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Home Page Container Service for Kubernetes ACK Managed and Dedicated Clusters User Guide Storage Upgrade from FlexVolume to CSI Migrate statically provisioned OSS volumes from Flexvolume to CSI

Migrate statically provisioned OSS volumes from FlexVolume to CSI

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Migrate statically provisioned OSS volumes from FlexVolume to CSI by recreating PVCs and PVs on an existing ACK cluster.

Applies only to clusters with statically provisioned OSS volumes on FlexVolume. If your cluster also has disk volumes on FlexVolume, see Use csi-compatible-controller to migrate from FlexVolume to CSI.

How CSI and FlexVolume differ

Plugin

Components

kubelet parameter

CSI

CSI-Provisioner (Deployment): handles volume creation, snapshots, Container Network File System (CNFS) storage, and data restoration after accidental deletion. CSI-Plugin (DaemonSet): mounts and unmounts disk, NAS, and OSS volumes.

Set enable-controller-attach-detach to true on each node.

FlexVolume

Disk-Controller (Deployment): handles volume creation. FlexVolume (DaemonSet): mounts and unmounts disk, NAS, and OSS volumes.

Set enable-controller-attach-detach to true on each node.

Usage notes

PVCs are recreated during migration, which restarts pods and interrupts workloads. Perform migration during off-peak hours.

Prerequisites

  • An ACK cluster with FlexVolume installed and at least one statically provisioned OSS volume

  • kubectl access to create, get, list, and delete PVCs, PVs, Deployments, and DaemonSets in the kube-system namespace

  • Access to OpenAPI Explorer to call UnInstallClusterAddons and InstallClusterAddons

Migrate statically provisioned OSS volumes from FlexVolume to CSI

The following example uses a StatefulSet workload to migrate a statically provisioned OSS volume from FlexVolume to CSI.

oss

Step 1: Install CSI manually

Deploy the CSI components alongside the existing FlexVolume installation.

