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    CBS-CSI

    Last updated: 2024-02-05 10:22:05
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      Operation Scenario

      The CBS-CSI add-on allows you to select the storage class and create the corresponding PVs and PVCs of the CBS type in a TKE cluster on the console. This document introduces the features of the CBS-CSI add-on and some common use cases.

      Features

      Feature
      Description
      Static volume
      Supports manual creation of volumes, PV objects, and PVC objects.
      Dynamic volume
      Supports configuration, creation, and deletion of volumes and PV objects through StorageClass.
      Storage topology awareness
      CBS does not support cross-AZ mounting. In a cluster with multiple AZs, the CBS-CSI add-on will schedule pods first, and then volumes will be created in the AZ of the node where the pods are scheduled.
      Scheduler awareness of node maxAttachLimit
      By default, one Tencent CVM instance can mount up to 20 cloud disks. When scheduling pods, the scheduler will filter out nodes where the number of mounted cloud disks has exceeded the limit.
      Online volume expansion
      You can modify the PVC capacity field to implement online expansion (only the CBS type is supported).
      Volume snapshot and restoration
      Supports the creation of volumes through snapshots.

      Component Description

      After it is deployed in a cluster, the CBS-CSI add-on contains the following components:
      DaemonSet (NodePlugin): each node provides a DaemonSet. It consists of two containers, CBS-CSI Driver and node-driver-registrar. It is used to register the driver for the node and provide the ability to mount.
      StatefulSet and Deployment (Controller): consists of a driver and multiple sidecars (external-provisioner, external-attacher, external-resizer, external-snapshotter, and snapshot-controller). It provides functions, such as o create or delete volumes, attach or detach, expand, and take snapshot.
      
      
      

      Limits

      TKE cluster version 1.14 or later
      You can expand cloud disks online and create snapshots in a TKE cluster only after using the CBS-CSI add-on.
      You can continue to use QcloudCbs (In-Tree plugin) in your TKE cluster. (It will be integrated to CBS-CSI through Volume Migration in the future.)

      CBS-CSI Permission

      Note:
      The Permission Scenarios section only lists the permissions related to the core features of the components, for a complete permission list, please refer to the Permission Definition.

      Permission Description

      The permission of this component is the minimal dependency required for the current feature to operate.
      The related directory /var/lib/kubelet on the host machine needs to be mounted to the container to accomplish volume mount/unmount, hence the activation of the privileged-level container is required.

      Permission Scenarios

      Feature
      Involved Object
      Involved Operation Permission
      Perceiving the maximum number of disks that can be mounted on a node from the providerID in the Access Node resources
      node
      get/list
      Executing disk creation and deletion based on pvc/pv information
      pv/pvc/storageclasses/csinode
      get/list/watch/create/update/patch/delete
      Completing disk mounting and uninstallation based on volumeattachments resource objects
      volumeattachments/volumesnapshotclasses
      create/get/list/watch/update/delete
      Expanding disk capacity via snapshot
      pod/volumesnapshotclasses/volumesnapshots/configmap
      get/list/watch

      Permission Definition

      kind: ClusterRole
      apiVersion: rbac.authorization.k8s.io/v1
      metadata:
        name: cbs-csi-controller-role
      rules:
        - apiGroups: [""]
          resources: ["pods"]
          verbs: ["get", "list", "watch"]
        - apiGroups: [""]
          resources: ["persistentvolumes"]
          verbs: ["get", "list", "watch", "update", "patch", "create", "delete"]
        - apiGroups: [""]
          resources: ["persistentvolumeclaims"]
          verbs: ["get", "list", "watch", "update"]
        - apiGroups: [""]
          resources: ["persistentvolumeclaims/status"]
          verbs: ["update", "patch"]
        - apiGroups: ["storage.k8s.io"]
          resources: ["storageclasses"]
          verbs: ["get", "list", "watch"]
        - apiGroups: [""]
          resources: ["events"]
          verbs: ["get", "list", "watch", "create", "update", "patch"]
        - apiGroups: ["storage.k8s.io"]
          resources: ["csinodes"]
          verbs: ["get", "list", "watch"]
        - apiGroups: [""]
          resources: ["nodes"]
          verbs: ["get", "list", "watch"]
        - apiGroups: ["coordination.k8s.io"]
          resources: ["leases"]
          verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]
        - apiGroups: ["csi.storage.k8s.io"]
          resources: ["csinodeinfos"]
          verbs: ["get", "list", "watch"]
        - apiGroups: ["storage.k8s.io"]
          resources: ["volumeattachments", "volumeattachments/status"]
          verbs: ["get", "list", "watch", "update", "patch"]
        - apiGroups: ["snapshot.storage.k8s.io"]
          resources: ["volumesnapshotclasses"]
          verbs: ["get", "list", "watch"]
        - 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"]
        - apiGroups: ["apiextensions.k8s.io"]
          resources: ["customresourcedefinitions"]
          verbs: ["create", "list", "watch", "delete"]
        - apiGroups: ["snapshot.storage.k8s.io"]
          resources: ["volumesnapshotcontents/status"]
          verbs: ["update"]
        - apiGroups: ["snapshot.storage.k8s.io"]
          resources: ["volumesnapshots/status"]
          verbs: ["update"]
        - apiGroups: [""]
          resources: ["configmaps"]
          verbs: ["get", "list", "watch", "update", "patch", "create", "delete"]
      ---
      kind: ClusterRole
      apiVersion: rbac.authorization.k8s.io/v1
      metadata:
        name: cbs-csi-node-role
        namespace: kube-system
      rules:
        - apiGroups: [""]
          resources: ["nodes"]
          verbs: ["get", "list"]

      Use Cases

      Avoid attaching cloud disk across availability zones through cbs-csi
      Online Expansion of Cloud Disk
      Creating Snapshot and Using It to Restore Volume
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