io/storage-provisioner: everest-csi-provisioner
        everest.io/obs-volume-type: STANDARD
        csi.storage.k8s.io/fstype: s3fs
      name: pvc-obs-example
      namespace: default
    spec:
      accessModes:
      - ReadWriteMany
      resources:
        requests:
          storage: 1Gi
      storageClassName: csi-obs
      volumeName: pv-obs-example

    Pay attention to the fields in bold and red. The parameters are described as follows:

    Table 7 PVC configuration parameters for an OBS volume

    Parameter

    Description

    everest.io/obs-volume-type

    OBS volume type, which can be STANDARD (standard bucket) and WARM (infrequent access bucket). Set this parameter to the same value as that of the PV created in 2.

    csi.storage.k8s.io/fstype

    File type, which can be obsfs or s3fs. The value must be the same as that of fsType of the static OBS volume PV.

    name

    PVC name, which must be unique in the namespace. The value must be unique in the namespace. (If the PVC is dynamically created by a stateful application, the value of this parameter must be the same as the name of the FlexVolume PVC.)

    namespace

    Namespace to which the PVC belongs. Use the same value as that of the FlexVolume PVC.

    storage

    Storage capacity, in the unit of Gi. Set this parameter to the fixed value 1Gi.

    storageClassName

    Name of the Kubernetes storage class. Set this field to csi-obs.

    volumeName

    Name of the PV. Set this parameter to the name of the static PV created in 2.

    Configuration example of a PVC for an SFS Turbo volume:

    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      annotations:
        volume.beta.kubernetes.io/storage-provisioner: everest-csi-provisioner
      name: pvc-efs-example
      namespace: default
    spec:
      accessModes:
      - ReadWriteMany
      resources:
        requests:
          storage: 10Gi
      storageClassName: csi-sfsturbo
      volumeName: pv-efs-example

    Pay attention to the fields in bold and red. The parameters are described as follows:

    Table 8 PVC configuration parameters for an SFS Turbo volume

    Parameter

    Description

    name

    PVC name, which must be unique in the namespace. The value must be unique in the namespace. (If the PVC is dynamically created by a stateful application, the value of this parameter must be the same as the name of the FlexVolume PVC.)

    namespace

    Namespace to which the PVC belongs. Use the same value as that of the FlexVolume PVC.

    storageClassName

    Name of the Kubernetes storage class. Set this field to csi-sfsturbo.

    storage

    Storage capacity, in the unit of Gi. The value must be the same as the storage size of the existing PV.

    volumeName

    Name of the PV. Set this parameter to the name of the static PV created in 2.

  4. Upgrade the workload to use a new PVC.

    For Deployments
    1. Run the kubectl create -f commands to create a PV and PVC.

      kubectl create -f pv-example.yaml

      kubectl create -f pvc-example.yaml

      Replace the example file name pvc-example.yaml in the preceding commands with the names of the YAML files configured in 2 and 3.

    2. Go to the CCE console. On the workload upgrade page, click Upgrade > Advanced Settings > Data Storage > Cloud Storage.

    3. Uninstall the old storage and add the PVC in the CSI format. Retain the original mounting path in the container.
    4. Click Submit.
    5. Wait until the pods are running.

    For StatefulSets that use existing storage

    1. Run the kubectl create -f commands to create a PV and PVC.

      kubectl create -f pv-example.yaml

      kubectl create -f pvc-example.yaml

      Replace the example file name pvc-example.yaml in the preceding commands with the names of the YAML files configured in 2 and 3.

    2. Run the kubectl edit command to edit the StatefulSet and use the newly created PVC.

      kubectl edit sts sts-example -n xxx

      Replace sts-example in the preceding command with the actual name of the StatefulSet to upgrade. xxx indicates the namespace to which the StatefulSet belongs.

    3. Wait until the pods are running.

    The current console does not support the operation of adding new cloud storage for StatefulSets. Use the kubectl commands to replace the storage with the newly created PVC.