  1. Create two files: csi-plugin.yaml and csi-provisioner.yaml. csi-plugin.yaml

    ---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: csi-admin
  namespace: kube-system
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: alicloud-csi-plugin
rules:
  - apiGroups: [""]
    resources: ["secrets"]
    verbs: ["get", "create", "list"]
  - apiGroups: [""]
    resources: ["persistentvolumes"]
    verbs: ["get", "list", "watch", "update", "create", "delete", "patch"]
  - apiGroups: [""]
    resources: ["persistentvolumeclaims"]
    verbs: ["get", "list", "watch", "update"]
  - apiGroups: [""]
    resources: ["persistentvolumeclaims/status"]
    verbs: ["get", "list", "watch", "update", "patch"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["storageclasses"]
    verbs: ["get", "list", "watch"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["csinodes"]
    verbs: ["get", "list", "watch"]
  - apiGroups: [""]
    resources: ["events"]
    verbs: ["get", "list", "watch", "create", "update", "patch"]
  - apiGroups: [""]
    resources: ["endpoints"]
    verbs: ["get", "watch", "list", "delete", "update", "create"]
  - apiGroups: [""]
    resources: ["configmaps"]
    verbs: ["get", "watch", "list", "delete", "update", "create"]
  - apiGroups: [""]
    resources: ["nodes"]
    verbs: ["get", "list", "watch", "update"]
  - apiGroups: ["csi.storage.k8s.io"]
    resources: ["csinodeinfos"]
    verbs: ["get", "list", "watch"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["volumeattachments"]
    verbs: ["get", "list", "watch", "update", "patch"]
  - apiGroups: ["snapshot.storage.k8s.io"]
    resources: ["volumesnapshotclasses"]
    verbs: ["get", "list", "watch", "create"]
  - apiGroups: ["snapshot.storage.k8s.io"]
    resources: ["volumesnapshotcontents"]
    verbs: ["create", "get", "list", "watch", "update", "delete"]
  - apiGroups: ["snapshot.storage.k8s.io"]
    resources: ["volumesnapshots"]
    verbs: ["get", "list", "watch", "update", "create"]
  - apiGroups: ["apiextensions.k8s.io"]
    resources: ["customresourcedefinitions"]
    verbs: ["create", "list", "watch", "delete", "get", "update", "patch"]
  - apiGroups: ["coordination.k8s.io"]
    resources: ["leases"]
    verbs: ["get", "create", "list", "watch", "delete", "update"]
  - apiGroups: ["snapshot.storage.k8s.io"]
    resources: ["volumesnapshotcontents/status"]
    verbs: ["update"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["volumeattachments/status"]
    verbs: ["patch"]
  - apiGroups: ["snapshot.storage.k8s.io"]
    resources: ["volumesnapshots/status"]
    verbs: ["update"]
  - apiGroups: ["storage.k8s.io"]
    resources: ["storageclasses"]
    verbs: ["get", "list", "watch"]
  - apiGroups: [""]
    resources: ["namespaces"]
    verbs: ["get", "list"]
  - apiGroups: [""]
    resources: ["pods","pods/exec"]
    verbs: ["create", "delete", "get", "post", "list", "watch", "patch", "update"]
  - apiGroups: ["storage.alibabacloud.com"]
    resources: ["rules"]
    verbs: ["get"]
  - apiGroups: ["storage.alibabacloud.com"]
    resources: ["containernetworkfilesystems"]
    verbs: ["get","list", "watch"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: alicloud-csi-plugin
subjects:
  - kind: ServiceAccount
    name: csi-admin
    namespace: kube-system
roleRef:
  kind: ClusterRole
  name: alicloud-csi-plugin
  apiGroup: rbac.authorization.k8s.io
---
apiVersion: storage.k8s.io/v1
kind: CSIDriver
metadata:
  name: diskplugin.csi.alibabacloud.com
spec:
  attachRequired: true
  podInfoOnMount: true
---
apiVersion: storage.k8s.io/v1
kind: CSIDriver
metadata:
  name: nasplugin.csi.alibabacloud.com
spec:
  attachRequired: false
  podInfoOnMount: true
---
apiVersion: storage.k8s.io/v1
kind: CSIDriver
metadata:
  name: ossplugin.csi.alibabacloud.com
spec:
  attachRequired: false
  podInfoOnMount: true
---
kind: DaemonSet
apiVersion: apps/v1
metadata:
  name: csi-plugin
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app: csi-plugin
  template:
    metadata:
      labels:
        app: csi-plugin
    spec:
      tolerations:
        - operator: Exists
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: type
                operator: NotIn
                values:
                - virtual-kubelet
      nodeSelector:
        kubernetes.io/os: linux
      serviceAccount: csi-admin
      priorityClassName: system-node-critical
      hostNetwork: true
      hostPID: true
      dnsPolicy: ClusterFirst
      containers:
        - name: disk-driver-registrar
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-node-driver-registrar:v2.3.1-038aeb6-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 1024Mi
          args:
            - "--v=5"
            - "--csi-address=/var/lib/kubelet/csi-plugins/diskplugin.csi.alibabacloud.com/csi.sock"
