Container Service for Kubernetes:Mount a dynamically provisioned NAS volume

Use kubectl

1. Create a StorageClass

1. Create a file named alicloud-nas-subpath.yaml, copy the following content to the file, and then modify the parameters based on your business requirements:

   allowVolumeExpansion: true
   apiVersion: storage.k8s.io/v1
   kind: StorageClass
   metadata:
     name: alicloud-nas-subpath
   mountOptions:
   - nolock,tcp,noresvport
   - vers=3
   parameters:
     volumeAs: subpath
     server: "0cd8b4a576-g****.cn-hangzhou.nas.aliyuncs.com:/k8s/"
   provisioner: nasplugin.csi.alibabacloud.com
   reclaimPolicy: Retain

   Parameter	Description
   allowVolumeExpansion	This parameter is available only for General-purpose NAS file systems. If you set this parameter to true, a NAS directory quota is configured for the dynamically provisioned PV based on the StorageClass. You can modify the PVC to expand the volume. Note The NAS directory quota takes effect in an asynchronous manner. After a PV is dynamically provisioned, the directory quota does not immediately take effect, and the quota may be exceeded if a large amount of data is written within a short period of time. For more information about NAS directory quotas, see Manage directory quotas.
   mountOptions	Set the options of the NAS file system in the mountOptions field. For example, you can specify the NFS version that you want to use.
   volumeAs	Set to subpath. Valid values: subpath: mounts a subdirectory of the NAS file system as a PV. You must manually create a NAS file system and a mount target. A PV corresponds to a subdirectory of a NAS file system. sharepath: No directory is created when the PV is created, but the specified path in the StorageClass is used. This means that each PV corresponds to the same NAS directory, which is suitable for scenarios in which directories are shared across namespaces. filesystem: The provisioner automatically creates a NAS file system. Each PV corresponds to a NAS file system.
   server	The mount target of the NAS file system if you mount a subdirectory of the NAS file system as a PV. If you leave this parameter empty, / is used by default. Important You must specify the actual mount target. For more information about how to query the domain name of a mount target, see Manage mount targets.
   provisioner	The type of driver. In this example, the parameter is set to nasplugin.csi.alibabacloud.com. This indicates that the NAS CSI plug-in provided by Alibaba Cloud is used.
   reclaimPolicy	The reclaim policy of the PV. Default value: Delete. You can also set the value to Retain. Delete: If you use this policy, you must also specify the archiveOnDelete parameter. If you set the archiveOnDelete parameter to true, after you delete the PVC, the files in PV and NAS file system associated with the PVC are renamed and retained. If you set the archiveOnDelete parameter to false, after you delete the PVC, the files in PV and NAS file system associated with the PVC are deleted. Note Only the NAS subpath directories and the files within them are deleted. To delete the NAS file system, see Delete a file system. Retain: When a PVC is deleted, the files in the associated PV and NAS file system are retained and can only be manually deleted. If you have high requirements on data security, we recommend that you use the Retain policy to prevent data loss caused by user errors.
   archiveOnDelete	Specifies whether to delete the files in the backend storage if the reclaimPolicy parameter is set to Delete. NAS is a shared storage service. You must specify both reclaimPolicy and archiveOnDelete parameters to ensure data security. Configure the policy in the parameters section. Default value: true, which indicates that the subdirectory or files are not deleted when the PVC is deleted. Instead, the subdirectory or files are renamed in the format of archived-{pvName}.{timestamp}. If this parameter is set to false, the backend storage is deleted when the PVC is deleted. Note We recommend that you do not set this parameter to false when the service receives a large amount of network traffic. For more information, see What do I do if the task queue of alicloud-nas-controller is full and PVs cannot be created when I use a dynamically provisioned NAS volume? To completely delete the file data from the backend storage, you must add parameters.archiveOnDelete and set it to false using the kubectl method.

2. Run the following command to create a StorageClass:

   kubectl create -f alicloud-nas-subpath.yaml

2. Create a PVC

1. Create a file named pvc.yaml, copy the following content to the file, and then modify the parameters based on your business requirements:

   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata: 
     name: nas-csi-pvc
   spec:
     accessModes:
     - ReadWriteMany 
     storageClassName: alicloud-nas-subpath
     resources: 
       requests:
         storage: 20Gi

   Parameter	Description
   name	The name of the PVC.
   accessModes	The access mode of the PV. The default value is ReadWriteMany. You can also set the value to ReadWriteOnce or ReadOnlyMany.
   storageClassName	The name of the StorageClass that you want to associate with the PVC.
   storage	The storage that is claimed by the PVC. Important The capacity set in this parameter does not limit the actual capacity that applications can use, and does not allow automatic scaling. The quota of a NAS directory is set only if the NAS file system is general-purpose and the allowVolumeExpansion parameter of the StorageClass is set to true. For more information, see Expand a NAS volume. Once the quota of a directory takes effect, CSI will set the quota of a NAS directory based on the PVC capacity. The NAS directory quota is measured in GiB, and the actual quota is calculated by rounding up the PVC capacity to the nearest integer in GiB.

