Container Service for Kubernetes:Use a dynamically provisioned disk volume

Use a dynamically provisioned disk volume in the ACK console

Step 1: Create a StorageClass

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

2. On the Clusters page, click the name of the cluster that you want to manage and choose Volumes > StorageClasses in the left-side navigation pane.

3. In the upper-right corner of the StorageClasses page, click Create.

4. In the Create dialog box, configure the parameters.

   The following table describes the parameters.

   Parameter	Description
   Name	The name of the StorageClass. The name must start with a lowercase letter and can contain only lowercase letters, digits, periods (.), and hyphens (-).
   PV Type	The type of the persistent volume (PV). Select Cloud Disk.
   Parameter	By default, the type parameter is added and set to cloud_essd. The type parameter specifies the disk types. Valid values: cloud_efficiency, cloud_ssd, cloud_essd, and available. You can specify one or more values. However, if you specify available, you cannot specify other values. For example, if you specify type: cloud_efficiency, cloud_ssd, cloud_essd, the system attempts to create a disk of the specified types in sequence. The system stops trying if a disk is created. If you set the parameter to available, the system first attempts to create a standard SSD. If the attempt fails, the system attempts to create an ultra disk. The system stops trying if a disk is created. Note Some ECS instance types do not support Enterprise SSDs (ESSDs). For more information, see FAQ. You can add custom parameters. For example, you can add the zoneId parameter to specify the IDs of the zones in which you want to create the disk. If your cluster is deployed in a single zone, set the value to the ID of the zone. Example: cn-beijing-a. If your cluster is deployed across zones, you can set the zoneId parameter to multiple zone IDs based on your business requirements. Example: cn-beijing-a, cn-beijing-b.
   Reclaim Policy	The reclaim policy of the disk. By default, this parameter is set to Delete. You can also set this parameter to Retain. Delete mode: When persistent volume claims (PVCs) are deleted, the related PVs and disks are also deleted. Retain mode: When PVCs are deleted, the related PVs and disks are retained. The PVs and disk data can only be manually deleted. If you require higher data security, we recommend that you use the Retain mode to prevent data from being accidentally deleted.
   Binding Mode	The mount mode of the disk. Default value: Immediate, which specifies that the system creates a disk before it creates a pod.

5. After you configure the parameters, click Create.

   You can find the created StorageClass in the StorageClasses list.

Step 2: Create a PVC

1. In the left-side navigation pane of the details page, choose Volumes > Persistent Volume Claims.

2. In the upper-right corner of the Persistent Volume Claims page, click Create.

3. In the Create PVC dialog box, configure the parameters that are described in the following table.

   Parameter	Description
   PVC Type	The type of the PVC. You can set this parameter to Cloud Disk or NAS. In this example, this parameter is set to Cloud Disk.
   Name	The name of the PVC. The name must be unique in the namespace.
   Allocation Mode	In this example, Use StorageClass is selected.
   Existing Storage Class	Click Select. In the Select Storage Class dialog box, find the StorageClass that you want to use and click Select in the Actions column.
   Capacity	The capacity claimed by the PVC.
   Access mode	The access mode of the PV. By default, this parameter is set to ReadWriteOnce.

4. Click Create.

   After the PVC is created, you can view the PVC in the PVC list. The PVC is bound to a PV.

Step 3: Create an application

1. In the left-side navigation pane of the details page, choose Workloads > StatefulSets.

2. In the upper-right corner of the StatefulSets page, click Create from Image.

3. Configure the application parameters.
   This example shows how to configure the volume parameters. For more information about other parameters, see Use a StatefulSet to create a stateful application.

   You can configure local storage volumes and cloud storage volumes for an ACK cluster. In this example, Cloud Storage is selected.

   Mount the disk volume that is created in this example to the /tmp path of the container. After the disk volume is mounted, the container data that is generated in the /tmp path is stored in the disk volume.
4. Configure other parameters and click Create.
   After the application is created, you can use the volume to store application data.

Use a dynamically provisioned disk volume by using kubectl

Step 1: Create a StorageClass

In a multi-zone cluster, you can create a StorageClass by first creating a cloud disk and then creating a pod.