            - "--kubelet-registration-path=/var/lib/kubelet/csi-plugins/diskplugin.csi.alibabacloud.com/csi.sock"
          volumeMounts:
            - name: kubelet-dir
              mountPath: /var/lib/kubelet
            - name: registration-dir
              mountPath: /registration
        - name: nas-driver-registrar
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-node-driver-registrar:v2.3.1-038aeb6-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 1024Mi
          args:
            - "--v=5"
            - "--csi-address=/var/lib/kubelet/csi-plugins/nasplugin.csi.alibabacloud.com/csi.sock"
            - "--kubelet-registration-path=/var/lib/kubelet/csi-plugins/nasplugin.csi.alibabacloud.com/csi.sock"
          volumeMounts:
            - name: kubelet-dir
              mountPath: /var/lib/kubelet/
            - name: registration-dir
              mountPath: /registration
        - name: oss-driver-registrar
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-node-driver-registrar:v2.3.1-038aeb6-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 1024Mi
          args:
            - "--v=5"
            - "--csi-address=/var/lib/kubelet/csi-plugins/ossplugin.csi.alibabacloud.com/csi.sock"
            - "--kubelet-registration-path=/var/lib/kubelet/csi-plugins/ossplugin.csi.alibabacloud.com/csi.sock"
          volumeMounts:
            - name: kubelet-dir
              mountPath: /var/lib/kubelet/
            - name: registration-dir
              mountPath: /registration
        - name: csi-plugin
          securityContext:
            privileged: true
            allowPrivilegeEscalation: true
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-plugin:v1.24.6-55c95dd-aliyun
          args:
            - "--endpoint=$(CSI_ENDPOINT)"
            - "--v=2"
            - "--driver=oss,nas,disk"
          env:
            - name: KUBE_NODE_NAME
              valueFrom:
                fieldRef:
                  apiVersion: v1
                  fieldPath: spec.nodeName
            - name: CSI_ENDPOINT
              value: unix://var/lib/kubelet/csi-plugins/driverplugin.csi.alibabacloud.com-replace/csi.sock
            - name: MAX_VOLUMES_PERNODE
              value: "15"
            - name: SERVICE_TYPE
              value: "plugin"
          resources:
            requests:
              cpu: 100m
              memory: 128Mi
            limits:
              cpu: 500m
              memory: 1024Mi
          livenessProbe:
            httpGet:
              path: /healthz
              port: healthz
              scheme: HTTP
            initialDelaySeconds: 10
            periodSeconds: 30
            timeoutSeconds: 5
            failureThreshold: 5
          readinessProbe:
            httpGet:
              path: /healthz
              port: healthz
            initialDelaySeconds: 10
            periodSeconds: 30
            timeoutSeconds: 5
            failureThreshold: 5
          ports:
            - name: healthz
              containerPort: 11260
          volumeMounts:
            - name: kubelet-dir
              mountPath: /var/lib/kubelet/
              mountPropagation: "Bidirectional"
            - name: etc
              mountPath: /host/etc
            - name: host-log
              mountPath: /var/log/
            - name: ossconnectordir
              mountPath: /host/usr/
            - name: container-dir
              mountPath: /var/lib/container
              mountPropagation: "Bidirectional"
            - name: host-dev
              mountPath: /dev
              mountPropagation: "HostToContainer"
            - mountPath: /var/addon
              name: addon-token
              readOnly: true
            - mountPath: /host/var/run/
              name: fuse-metrics-dir
      volumes:
        - name: fuse-metrics-dir
          hostPath:
            path: /var/run/
            type: DirectoryOrCreate
        - name: registration-dir
          hostPath:
            path: /var/lib/kubelet/plugins_registry
            type: DirectoryOrCreate
        - name: container-dir
          hostPath:
            path: /var/lib/container
            type: DirectoryOrCreate
        - name: kubelet-dir
          hostPath:
            path: /var/lib/kubelet
            type: Directory
        - name: host-dev
          hostPath:
            path: /dev
        - name: host-log
          hostPath:
            path: /var/log/
        - name: etc
          hostPath:
            path: /etc
        - name: ossconnectordir
          hostPath:
            path: /usr/
        - name: addon-token
          secret:
            defaultMode: 420
            optional: true
            items:
            - key: addon.token.config
              path: token-config
            secretName: addon.csi.token
  updateStrategy:
    rollingUpdate:
      maxUnavailable: 30%
    type: RollingUpdate