2. Create a PVC.

   kubectl create -f pvc.yaml

3. Create an application and mount the NAS file system to the application

Deploy two applications named nginx-1 and nginx-2 to share the same subdirectory of the NAS file system.

1. Create a file named nginx-1.yaml and copy the following content to the file:

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: deployment-nas-1
     labels:
       app: nginx-1
   spec:
     selector:
       matchLabels:
         app: nginx-1
     template:
       metadata:
         labels:
           app: nginx-1
       spec:
         containers:
         - name: nginx
           image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
           ports:
           - containerPort: 80
           volumeMounts:
             - name: nas-pvc
               mountPath: "/data"
         volumes:
           - name: nas-pvc
             persistentVolumeClaim:
               claimName: nas-csi-pvc

   • mountPath: the path to which the NAS file system is mounted in the container.

   • claimName: the name of the PVC that the application uses to mount the NAS file system. In this example, nas-csi-pvc is used.

2. Create a file named nginx-2.yaml and copy the following content to the file:

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: deployment-nas-2
     labels:
       app: nginx-2
   spec:
     selector:
       matchLabels:
         app: nginx-2
     template:
       metadata:
         labels:
           app: nginx-2
       spec:
         containers:
         - name: nginx
           image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
           ports:
           - containerPort: 80
           volumeMounts:
             - name: nas-pvc
               mountPath: "/data"
         volumes:
           - name: nas-pvc
             persistentVolumeClaim:
               claimName: nas-csi-pvc

   • mountPath: the path to which the NAS file system is mounted in the container. In this example, /data is used.

   • claimName: Enter the name of the PVC that is used by nginx-1. In this example, the value is set to nas-csi-pvc.

3. Deploy the nginx-1 and nginx-2 applications.

   kubectl create -f nginx-1.yaml -f nginx-2.yaml

4. View the pod information.

   kubectl get pod

   Expected output:

   NAME                                READY   STATUS    RESTARTS   AGE
   deployment-nas-1-5b5cdb85f6-a****   1/1     Running   0          32s
   deployment-nas-2-c5bb4746c-b****    1/1     Running   0          32s

   The /data subdirectory of the NAS file system is mounted to different pods. The NAS volume whose mount target is 0cd8b4a576-g****.cn-hangzhou.nas.aliyuncs.com:/k8s/nas-79438493-f3e0-11e9-bbe5-00163e09**** is mounted to the /data directory of the deployment-nas-1-5b5cdb85f6-a**** and deployment-nas-2-c5bb4746c-b**** applications.

   • /k8s: the subdirectory is mounted in subpath mode as specified in the StorageClass configurations.

   • nas-79438493-f3e0-11e9-bbe5-00163e09****: the name of the automatically created PV.

   Note

   To mount different subdirectories of a NAS file system to different pods, you must create a separate PVC for each pod. In this example, pvc-1 is created for nginx-1 and pvc-2 is created for nginx-2.

Use the ACK console

1. Create a StorageClass

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

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

3. On the StorageClasses page, click Create.

4. In the Create dialog box, configure the StorageClass, and click Create.

   The following table describes the parameters.

