Container Service for Kubernetes:Use LVM to dynamically create local volumes

Step 1: Install the node-resource-manager, csi-plugin, and csi-provisioner add-ons

These add-ons provide Container Storage Interface (CSI) support for local LVM volumes. Install all three before using LVM to manage local storage.

1. Log on to the ACK console. In the left navigation pane, click Clusters.

2. On the Clusters page, click the target cluster name and choose Operations > Add-ons in the left-side navigation pane.

3. On the Add-ons page, click the Storage tab. Find node-resource-manager, csi-plugin, and csi-provisioner, and click Install.

4. In the dialog box, click OK.

Step 2: Configure the VolumeGroup

A VolumeGroup specifies which local disks LVM manages on a node. Create a ConfigMap to map node labels to disk topologies. The VolumeGroup in prose corresponds to the volumegroup field in the ConfigMap YAML.

1. Configure the VolumeGroup topology with the following ConfigMap:

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: node-resource-topo
     namespace: kube-system
   data:
     volumegroup: |-
       volumegroup:
       - name: volumegroup1
         key: kubernetes.io/storagetype
         operator: In
         value: lvm
         topology:
           type: device
           devices:
           - /dev/sdb1
           - /dev/sdb2
           - /dev/sdc

   The following table describes the parameters.

   Parameter	Description
   name	The name of the VolumeGroup.
   key	The label key to match on nodes.
   operator	The label selector operator. Valid values: In, NotIn, Exists, DoesNotExist. See the operator values table below.
   value	The label value to match for the specified key.
   topology	The device topology on the node. topology.devices lists the local disk paths to add to the VolumeGroup.

   Operator values

   Value	Behavior
   In	Matches when the node label value equals the specified value.
   NotIn	Matches when the node label value differs from the specified value.
   Exists	Matches when the node has a label with the specified key.
   DoesNotExist	Matches when the node lacks a label with the specified key.

2. Add labels to the nodes.

   Add the following labels to storage nodes:

   • Custom topology label: Label storage nodes to match the ConfigMap selector. Example: kubernetes.io/storagetype=lvm.

   • Local storage enablement label: Add alibabacloud.com/edge-enable-localstorage='true' to enable local storage pod scheduling on the node.

   After you add both labels, node-resource-manager automatically creates a physical volume and adds it to the VolumeGroup.

Step 3: Create a PVC and deploy a workload

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: lvm-pvc-test
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 50Mi
  storageClassName: csi-local-lvm

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    k8s-app: local-test
  name: local-test
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      k8s-app: local-test
  template:
    metadata:
      labels:
        k8s-app: local-test
    spec:
      hostNetwork: true
      containers:
      - image: nginx:1.15.7-alpine
        imagePullPolicy: IfNotPresent
        name: nginx
        resources: {}
        volumeMounts:
          - name: local-pvc
            mountPath: /data
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      tolerations:
      - operator: Exists
      nodeSelector:
        alibabacloud.com/is-edge-worker: "true"
      volumes:
      - name: local-pvc
        persistentVolumeClaim:
          claimName: lvm-pvc-test

Verify the result

Check whether the logical volume is mounted:

kubectl exec -it local-test-564dfcf6dc-qhfsf sh
/ # ls /data

Expected output:

lost+found

This confirms the logical volume is mounted to the pod.