    csi-provisioner.yaml

    ---
kind: Deployment
apiVersion: apps/v1
metadata:
  name: csi-provisioner
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app: csi-provisioner
  strategy:
    rollingUpdate:
      maxSurge: 0
      maxUnavailable: 1
    type: RollingUpdate
  replicas: 2
  template:
    metadata:
      labels:
        app: csi-provisioner
    spec:
      affinity:
        nodeAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 1
            preference:
              matchExpressions:
              - key: node-role.kubernetes.io/master
                operator: Exists
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: type
                operator: NotIn
                values:
                - virtual-kubelet
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 100
            podAffinityTerm:
              labelSelector:
                matchExpressions:
                - key: app
                  operator: In
                  values:
                  - csi-provisioner
              topologyKey: kubernetes.io/hostname
      tolerations:
      - effect: NoSchedule
        operator: Exists
        key: node-role.kubernetes.io/master
      - effect: NoSchedule
        operator: Exists
        key: node.cloudprovider.kubernetes.io/uninitialized
      serviceAccount: csi-admin
      hostPID: true
      priorityClassName: system-node-critical
      containers:
        - name: external-disk-provisioner
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-provisioner:v3.0.0-080f01e64-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 1024Mi
          args:
            - "--csi-address=$(ADDRESS)"
            - "--feature-gates=Topology=True"
            - "--volume-name-prefix=disk"
            - "--strict-topology=true"
            - "--timeout=150s"
            - "--leader-election=true"
            - "--retry-interval-start=500ms"
            - "--extra-create-metadata=true"
            - "--default-fstype=ext4"
            - "--v=5"
          env:
            - name: ADDRESS
              value: /var/lib/kubelet/csi-provisioner/diskplugin.csi.alibabacloud.com/csi.sock
          volumeMounts:
            - name: disk-provisioner-dir
              mountPath: /var/lib/kubelet/csi-provisioner/diskplugin.csi.alibabacloud.com
        - name: external-disk-attacher
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-attacher:v3.3-72dd428b-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 1024Mi
          args:
            - "--v=5"
            - "--csi-address=$(ADDRESS)"
            - "--leader-election=true"
          env:
            - name: ADDRESS
              value: /var/lib/kubelet/csi-provisioner/diskplugin.csi.alibabacloud.com/csi.sock
          volumeMounts:
            - name: disk-provisioner-dir
              mountPath: /var/lib/kubelet/csi-provisioner/diskplugin.csi.alibabacloud.com
        - name: external-disk-resizer
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-resizer:v1.3-ca84e84-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 8Gi
          args:
            - "--v=5"
            - "--csi-address=$(ADDRESS)"
            - "--leader-election"
          env:
            - name: ADDRESS
              value: /var/lib/kubelet/csi-provisioner/diskplugin.csi.alibabacloud.com/csi.sock
          volumeMounts:
            - name: disk-provisioner-dir
              mountPath: /var/lib/kubelet/csi-provisioner/diskplugin.csi.alibabacloud.com
        - name: external-nas-provisioner
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-provisioner:v3.0.0-080f01e64-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 1024Mi
          args:
            - "--csi-address=$(ADDRESS)"
            - "--volume-name-prefix=nas"
            - "--timeout=150s"
            - "--leader-election=true"
            - "--retry-interval-start=500ms"
            - "--default-fstype=nfs"
            - "--v=5"
          env:
            - name: ADDRESS
              value: /var/lib/kubelet/csi-provisioner/nasplugin.csi.alibabacloud.com/csi.sock
          volumeMounts:
            - name: nas-provisioner-dir
              mountPath: /var/lib/kubelet/csi-provisioner/nasplugin.csi.alibabacloud.com
        - name: external-nas-resizer
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-resizer:v1.3-ca84e84-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 8Gi
          args:
            - "--v=5"
            - "--csi-address=$(ADDRESS)"
            - "--leader-election"
          env:
            - name: ADDRESS
              value: /var/lib/kubelet/csi-provisioner/nasplugin.csi.alibabacloud.com/csi.sock
          volumeMounts:
            - name: nas-provisioner-dir
              mountPath: /var/lib/kubelet/csi-provisioner/nasplugin.csi.alibabacloud.com
        - name: external-oss-provisioner
          args:
            - --csi-address=$(ADDRESS)
            - --volume-name-prefix=oss
            - --timeout=150s
            - --leader-election=true
            - --retry-interval-start=500ms
            - --default-fstype=ossfs
            - --v=5
          env:
          - name: ADDRESS
            value: /var/lib/kubelet/csi-provisioner/ossplugin.csi.alibabacloud.com/csi.sock
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-provisioner:v3.0.0-080f01e64-aliyun
          resources:
            limits:
              cpu: 500m
              memory: 1Gi
            requests:
              cpu: 10m
              memory: 16Mi
          volumeMounts:
          - mountPath: /var/lib/kubelet/csi-provisioner/ossplugin.csi.alibabacloud.com
            name: oss-provisioner-dir
        - name: external-csi-snapshotter
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-snapshotter:v4.0.0-a230d5b3-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 1024Mi
          args:
            - "--v=5"
            - "--csi-address=$(ADDRESS)"
            - "--leader-election=true"
            - "--extra-create-metadata=true"
          env:
            - name: ADDRESS
              value: /csi/csi.sock
          volumeMounts:
            - name: disk-provisioner-dir
              mountPath: /csi
        - name: external-snapshot-controller
          image: registry.cn-hangzhou.aliyuncs.com/acs/snapshot-controller:v4.0.0-a230d5b3-aliyun
          resources:
            requests:
              cpu: 10m
              memory: 16Mi
            limits:
              cpu: 500m
              memory: 1024Mi
          args:
            - "--v=5"
            - "--leader-election=true"
        - name: csi-provisioner
          securityContext:
            privileged: true
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-plugin:v1.24.6-55c95dd-aliyun
          args:
            - "--endpoint=$(CSI_ENDPOINT)"
            - "--v=2"
            - "--driver=nas,disk,oss"
          env:
            - name: CSI_ENDPOINT
              value: unix://var/lib/kubelet/csi-provisioner/driverplugin.csi.alibabacloud.com-replace/csi.sock
            - name: MAX_VOLUMES_PERNODE
              value: "15"
            - name: SERVICE_TYPE
              value: "provisioner"
            - name: "CLUSTER_ID"
              value: "CLUSTER_ID"
          livenessProbe:
            httpGet:
              path: /healthz
              port: healthz
              scheme: HTTP
            initialDelaySeconds: 10
            periodSeconds: 30
            timeoutSeconds: 5
            failureThreshold: 5
          readinessProbe:
            httpGet:
              path: /healthz
              port: healthz
            initialDelaySeconds: 5
            periodSeconds: 20
          ports:
            - name: healthz
              containerPort: 11270
          volumeMounts:
            - name: host-log
              mountPath: /var/log/
            - name: disk-provisioner-dir
              mountPath: /var/lib/kubelet/csi-provisioner/diskplugin.csi.alibabacloud.com
            - name: nas-provisioner-dir
              mountPath: /var/lib/kubelet/csi-provisioner/nasplugin.csi.alibabacloud.com
            - name: oss-provisioner-dir
              mountPath: /var/lib/kubelet/csi-provisioner/ossplugin.csi.alibabacloud.com
            - mountPath: /var/addon
              name: addon-token
              readOnly: true
            - mountPath: /mnt
              mountPropagation: Bidirectional
              name: host-dev
            - mountPath: /host/etc
              name: etc
          resources:
            limits:
              cpu: 500m
              memory: 1024Mi
            requests:
              cpu: 100m
              memory: 128Mi
      volumes:
        - name: disk-provisioner-dir
          emptyDir: {}
        - name: nas-provisioner-dir
          emptyDir: {}
        - name: oss-provisioner-dir
          emptyDir: {}
        - name: host-log
          hostPath:
            path: /var/log/
        - name: etc
          hostPath:
            path: /etc
            type: ""
        - name: host-dev
          hostPath:
            path: /mnt
            type: ""
        - name: addon-token
          secret:
            defaultMode: 420
            optional: true
            items:
            - key: addon.token.config
              path: token-config
            secretName: addon.csi.token