   Parameter	Description	Example
   Name	The name of the StorageClass. The name must start with a lowercase letter, and can contain only lowercase letters, digits, periods (.), and hyphens (-).	alicloud-nas-subpath
   PV Type	Select NAS.	NAS
   Select Mount Target	The mount target of the NAS file system. For more information about how to query the domain name of a mount target, see Manage mount targets. If no mount target is available, create a NAS file system first. For more information, see Create a NAS file system and a mount target.	0cd8b4a576-g****.cn-hangzhou.nas.aliyuncs.com:/k8s/
   Volume Mode	The access mode of the volume. Shared Directory is selected by default. Valid values: Shared Directory: The NAS volume is mounted in sharepath mode. All volumes share the same path. This means that data is stored at <bucket>:<path>/. Subdirectory: The NAS volume is mounted in subpath mode. When you create a volume, a subdirectory is automatically created in the mount path. This means that data is stored at <bucket>:<path>/<pv-name>/. Note The Subdirectory mode takes effect only if the version of the CSI plug-in is 1.31.4 or later. Otherwise, the Shared Directory mode is used.	Subdirectory
   Mount Path	The mount path of the NAS file system. If the specified subdirectory does not exist, the system automatically creates the subdirectory in the NAS file system and mounts the subdirectory to the cluster. If you do not configure this parameter, the root directory of the NAS file system is mounted. If you want to mount an Extreme NAS file system, set this parameter to a subdirectory of the /share directory. Example: /share/data.	/
   Reclaim Policy	The reclaim policy. Valid values: Delete and Retain. Default value: Delete. Note Parameters such as archiveOnDelete cannot be configured through the console. Therefore, files in backend NAS storage cannot be completely deleted. To delete them completely, use the kubectl method. Delete: If you use this policy, you must configure the archiveOnDelete parameter. If you set the archiveOnDelete parameter to true, files in the PV and NAS file system associated with a PVC are renamed and retained after you delete the PVC. If you set the archiveOnDelete parameter to false, files in the PV and NAS file system associated with a PVC are deleted after you delete the PVC. Retain: If a PVC is deleted, files in the related PV and NAS file system are retained and can only be manually deleted. If you have high requirements for data security, we recommend that you use the Retain policy to prevent data loss caused by user errors.	Retain
   Mount Options	The mount options, such as the Network File System (NFS) version. We recommend that you use NFS v3. Extreme NAS file systems support only NFS v3 For more information about the NFS protocol, see NFS.	Retain the default setting.

   After you create the StorageClass, you can view the StorageClass on the StorageClasses page.

2. Create a PVC

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

2. On the Persistent Volume Claims page, click Create.

3. In the Create PVC dialog box, configure the parameters and click Create.

   Parameter	Description	Example
   PVC Type	Select NAS.	NAS
   Name	The name of the PVC. The name must be unique in the cluster.	pvc-nas
   Allocation Mode	Select Use StorageClass.	Use StorageClass
   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.	Select the alicloud-nas-subpath StorageClass created in the previous step.
   Capacity	The capacity claimed by the PVC. The value of this parameter does not specify a limit for the maximum capacity that can be used by the application. Important The capacity set in this parameter does not limit the actual capacity that applications can use, and does not allow automatic scaling. The quota of a NAS directory is set only if the NAS file system is general-purpose and the allowVolumeExpansion parameter of the StorageClass is set to true. For more information, see Expand a NAS volume. Once the quota of a directory takes effect, CSI will set the quota of a NAS directory based on the PVC capacity. The NAS directory quota is measured in GiB, and the actual quota is calculated by rounding up the PVC capacity to the nearest integer in GiB.	20Gi
   Access Mode	Default value: ReadWriteMany. You can also set the value to ReadWriteOnce or ReadOnlyMany.	ReadWriteMany

3. Create an application and mount the NAS file system to the application

To create the applications named deployment-nas-1 and deployment-nas-2, perform the following operations. Make sure that the applications share the same subdirectory of the NAS file system.

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

2. On the Deployments tab, click Create from Image.

3. Configure the application parameters.

   The following table describes the key parameters. Use the default settings for other parameters. For more information, see Create a stateless application by using a Deployment.

   Item	Parameter	Description	Example
   Basic Information	Name	Enter a custom name for the Deployment. The name must follow the format requirements displayed in the console.	deployment-nas-1
   	Replicas	The number of replicas for the Deployment.	2
   Container	Image Name	The address of the image used to deploy the application.	anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
   	Required Resources	The required vCPU and memory resources.	0.25 vCores and 512 MiB of memory
   	Volume	Click Add PVC and configure the parameters. Mount Source: Select the PVC you created. Container Path: Specify the container path to which you want to mount the NAS file system.	Mount Source: pvc-nas Container Path: /data

4. Run the following command to query the deployment progress of the application:

   1. On the Deployments page, click the name of the application that you want to manage.

   2. On the Pods tab, check whether the pod is in the Running state.

Use kubectl

1. Create a StorageClass

1. Create a file named alicloud-nas-subpath.yaml, copy the following content to the file, and modify the parameters based on your business requirements:

   apiVersion: storage.k8s.io/v1
   kind: StorageClass
   metadata:
     name: alicloud-nas-sharepath
   mountOptions:
   - nolock,tcp,noresvport
   - vers=3
   parameters:
     volumeAs: sharepath
     server: "0cd8b4a576-g****.cn-hangzhou.nas.aliyuncs.com:/data"
   provisioner: nasplugin.csi.alibabacloud.com
   reclaimPolicy: Retain

