Expand volume

You can expand the storage volume size of each pod.

NOTE

Volume expansion triggers pod restart, all pods restart in the order of learner -> follower -> leader and the leader pod may change after the operation.

Before you start

Check whether the cluster status is Running. Otherwise, the following operations may fail.

kubectl get cluster mycluster -n demo
>
NAME        CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS    AGE
mycluster   apecloud-mysql       ac-mysql-8.0.30   Delete               Running   27m

kbcli cluster list mycluster -n demo
>
NAME        NAMESPACE   CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS    CREATED-TIME
mycluster   demo        apecloud-mysql       ac-mysql-8.0.30   Delete               Running   Sep 19,2024 16:01 UTC+0800

Steps

Apply an OpsRequest. Change the value of storage according to your need and run the command below to expand the volume of a cluster.

kubectl apply -f - <<EOF
apiVersion: apps.kubeblocks.io/v1alpha1
kind: OpsRequest
metadata:
  name: ops-volume-expansion
  namespace: demo
spec:
  clusterName: mycluster
  type: VolumeExpansion
  volumeExpansion:
  - componentName: mysql
    volumeClaimTemplates:
    - name: data
      storage: "40Gi"
EOF

Validate the volume expansion operation.

kubectl get ops -n demo
>
NAME                              TYPE              CLUSTER     STATUS    PROGRESS   AGE
mycluster-volumeexpansion-8257f   VolumeExpansion   mycluster   Succeed   3/3        4m40s

If an error occurs, you can troubleshoot with kubectl describe ops -n demo command to view the events of this operation.

After the cluster status is Running again, check whether the corresponding cluster resources change.
```
kubectl describe cluster mycluster -n demo
```

Change the value of spec.componentSpecs.volumeClaimTemplates.spec.resources in the cluster YAML file.

spec.componentSpecs.volumeClaimTemplates.spec.resources is the storage resource information of the pod and changing this value triggers the volume expansion of a cluster.

kubectl edit cluster mycluster -n demo

Edit the value of spec.componentSpecs.volumeClaimTemplates.spec.resources.

apiVersion: apps.kubeblocks.io/v1alpha1
kind: Cluster
metadata:
  name: mycluster
  namespace: demo
spec:
  clusterDefinitionRef: apecloud-mysql
  clusterVersionRef: ac-mysql-8.0.30
  componentSpecs:
  - name: mysql
    componentDefRef: mysql
    replicas: 3
    volumeClaimTemplates:
    - name: data
      spec:
        accessModes:
          - ReadWriteOnce
        resources:
          requests:
            storage: 40Gi # Change the volume storage size
  terminationPolicy: Delete

Check whether the corresponding cluster is running and whether resources change.

kubectl get cluster mycluster -n demo

kubectl describe cluster mycluster -n demo

Change configuration.

Configure the values of --components, --volume-claim-templates, and --storage, and run the command below to expand the volume.
```
kbcli cluster volume-expand mycluster --components="mysql" --volume-claim-templates="data" --storage="40Gi" -n demo
```
- --components describes the component name for volume expansion.
- --volume-claim-templates describes the VolumeClaimTemplate names in components.
- --storage describes the volume storage size.
Validate the volume expansion operation.
- View the OpsRequest progress.
  
  KubeBlocks outputs a command automatically for you to view the details of the OpsRequest progress. The output includes the status of this OpsRequest and PVC. When the status is Succeed, this OpsRequest is completed.
```
kbcli cluster describe-ops mycluster-volumeexpansion-8257f -n demo
```
- View the cluster status.
```
kbcli cluster list mycluster -n demo
>
NAME        NAMESPACE   CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS     CREATED-TIME
mycluster   demo        apecloud-mysql       ac-mysql-8.0.30   Delete               Updating   Sep 19,2024 16:01 UTC+0800
```
  - STATUS=Updating: it means the volume expansion is in progress.
  - STATUS=Running: it means the volume expansion operation has been applied.
After the OpsRequest status is Succeed or the cluster status is Running again, check whether the corresponding resources change.
```
kbcli cluster describe mycluster -n demo
```