1. Use the following template to create a file named storage-class-csi.yaml:

   apiVersion: storage.k8s.io/v1
   kind: StorageClass
   metadata:
     name: alicloud-disk-ssd-b
   provisioner: diskplugin.csi.alibabacloud.com
   parameters:
     type: cloud_ssd
     encrypted: "false"
   reclaimPolicy: Retain
   allowVolumeExpansion: true
   volumeBindingMode: Immediate

   Parameter	Description
   provisioner	Set the value to diskplugin.csi.alibabacloud.com. This specifies that the provisioner plug-in for Alibaba Cloud disks is used to create the StorageClass.
   type	The type of disk. Valid values: cloud_efficiency, cloud_ssd, cloud_essd, and available. You can specify one or more values. However, if you specify available, you cannot specify other values. For example, if you specify type: cloud_efficiency, cloud_ssd, cloud_essd, the system attempts to create a disk of the specified types in sequence. The system stops creating disks until a disk is created. If you set this parameter to available, the system first attempts to create a standard SSD. If the attempt fails, the system attempts to create an ultra disk. The system stops creating disks until a disk is created. Note Some ECS instance types do not support ESSDs. For more information, see FAQ.
   encrypted	Optional. This parameter specifies whether the disk is encrypted. The default value is false, which indicates that the disk is not encrypted.
   reclaimPolicy	The reclaim policy of the disk. By default, this parameter is set to Delete. You can also set this parameter to Retain. Delete mode: When PVCs are deleted, the related PVs and disks are also deleted. Retain mode: When PVCs are deleted, the related PVs and disks are retained. The PVs and disk data can only be manually deleted. If you require high data security, we recommend that you use the Retain mode to prevent data from being accidentally deleted.
   allowVolumeExpansion	If you set this parameter to true, the disk can be automatically expanded.
   volumeBindingMode	The mount mode of the disk. Default value: Immediate, which specifies that the system creates a disk before it creates a pod.

2. Run the following command to create a StorageClass:

   kubectl apply -f storage-class-csi.yaml

3. View the created StorageClass.

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

   2. On the Clusters page, click the name of the cluster that you want to manage and choose Volumes > StorageClasses in the left-side navigation pane.

   3. You can view the created StorageClass on the StorageClasses page.

Step 2: Create a PVC

1. Use the following template to create a file named pvc-ssd.yaml:

   apiVersion: v1
   kind: PersistentVolumeClaim
   metadata:
     name: disk-pvc
   spec:
     accessModes:
     - ReadWriteOnce
     volumeMode: Filesystem
     resources:
       requests:
         storage: 25Gi
     storageClassName: alicloud-disk-ssd-b

   Parameter	Description
   name	The name of the PVC.
   accessModes	The access mode of the PV.
   volumeMode	Optional. The format in which the disk is mounted. File systems are supported.
   storageClassName	The name of the StorageClass that you want to associate with the PVC.
   storage	The disk size claimed by the PVC. The minimum capacity is 20 GiB.

2. Run the following command to create a PVC:

   kubectl create -f pvc-ssd.yaml

3. View the created PVC.

   In the left-side navigation pane of the cluster details page, choose Volumes > Persistent Volume Claims. You can view the created PVC on the Persistent Volume Claims page.

Step 3: Create an application

1. Create a file named pvc-dynamic.yaml.

   Use the following template to create an application named nginx-dynamic and mount the PVC to the application:

   apiVersion: apps/v1
   kind: StatefulSet
   metadata:
     name: nginx-dynamic
   spec:
     selector:
       matchLabels:
         app: nginx
     template:
       metadata:
         labels:
           app: nginx
       spec:
         containers:
         - name: nginx
           image: nginx
           ports:
           - containerPort: 80
             name: web
           volumeMounts:
           - name: pvc-disk
             mountPath: /data
         volumes:
           - name: pvc-disk
             persistentVolumeClaim:
               claimName: disk-pvc

   Parameter	Description
   mountPath	The path to which the disk is mounted.
   claimName	The name of the PVC that is mounted to the application.

2. Run the following command to deploy the application and mount the PVC to the application:

   kubectl create -f pvc-dynamic.yaml

3. View the deployed application.

   In the left-side navigation pane of the details page, choose Workloads > StatefulSets. You can find the created application on the StatefulSets page.