Docs

Volcengine Kubernetes Engine

NFS access methods

Using static EFS PVs via NFS

This topic describes how to create an EFS PersistentVolume (PV) and PersistentVolumeClaim (PVC) via NFS, and how workloads use a static EFS PV.

Prerequisites

The csi-nas add-on has been installed. For details, see Installing add-ons.

An EFS filesystem and mount point have been created. For details, see Creating an EFS filesystem and Managing mount points.

(Optional) The kubectl tool has already been installed locally, and the target cluster has been connected by using kubectl. For details, see Connecting to clusters.

Usage limits

StatefulSets require exclusive access to a volume, and do not support a manually created PVC.

EFS PVs are only available in some regions. For details, see Regions and availability zones.

Creating through the console

Step 1: Create a PV

In the left navigation pane, click Cluster. In the right part of the page, click the target cluster name to open the management page of this cluster.

In the left navigation bar of the cluster management page, click Storage > PersistentVolume. Click Create PersistentVolume and configure parameters on the page that appears.

Parameter	Description
How to create	Select a method for creating the PV. Currently, you can select Static creation, in which the administrator creates one.
Name	Specify a valid name for the PV. The name must be unique within the cluster.
StorageClass type	Select the storage type. In this scenario, select EFS.
Access type	Select an access type for the PV. Valid values: FSX and NFS. In this scenario, select NFS.
Access mode	Select a PV access mode. You can select ReadWriteMany, which enables read and write access by multiple nodes.
Project	Assign the PV to a project so that you can perform operations such as maintenance and authorization at the project level. By default, the default project is selected. For more details, see Project management.
Mount point	Select a mount point that exists under a created NFS file system and is in the same VPC as the cluster.
Subdirectory	Enter a valid subdirectory that complies with the on-screen rules. The default directory is the root directory, which is represented by /. tip Ensure that the subdirectory already exists in EFS.
NFS version	Select an NFS version for the PV. NFSv3 and NFSv4.1 are supported.

Click Confirm.

Step 2: Create a PVC

In the left navigation bar of the cluster management page, click Storage > PersistentVolumeClaim. Click Create PersistentVolumeClaim and configure parameters on the page that appears.

Parameter	Description
Namespace	Select the namespace to which the PVC belongs. We recommend selecting a custom namespace or the system-created default namespace. For details about namespaces, see Namespace overview.
Name	Specify a name for the PVC. The name must be unique within the cluster.
StorageClass type	Select the storage type. In this scenario, select Elastic NAS.
Access mode	Select a PVC access mode. You can select ReadWriteMany, which enables read and write access by multiple nodes.
Billing type	Select a resource billing type as needed. Currently, pay-as-you-go is supported.
How to create	Configure the method for creating a PVC. In this scenario, select Use an existing PersistentVolume.
PersistentVolume	Select the created PV for binding.

Click Confirm.

Step 3: Create an application and mount the PV

After the static PV of the EFS type is created, add the PV to a workload that will use the PV. Supported workloads include Deployment, StatefulSet, Job, CronJob, and DaemonSet.

You can add a PV to a workload when creating it or updating it. For details, see Workloads.

Creating through kubectl

Step 1: Create a PV

Create a YAML file for the PV. The following vke-nas-static-pv.yaml file serves as an example:

apiVersion: v1
kind: PersistentVolume
metadata:
name: vke-efs-static-pv
spec:
capacity:
storage: 20Gi # The PV capacity. This field is required by Kubernetes only for validation. It does not impose an actual capacity limit.
accessModes:
- ReadWriteMany # PV access mode. The only supported mode is ReadWriteMany, which allows read and write access by multiple nodes.
csi:
driver: nas.csi.volcengine.com # Driver required for storage mount.
volumeAttributes:
type: efs # The PV type, which needs to be set to efs.
server: cnshbe27f6ad23bd8.3qda7dut***.efs.ivolces.com # The domain of the EFS filesystem mount point.
path: / # The subdirectory of the file system for mounting.
volumeHandle: vke-efs-static-pv # The unique identifier of the PV. Keep it consistent with the PV name. To use multiple PVs simultaneously, the value for each PV must be different.
mountOptions:
- nolock,proto=tcp,noresvport
- vers=3 # The NFS version. Value: 3 (indicating NFSv3) or 4.1 (indicating NFSv4.1).
persistentVolumeReclaimPolicy: Delete # PV reclaim policy. Value: Retain or Delete.
volumeMode: Filesystem # The PV type. Value: Filesystem (using the volume as a filesystem. It will be mounted by the pod to a directory) or Block (using the volume as a block device).

The key parameters are described in the following table.