  2. Deploy both components:

    kubectl apply -f csi-plugin.yaml -f csi-provisioner.yaml

  3. Verify that CSI is running:

    kubectl get pods -nkube-system | grep csi

    Expected output:

    csi-plugin-577mm                              4/4     Running   0          3d20h
csi-plugin-k9mzt                              4/4     Running   0          41d
csi-provisioner-6b58f46989-8wwl5              9/9     Running   0          41d
csi-provisioner-6b58f46989-qzh8l              9/9     Running   0          6d20h

Step 2: Check the current volume status

Record the current state of your workload before converting PVCs and PVs.

  1. Check pod status:

    kubectl get pod

    Expected output:

    NAME       READY   STATUS    RESTARTS   AGE
oss-sts-1  1/1     Running   0          11m

  2. Identify the PVC used by the pod:

    kubectl describe pod oss-sts-1 |grep ClaimName

    Expected output:

    ClaimName:  oss-pvc

  3. Check the PVC status:

    kubectl get pvc

    Expected output:

    NAME      STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
oss-pvc   Bound    oss-pv   5Gi        RWX                           7m23s

Step 3: Create CSI-managed PVC and PV for the OSS volume

Choose one of the following methods:

Method 1: Automated (Flexvolume2CSI CLI)

Method 2: Manual YAML editing

Best for

Clusters with many PVs to convert

Clusters with a small number of PVs, or when you want full control

Effort

Low — the CLI generates the CSI YAML

Higher — edit YAML definitions by hand

Risk

Low — logical conversion only; original PV/PVC objects remain intact until you delete them

Low — same data, new PV/PVC definitions; original objects remain until cleanup

Downtime

Pod restarts when you update the application reference

Pod restarts when you update the application reference

Method 1: Automated conversion with the Flexvolume2CSI CLI

  1. Convert FlexVolume PVs and PVCs to CSI definitions with the Flexvolume2CSI CLI. The CLI generates oss-pv-pvc-csi.yaml.