   Parameter	Description
   mountOptions	The mount options, such as the Network File System (NFS) version. We recommend that you use NFS v3. Extreme NAS file systems support only NFS v3 For more information about the NFS protocol, see NFS.
   volumeAs	Set to sharepath. Valid values: subpath: mounts a subdirectory of the NAS file system as a PV. You must manually create a NAS file system and a mount target. A PV corresponds to a subdirectory of a NAS file system. sharepath: No directory is created when the PV is created, but the specified path in the StorageClass is used. This means that each PV corresponds to the same NAS directory, which is suitable for scenarios in which directories are shared across namespaces. filesystem: The provisioner automatically creates a NAS file system. Each PV corresponds to a NAS file system.
   server	The mount target and mount path of the NAS file system if you mount a subdirectory of the NAS file system as a PV. If you do not configure the mount path, / is used by default. Important You must specify the actual mount target. For more information about how to view the domain name of a mount target, see Manage mount targets.
   provisioner	The type of driver. In this example, the parameter is set tonasplugin.csi.alibabacloud.com. This indicates that the CSI plug-in provided by Alibaba Cloud for NAS is used.
   reclaimPolicy	You must select Retain if you use the sharepath mode.

2. Create a StorageClass.

   kubectl create -f alicloud-nas-sharepath.yaml

2. Create PVCs in different namespaces

To mount a NAS file system to pods in different namespaces, you must create two namespaces.

1. Run the following command to create namespaces named ns1 and ns2:

   kubectl create ns ns1
   kubectl create ns ns2

2. Create a file named pvc.yaml, copy the following content to the file, and then modify the parameters based on your business requirements:

   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata: 
     name: nas-csi-pvc
     namespace: ns1
   spec:
     accessModes:
     - ReadWriteMany 
     storageClassName: alicloud-nas-sharepath
     resources: 
       requests:
         storage: 20Gi
   ---
   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata: 
     name: nas-csi-pvc
     namespace: ns2
   spec:
     accessModes:
     - ReadWriteMany 
     storageClassName: alicloud-nas-sharepath
     resources: 
       requests:
         storage: 20Gi

   Parameter	Description
   name	The name of the PVC.
   accessModes	The access mode of the PV. The default value is ReadWriteMany. You can also set the value to ReadWriteOnce or ReadOnlyMany.
   storageClassName	The name of the StorageClass that you want to associate with the PVC.
   storage	The storage that is claimed by the PVC. Important If you use the sharepath mode, this parameter does not take effect.

3. Create a PVC.

   kubectl create -f pvc.yaml

3. Create an application and mount the NAS file system to the application

1. Create applications in different namespaces and mount the PVCs created in the corresponding namespaces. The applications share the NAS volume defined in the StorageClass.

   1. Create a file named nginx.yaml and copy the following content to the file. This file contains two Deployments.

      apiVersion: apps/v1
      kind: Deployment
      metadata:
        name: nginx
        namespace: ns1
      spec:
        selector:
          matchLabels:
            app: nginx
        template:
          metadata:
            labels:
              app: nginx
          spec:
            containers:
            - name: nginx
              image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
              ports:
              - containerPort: 80
              volumeMounts:
                - name: nas-pvc
                  mountPath: "/data"
            volumes:
              - name: nas-pvc
                persistentVolumeClaim:
                  claimName: nas-csi-pvc
      ---
      apiVersion: apps/v1
      kind: Deployment
      metadata:
        name: nginx
        namespace: ns2
      spec:
        selector:
          matchLabels:
            app: nginx
        template:
          metadata:
            labels:
              app: nginx
          spec:
            containers:
            - name: nginx
              image: anolis-registry.cn-zhangjiakou.cr.aliyuncs.com/openanolis/nginx:1.14.1-8.6
              ports:
              - containerPort: 80
              volumeMounts:
                - name: nas-pvc
                  mountPath: "/data"
            volumes:
              - name: nas-pvc
                persistentVolumeClaim:
                  claimName: nas-csi-pvc

      • mountPath: the path to which the NAS file system is mounted in the container.

      • claimName: the name of the PVC that the application uses to mount the NAS file system. In this example, nas-csi-pvc is used.