    For StatefulSets that use dynamically allocated storage

    1. Back up the PV and PVC in the flexVolume format used by the StatefulSet.

      kubectl get pvc xxx -n {namespaces} -oyaml > pvc-backup.yaml

      kubectl get pv xxx -n {namespaces} -oyaml > pv-backup.yaml

    2. Change the number of pods to 0.
    3. On the storage page, disassociate the flexVolume PVC used by the StatefulSet.
    4. Run the kubectl create -f commands to create a PV and PVC.

      kubectl create -f pv-example.yaml

      kubectl create -f pvc-example.yaml

      Replace the example file name pvc-example.yaml in the preceding commands with the names of the YAML files configured in 2 and 3.

    5. Change the number of pods back to the original value and wait until the pods are running.

    The dynamic allocation of storage for StatefulSets is achieved by using volumeClaimTemplates. This field cannot be modified by Kubernetes. Therefore, data cannot be migrated by using a new PVC.

    The PVC naming rule of the volumeClaimTemplates is fixed. When a PVC that meets the naming rule exists, this PVC is used.

    Therefore, disassociate the original PVC first, and then create a PVC with the same name in the CSI format.

    6. (Optional) Recreate the stateful application to ensure that a CSI PVC is used when the application is scaled out. Otherwise, FlexVolume PVCs are used in scaling out.

    • Run the following command to obtain the YAML file of the StatefulSet:

    kubectl get sts xxx -n {namespaces} -oyaml > sts.yaml

    • Run the following command to back up the YAML file of the StatefulSet:

    cp sts.yaml sts-backup.yaml

    • Modify the definition of volumeClaimTemplates in the YAML file of the StatefulSet.

    vi sts.yaml

    Configuration example of volumeClaimTemplates for an EVS volume:

      volumeClaimTemplates:
        - metadata:
            name: pvc-161070049798261342
            namespace: default
            creationTimestamp: null
            annotations:
              everest.io/disk-volume-type: SAS
          spec:
            accessModes:
              - ReadWriteOnce
            resources:
              requests:
                storage: 10Gi
            storageClassName: csi-disk

    The parameter value must be the same as the PVC of the EVS volume created in 3.

    Configuration example of volumeClaimTemplates for an SFS volume:

      volumeClaimTemplates:
        - metadata:
            name: pvc-161063441560279697
            namespace: default
            creationTimestamp: null
          spec:
            accessModes:
              - ReadWriteMany
            resources:
              requests:
                storage: 10Gi
            storageClassName: csi-nas

    The parameter value must be the same as the PVC of the SFS volume created in 3.

    Configuration example of volumeClaimTemplates for an OBS volume:

      volumeClaimTemplates:
        - metadata:
            name: pvc-161070100417416148
            namespace: default
            creationTimestamp: null
            annotations:
              csi.storage.k8s.io/fstype: s3fs
              everest.io/obs-volume-type: STANDARD
          spec:
            accessModes:
              - ReadWriteMany
            resources:
              requests:
                storage: 1Gi
            storageClassName: csi-obs

    The parameter value must be the same as the PVC of the OBS volume created in 3.

    • Delete the StatefulSet.

    kubectl delete sts xxx -n {namespaces}

    • Create the StatefulSet.

    kubectl create -f sts.yaml

  5. Check service functions.

    1. Check whether the application is running properly.
    2. Checking whether the data storage is normal.

    If a rollback is required, perform 4. Select the PVC in FlexVolume format and upgrade the application.

  6. Uninstall the PVC in the FlexVolume format.

    If the application functions normally, unbind the PVC in the FlexVolume format on the storage management page.

    You can also run the kubectl command to delete the PVC and PV of the FlexVolume format.

    Before deleting a PV, change the persistentVolumeReclaimPolicy of the PV to Retain. Otherwise, the underlying storage will be reclaimed after the PV is deleted.

    If the cluster has been upgraded before the storage migration, PVs may fail to be deleted. You can remove the PV protection field finalizers to delete PVs.

    kubectl patch pv {pv_name} -p '{"metadata":{"finalizers":null}}'