  2. Apply the generated file:

    kubectl apply -f oss-pv-pvc-csi.yaml

  3. Verify that both the old and new PVCs are bound:

    kubectl get pvc

    Expected output:

    NAME          STATUS   VOLUME       CAPACITY   ACCESS MODES   STORAGECLASS   AGE
oss-pvc-csi   Bound    oss-pv-csi   5Gi        RWO                           7m15s
oss-pvc       Bound    oss-pv       5Gi        RWX                           52m

Method 2: Manual conversion by editing PVC and PV configurations

  1. Save the existing FlexVolume PVC definition:

    kubectl get pvc oss-pvc -oyaml > oss-pvc-flexvolume.yaml
cat oss-pvc-flexvolume.yaml

    Expected output:

    apiVersion: v1
kind: PersistentVolumeClaim
  name: oss-pvc
  namespace: default
spec:
  accessModes:
  - ReadWriteMany
  resources:
    requests:
      storage: 5Gi
  volumeMode: Filesystem
  volumeName: oss-pv

    Save the PV:

    kubectl get pv oss-pv -oyaml > oss-pv-flexvolume.yaml
cat oss-pv-flexvolume.yaml

    Expected output:

    apiVersion: v1
kind: PersistentVolume
metadata:
  name: oss-pv
spec:
  accessModes:
  - ReadWriteMany
  capacity:
    storage: 5Gi
  claimRef:
    apiVersion: v1
    kind: PersistentVolumeClaim
    name: oss-pvc
    namespace: default
  flexVolume:
    driver: alicloud/oss
    nodePublishSecretRef:
      name: oss-secret
      namespace: default
    options:
      bucket: xxx
      otherOpts: -o max_stat_cache_size=0 -o allow_other
      url: xxx.aliyuncs.com
  persistentVolumeReclaimPolicy: Retain
  volumeMode: Filesystem

  2. Create oss-pv-pvc-csi.yaml with CSI PVC and PV definitions. Replace *** with your OSS bucket name and endpoint.

    apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: oss-pvc-csi
spec:
  accessModes:
  - ReadWriteMany
  resources:
    requests:
      storage: 5Gi
  selector:
    matchLabels:
      alicloud-pvname: oss-pv-csi
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: oss-pv-csi
  labels:
    alicloud-pvname: oss-pv-csi
spec:
  capacity:
    storage: 5Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  csi:
    driver: ossplugin.csi.alibabacloud.com
    volumeHandle: oss-pv-csi
    nodePublishSecretRef:
      name: oss-secret
      namespace: default
    volumeAttributes:
      bucket: "***"
      url: "***.aliyuncs.com"
      otherOpts: "-o max_stat_cache_size=0 -o allow_other"

  3. Apply the file:

    kubectl apply -f oss-pv-pvc-csi.yaml

  4. Verify that both PVCs are bound:

    kubectl get pvc

    Expected output:

    NAME          STATUS   VOLUME       CAPACITY   ACCESS MODES   STORAGECLASS   AGE
oss-pvc-csi   Bound    oss-pv-csi   5Gi        RWO                           7m15s
oss-pvc       Bound    oss-pv       5Gi        RWX                           52m

Step 4: Update the application to use the CSI-managed PVC

  1. Edit the StatefulSet configuration:

    kubectl edit sts oss-sts

  2. Update the volume reference to the CSI PVC:

          volumes:
      - name: oss
        persistentVolumeClaim:
          claimName: oss-pvc-csi

  3. Verify the pod restarted:

    kubectl get pod

    Expected output:

    NAME       READY   STATUS    RESTARTS   AGE
oss-sts-1  1/1     Running   0          70s

  4. Verify the volume uses CSI (ossfs):

    kubectl exec oss-sts-1 -- mount |grep ossfs

    Expected output:

    ***:/ on /var/lib/kubelet/pods/ac02ea3f-125f-4b38-9bcf-9b117f62eaf0/volumes/kubernetes.io~csi/oss-pv-csi/mount type ossfs (rw,relatime,max_stat_cache_size=0,allow_other)

    The mount path kubernetes.io~csi confirms CSI is active.

Step 5: Uninstall FlexVolume

  1. Call UnInstallClusterAddons in OpenAPI Explorer to uninstall FlexVolume. See Uninstall components from a cluster.

    • ClusterId: The cluster ID from the Basic Information tab.