Parameter	Description
storage	Declared PV capacity. Unit: Gi. This field is required by Kubernetes. The value has no actual meaning and is only for validation. The actual capacity is subject to the created storage capacity.
accessModes	The PV access mode. Only ReadWriteMany is supported, which allows the PV to be read and written by multiple pods.
driver	The driver for mounting a PV. In this example, you need to set the value to nas.csi.volcengine.com, which indicates the csi-nas add-on.
type	The PV type. In this example, set it to efs.
server	The domain of the EFS filesystem mount point.
path	The subdirectory of the filesystem to be mounted. It defaults to the root directory ("/"). Ensure that the specified directory exists. Otherwise, the mount will fail.
volumeHandle	The unique identifier of the PV. Keep it consistent with the name of the PV.
mountOptions	Configure PV mount parameters, which support dynamic modification and only take effect on newly mounted PVs instead of those already mounted. You can use the vers parameter to specify the NFS version number for mounting the PV. Valid values: 3: Indicates NFSv3. 4.1: Indicates NFSv4.1.
persistentVolumeReclaimPolicy	The PV reclaim policy. The following information is included: Retain: The Retain policy. When the PVC bound to the PV is deleted, the PV is retained. Delete: The Delete policy. When the PVC bound to the PV is deleted, the PV is deleted synchronously.
volumeMode	The PV types. Valid values: Filesystem: (Default) Use the PV as a file system. The PV will be formatted and mounted to a file system (such as ext4 and xfs), and the file system will be mounted to a specified path in the container. You can use the ls command (such as ls /data) in the container to view the mounted directories or files, and directly read and write files. Block: Use the PV as a block device. It is directly exposed to the container without being formatted or mounted to a file system. You can perform operations on the block device by using paths such as /dev/block/xxx, and applications must support read and write operations on the raw block device.

Run the following command to create the PV.

kubectl create -f vke-nas-static-pv.yaml

Step 2: Create a PVC

Create a YAML file for the PVC. The following vke-efs-static-pvc.yaml file serves as an example:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: vke-efs-static-pvc # PVC name.
namespace: default # Namespace to which the PVC belongs.
spec:
accessModes:
- ReadWriteMany # PV access mode. Only ReadWriteMany is supported. ReadWriteMany allows read and write access from multiple nodes.
resources:
requests:
storage: 20Gi # Declared storage usage. The unit is Gi. Ensure it is consistent with the capacity of the created PV.
volumeMode: Filesystem # The PV type. Valid values: Filesystem (using the PV as a filesystem) and Block (using the PV as a block device). The value must be consistent with the type configured in the PV.
volumeName: vke-efs-static-pv # Name of the created PV.

The key parameters are described in the following table.

Parameter	Description
accessModes	The PVC access mode. You can only select ReadWriteMany, which enables read and write access by multiple nodes.
storage	The declared storage capacity. Unit: Gi. It must be consistent with the capacity of the created PV.
volumeMode	The PV type. It must be consistent with the type configured for the PV. The following information is included: Filesystem: (Default) Use the PV as a file system. The PV will be formatted and mounted to a file system (such as ext4 and xfs), and the file system will be mounted to a specified path in the container. You can use the ls command (such as ls /data) in the container to view the mounted directories or files, and directly read and write files. Block: Use the volume as a block device. It is directly exposed to the container without being formatted or mounted to a file system. You can perform operations on the block device by using paths such as /dev/block/xxx, and applications must support read and write operations on the raw block device.
volumeName	The name of the PV, which must be consistent with the name configured for the PV.

Run the following command to create the PVC.

kubectl create -f vke-efs-static-pvc.yaml

Run the following command to view the static binding result of the PVC and PV.

kubectl get pvc

If the response is similar to the following one, the binding is successful.

NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
vke-efs-static-pvc Bound vke-efs-static-pv 20Gi RWX 8s

Step 3: Create an application and mount the PV

Create a YAML file for the Deployment. The following vke-nas-static-deployment.yaml file is an example:

apiVersion: apps/v1
kind: Deployment
metadata:
name: vke-efs-static-deployment
namespace: default
labels:
app: nginx
spec:
replicas: 1
selector:
matchLabels:
app: vke-efs-static-deployment
template:
metadata:
labels:
app: vke-efs-static-deployment
spec:
containers:
- image: doc-cn-beijing.cr.volces.com/vke/nginx-demo:v1.0
name: nginx
volumeMounts:
- mountPath: /tmp # Mount location of the PV in the container.
name: nas-pv
volumes:
- name: nas-pv
persistentVolumeClaim:
claimName: vke-efs-static-pvc # The name of the created PVC.

Run the following command to create the Deployment.

kubectl create -f vke-nas-static-deployment.yaml

Validating results

After creating a workload and mounting a PV to it as described in the preceding steps, you can verify the volume mounting status and persistent storage via the following methods.

Run the following command to check whether the PV is mounted to the specified path in the pod.

kubectl exec vke-efs-static-deployment-xxx -- df | grep tmp

The expected response is as follows.

cnshbe27***.3qda7dutskr***.efs.ivolces.com:/ 10995116277760 0 10995116277760 0% /tmp

Check the mount path in the pod to view the data in the PV.

kubectl exec vke-nas-static-deployment-xxx -- ls /tmp

The expected response is as follows.

lost+found

Write a file to the PV.

kubectl exec vke-nas-static-deployment-xxx -- touch /tmp/test

Delete the pod.

kubectl delete pod vke-nas-static-deployment-xxx

Check the mount path of the PV in the newly created pod.

kubectl exec vke-nas-static-deployment-xxx -- ls /tmp

The expected result is as follows. You can see that the file written to the PV still exists and is not deleted along with the pod. This indicates that persistent storage of data is achieved.

lost+found
test