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

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: eu-west-0
       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. 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:  # Shared path of the file storage
         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: eu-west-0
         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: eu-west-0
       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}}'