Support data persistent: integrate with storageClass

[ahrtr]

The goal is to ensure the etcd's data will not get lost once the VM or POD is rebooted.

So we need to support setting VolumeClaimTemplate for the statefulset, something like below,

  volumeClaimTemplates:
  - metadata:
      name: etcd-data
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: "csi-sc-standard"
      resources:
        requests:
          storage: 32Gi

Note that it isn't etcd-operator's responsibility to provision / manage the CSI driver in production environment.

But we need to provision / manage a CSI driver for our test environment,

• one possible solution that I can think of is openebs localpv.

• or csi-driver-host-path for single node test environment.

• or use hostPath directly, something like below,

   volumes:
   - name: my-data
     hostPath:
       path: /data/${POD_NAME}
       type: DirectoryOrCreate
  

I am open to other alternatives.

[ahrtr]

This isn't a good first issue. It needs some experience on K8s and PV/PVC/StorageClass.

[liangyuanpeng]

But we need to provision / manage a CSI driver for our test environment,

etcd-operator is using Kind for CI, and Kind including a local path provider, so i think just use local-path provider from Kind is enough?

$ k get sc
NAME                 PROVISIONER             RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
standard (default)   rancher.io/local-path   Delete          WaitForFirstConsumer   false                  15m

[ahrtr]

/assign @gdasson

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/assign @gdasson

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