   2. Create an application.

      kubectl create -f nginx.yaml

2. View the pod information.

   kubectl get pod -A -l app=nginx

   Expected output:

   NAMESPACE  NAME                READY   STATUS    RESTARTS   AGE
   ns1      nginx-5b5cdb85f6-a****   1/1     Running   0          32s
   ns2      nginx-c5bb4746c-b****    1/1     Running   0          32s

   Mount the /data subdirectory of the NAS file system for pods in different namespaces. The NAS volume whose mount target is 0cd8b4a576-g****.cn-hangzhou.nas.aliyuncs.com:/data is mounted to the /data directory of the nginx-5b5cdb85f6-a**** and the nginx-c5bb4746c-b**** applications.

Use the ACK console

Verify that the NAS file system can be used to persist data

1. Run the following command to query the pods that are created for the application:

   kubectl get pod 

   Expected output:

   NAME                                READY   STATUS    RESTARTS   AGE
   deployment-nas-1-5b5cdb85f6-a****   1/1     Running   0          32s
   deployment-nas-2-c5bb4746c-b****    1/1     Running   0          32s

2. Create a file in the pod.

   1. Check whether a file exists in the /data path that is mounted to the application.

      In this example, the pod deployment-nas-1-5b5cdb85f6-a**** is used.

      kubectl exec deployment-nas-1-5b5cdb85f6-a**** -- ls /data

      No output is returned. This indicates that no file exists in the /data path.

   2. Run the following command to create a file named nas in the /data path of the pod:

      kubectl exec deployment-nas-1-5b5cdb85f6-a**** -- touch /data/nas

3. Access the file you created from the other pod.

   In this example, the pod deployment-nas-2-c5bb4746c-b**** is used.

   kubectl exec deployment-nas-2-c5bb4746c-b**** -- ls /data

   Expected output:

   nas

4. Recreate the pod.

   1. Delete the pod.

      kubectl delete pod deployment-nas-1-5b5cdb85f6-a****

   2. Open another command-line interface (CLI) and view how the pod is deleted and recreated:

      kubectl get pod -w -l app=nginx

5. Verify that the file still exists after the pod is deleted.

   1. Query the recreated pod.

      kubectl get pod

      Expected output:

      NAME                                READY   STATUS    RESTARTS   AGE
      deployment-nas-1-5b5cdm2g5-c****    1/1     Running   0          32s
      deployment-nas-2-c5bb4746c-b****    1/1     Running   0          32s

   2. Query files in the /data path of the recreated pod.

      In this example, the pod deployment-nas-1-5b5cdm2g5-c**** is used.

      kubectl exec deployment-nas-1-5b5cdm2g5-c**** -- ls /data

      Expected output:

      nas

      The nas file still exists in the /data path. This indicates that data is persisted in the NAS file system.

Verify that data in the NAS file system can be shared across pods

You can mount a NAS volume to multiple pods. If data is modified in one pod, the modifications are automatically synchronized to the other pods. The following example describes how to verify that data in the NAS file system can be shared across pods.

1. Query the pods that are created for the application and the files in the mounted NAS file system.

   1. Run the following command to query the pods that are created for the application:

      kubectl get pod 

      Expected output:

      NAME                                READY   STATUS    RESTARTS   AGE
      deployment-nas-1-5b5cdb85f6-a****   1/1     Running   0          32s
      deployment-nas-2-c5bb4746c-b****    1/1     Running   0          32s

   2. View the files in the /data paths of the two pods.

      kubectl exec deployment-nas-1-5b5cdb85f6-a**** -- ls /data
      kubectl exec deployment-nas-2-c5bb4746c-b**** -- ls /data

      No output is returned. This indicates that no file exists in the /data path.

2. Create a file named nas in the /data path of a pod.

   In this example, the pod deployment-nas-1-5b5cdb85f6-a**** is used.

    kubectl exec deployment-nas-1-5b5cdb85f6-a**** -- touch /data/nas

3. View the files in the /data paths of the two pods.

   1. Run the following command to query the file in the /data path of the pod deployment-nas-1-5b5cdb85f6-a****:

      kubectl exec deployment-nas-1-5b5cdb85f6-a**** -- ls /data

      Expected output:

      nas

   2. Run the following command to query files in the /data path of the pod deployment-nas-2-c5bb4746c-b****:

      kubectl exec deployment-nas-2-c5bb4746c-b**** -- ls /data

      Expected output:

      nas

      After you create a file in the /data path of one pod, you can also find the file in the /data path of the other pod. This indicates that data in the NAS file system is shared by the two pods.