Creating a Deployment Mounted with an EVS Volume¶

Scenario¶

After an EVS volume is created or imported to CCE, you can mount it to a workload.

Important

EVS disks cannot be attached across AZs. Before mounting a volume, you can run the kubectl get pvc command to query the available PVCs in the AZ where the current cluster is located.

Prerequisites¶

You have created a cluster and installed the CSI plug-in (everest) in the cluster.

Notes and Constraints¶

The following configuration example applies to clusters of Kubernetes 1.15 or later.

Using EVS Volumes for Deployments¶

Use kubectl to connect to the cluster. For details, see Connecting to a Cluster Using kubectl.

Run the following commands to configure the evs-deployment-example.yaml file, which is used to create a Deployment.

touch evs-deployment-example.yaml

vi evs-deployment-example.yaml

Example of mounting an EVS volume to a Deployment (PVC-based, shared volume):

apiVersion: apps/v1
kind: Deployment
metadata:
  name: evs-deployment-example
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: evs-deployment-example
  template:
    metadata:
      labels:
        app: evs-deployment-example
    spec:
      containers:
      - image: nginx
        name: container-0
        volumeMounts:
        - mountPath: /tmp
          name: pvc-evs-example
      imagePullSecrets:
        - name: default-secret
      restartPolicy: Always
      volumes:
      - name: pvc-evs-example
        persistentVolumeClaim:
          claimName: pvc-evs-auto-example

**Table 1** Key parameters¶
Parent Parameter	Parameter	Description
spec.template.spec.containers.volumeMounts	name	Name of the volume mounted to the container.
spec.template.spec.containers.volumeMounts	mountPath	Mount path of the container. In this example, the volume is mounted to the /tmp directory.
spec.template.spec.volumes	name	Name of the volume.
spec.template.spec.volumes.persistentVolumeClaim	claimName	Name of an existing PVC.

Note

spec.template.spec.containers.volumeMounts.name and spec.template.spec.volumes.name must be consistent because they have a mapping relationship.

Run the following command to create the workload:
kubectl create -f evs-deployment-example.yaml

Using EVS Volumes for StatefulSets¶

Use kubectl to connect to the cluster. For details, see Connecting to a Cluster Using kubectl.

Run the following commands to configure the evs-statefulset-example.yaml file, which is used to create a Deployment.

touch evs-statefulset-example.yaml

vi evs-statefulset-example.yaml

Mounting an EVS volume to a StatefulSet (PVC template-based, non-shared volume):

Example YAML:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: evs-statefulset-example
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      app: evs-statefulset-example
  template:
    metadata:
      labels:
        app: evs-statefulset-example
    spec:
      containers:
        - name: container-0
          image: 'nginx:latest'
          volumeMounts:
            - name: pvc-evs-auto-example
              mountPath: /tmp
      restartPolicy: Always
      imagePullSecrets:
        - name: default-secret
  volumeClaimTemplates:
    - metadata:
        name: pvc-evs-auto-example
        namespace: default
        labels:
          failure-domain.beta.kubernetes.io/region: eu-de
          failure-domain.beta.kubernetes.io/zone:
        annotations:
          everest.io/disk-volume-type: SAS
      spec:
        accessModes:
          - ReadWriteOnce
        resources:
          requests:
            storage: 10Gi
        storageClassName: csi-disk
  serviceName: evs-statefulset-example-headless
  updateStrategy:
    type: RollingUpdate

**Table 2** Key parameters¶
Parent Parameter	Parameter	Description
metadata	name	Name of the created workload.
spec.template.spec.containers	image	Image of the workload.
spec.template.spec.containers.volumeMount	mountPath	Mount path of the container. In this example, the volume is mounted to the /tmp directory.
spec	serviceName	Service corresponding to the workload. For details about how to create a Service, see Creating a StatefulSet.

Note

spec.template.spec.containers.volumeMounts.name and spec.volumeClaimTemplates.metadata.name must be consistent because they have a mapping relationship.

Run the following command to create the workload:
kubectl create -f evs-statefulset-example.yaml

Verifying Persistent Storage of an EVS Volume¶

Query the pod and EVS files of the deployed workload (for example, evs-statefulset-example).
1. Run the following command to query the pod name of the workload:
```
kubectl get po | grep evs-statefulset-example
```
  Expected outputs:
```
evs-statefulset-example-0   1/1     Running   0          22h
```
2. Run the following command to check whether an EVS volume is mounted to the /tmp directory:
```
kubectl exec evs-statefulset-example-0 -- df tmp
```
  Expected outputs:
```
/dev/sda        10255636 36888  10202364   1% /tmp
```
Run the following command to create a file named test in the /tmp directory:
```
kubectl exec evs-statefulset-example-0 -- touch /tmp/test
```

Run the following command to view the file in the /tmp directory:

kubectl exec evs-statefulset-example-0 -- ls -l /tmp

Expected outputs:

-rw-r--r-- 1 root root     0 Jun  1 02:50 test

Run the following command to delete the pod named evs-statefulset-example-0:
```
kubectl delete po evs-statefulset-example-0
```
Check whether the file still exists after the pod is rebuilt.
1. Run the following command to query the name of the rebuilt pod:
```
kubectl get po
```
  Expected outputs:
```
evs-statefulset-example-0   1/1     Running   0          2m
```
2. Run the following command to view the file in the /tmp directory:
```
kubectl exec evs-statefulset-example-0 -- ls -l /tmp
```
  Expected outputs:
```
-rw-r--r-- 1 root root     0 Jun  1 02:50 test
```
3. The test file still exists after the pod is rebuilt, indicating that the data in the EVS volume can be persistently stored.

last updated: 2023-12-08 00:45