If you specify FlexVolume as the volume plug-in for a Container Service for Kubernetes (ACK) cluster that runs Kubernetes earlier than 1.16, the system installs FlexVolume and Disk Controller in the cluster by default. However, the system does not automatically install NAS Controller. This topic describes how to install and upgrade FlexVolume and how to install NAS Controller.

Prerequisites

Limits

Only CentOS 7 and Aliyun Linux 2 are supported.

Install the components

Install FlexVolume

  • Clusters that run Kubernetes 1.16 and later do not support FlexVolume. You must install CSI-Plugin in these clusters. For more information, see Differences between the CSI and FlexVolume plug-ins.
  • If you specify FlexVolume as the volume plug-in for an ACK cluster that runs Kubernetes earlier than 1.16, the system installs FlexVolume in the cluster by default. For more information, see Component configurations.

Install Disk Controller

  • Clusters that run Kubernetes 1.16 and later do not support Disk Controller. You must install CSI-Provisioner in these clusters. For more information, see Differences between the CSI and FlexVolume plug-ins.
  • If you specify FlexVolume as the volume plug-in for an ACK cluster that runs Kubernetes earlier than 1.16, the system installs Disk Controller in the cluster by default. For more information, see Component configurations.

Install NAS Controller

If your cluster already has FlexVolume installed, you can manually install NAS Controller and then dynamically provision volumes that use Apsara File Storage NAS (NAS) file systems.

You can use the following YAML template to manually install NAS Controller: 
kind: Deployment
apiVersion: apps/v1
metadata:
  name: alicloud-nas-controller
  namespace: kube-system
spec:
  selector:
    matchLabels:
      app: alicloud-nas-controller
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: alicloud-nas-controller
    spec:
      tolerations:
      - operator: Exists
      affinity:
        nodeAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 1
            preference:
              matchExpressions:
              - key: node-role.kubernetes.io/master
                operator: Exists
      priorityClassName: system-node-critical
      serviceAccount: admin
      hostNetwork: true
      containers:
        - name: nfs-provisioner
          image: registry.cn-hangzhou.aliyuncs.com/acs/alicloud-nas-controller:v1.14.3.8-58bf821-aliyun
          env:
          - name: PROVISIONER_NAME
            value: alicloud/nas
          securityContext:
            privileged: true
          volumeMounts:
          - mountPath: /var/log
            name: log
      volumes:
      - hostPath:
          path: /var/log
        name: log

Verify the installation

Check whether FlexVolume, Disk Controller, and NAS Controller are installed in the cluster.

  • Run the following command to check whether FlexVolume is installed in the cluster: 
    kubectl get pod -nkube-system | grep flexvolume
  • Run the following command to check whether Disk Controller is installed in the cluster: 
    kubectl get pod -nkube-system | grep alicloud-disk-controller
  • Run the following command to check whether NAS Controller is installed in the cluster: 
    kubectl get pod -nkube-system | grep alicloud-nas-controller

Upgrade the components

You can upgrade FlexVolume and Disk Controller in the ACK console. You cannot upgrade NAS Controller in the ACK console.

If your ACK cluster is upgraded to Kubernetes 1.16 or later, the cluster still supports FlexVolume. You can upgrade FlexVolume in the ACK console.

  1. Log on to the ACK console.
  2. In the left-side navigation pane of the ACK console, click Clusters.
  3. On the Clusters page, find the cluster that you want to manage and click the name of the cluster or click Details in the Actions column. The details page of the cluster appears.
  4. In the left-side navigation pane of the details page, choose Operations > Add-ons.
  5. Click the Storage tab, find flexvolume and alicloud-disk-controller, and then click Upgrade.
  6. In the Note message, confirm the versions of the plug-ins and click OK.
    After the plug-ins are upgraded, the system prompts that the upgrades are completed and the current versions of the plug-ins are displayed.
  • When you upgrade FlexVolume in the following scenarios, Submit a ticket to request technical support.
    • The system fails to update FlexVolume in the ACK console.
    • The version of FlexVolume is 1.12 or earlier, and volumes that use disks and Object Storage Service (OSS) buckets are provisioned in the cluster.
    • You want to ensure a successful upgrade because sensitive business data is stored in the cluster and a large number of volumes are used.
  • The system fails to upgrade Disk Controller. In this case, Submit a ticket to request technical support.