    • name: Set to flexvolume.

  2. Delete the FlexVolume controller components:

    kubectl delete deploy -n kube-system alicloud-disk-controller alicloud-nas-controller

  3. Verify that FlexVolume is fully removed:

    kubectl get pods -n kube-system | grep 'flexvolume\|alicloud-disk-controller\|alicloud-nas-controller'

    No output means FlexVolume is fully removed.

  4. Delete the FlexVolume StorageClasses (provisioner: alicloud/disk):

    kubectl delete storageclass alicloud-disk-available alicloud-disk-efficiency alicloud-disk-essd alicloud-disk-ssd

    Expected output:

    storageclass.storage.k8s.io "alicloud-disk-available" deleted
storageclass.storage.k8s.io "alicloud-disk-efficiency" deleted
storageclass.storage.k8s.io "alicloud-disk-essd" deleted
storageclass.storage.k8s.io "alicloud-disk-ssd" deleted

Step 6: Install CSI by using the API

Replace the manually deployed CSI components with the officially managed add-on.

  1. Call InstallClusterAddons in OpenAPI Explorer to install CSI. See Install a component in an ACK cluster.

    • ClusterId: Your cluster ID.

    • name: csi-provisioner

    • version: Applied automatically. See csi-provisioner for available versions.

  2. Verify that the CSI plug-in is running:

    kubectl get pods -nkube-system | grep csi

    Expected output:

    csi-plugin-577mm                              4/4     Running   0          3d20h
csi-plugin-k9mzt                              4/4     Running   0          41d
csi-provisioner-6b58f46989-8wwl5              9/9     Running   0          41d
csi-provisioner-6b58f46989-qzh8l              9/9     Running   0          6d20h

Step 7: Update kubelet parameters on existing nodes

CSI requires --enable-controller-attach-detach set to true on each node. The following DaemonSet applies this automatically.

Important

This DaemonSet restarts kubelet on each node, which may briefly interrupt pod scheduling. Drain nodes one at a time before deploying, or verify your workloads tolerate a brief kubelet restart. Delete the DaemonSet after this step.

kind: DaemonSet
apiVersion: apps/v1
metadata:
  name: kubelet-set
spec:
  selector:
    matchLabels:
      app: kubelet-set
  template:
    metadata:
      labels:
        app: kubelet-set
    spec:
      tolerations:
        - operator: "Exists"
      hostNetwork: true
      hostPID: true
      containers:
        - name: kubelet-set
          securityContext:
            privileged: true
            capabilities:
              add: ["SYS_ADMIN"]
            allowPrivilegeEscalation: true
          image: registry.cn-hangzhou.aliyuncs.com/acs/csi-plugin:v1.26.5-56d1e30-aliyun
          imagePullPolicy: "Always"
          env:
          - name: enableADController
            value: "true"
          command: ["sh", "-c"]
          args:
          - echo "Starting kubelet flag set to $enableADController";
            ifFlagTrueNum=`cat /host/etc/systemd/system/kubelet.service.d/10-kubeadm.conf | grep enable-controller-attach-detach=$enableADController | grep -v grep | wc -l`;
            echo "ifFlagTrueNum is $ifFlagTrueNum";
            if [ "$ifFlagTrueNum" = "0" ]; then
                curValue="true";
                if [ "$enableADController" = "true" ]; then
                    curValue="false";
                fi;
                sed -i "s/enable-controller-attach-detach=$curValue/enable-controller-attach-detach=$enableADController/" /host/etc/systemd/system/kubelet.service.d/10-kubeadm.conf;
                restartKubelet="true";
                echo "current value is $curValue, change to expect "$enableADController;
            fi;
            if [ "$restartKubelet" = "true" ]; then
                /nsenter --mount=/proc/1/ns/mnt systemctl daemon-reload;
                /nsenter --mount=/proc/1/ns/mnt service kubelet restart;
                echo "restart kubelet";
            fi;
            while true;
            do
                sleep 5;
            done;
          volumeMounts:
          - name: etc
            mountPath: /host/etc
      volumes:
        - name: etc
          hostPath:
            path: /etc

After all nodes have enable-controller-attach-detach=true, delete the DaemonSet:

kubectl delete daemonset kubelet-set

Next steps

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