NAS volume CSI

Available in VPC

If you add files to a running container, all files are deleted when the process is terminated or the container is restarted due to a failed Kubernetes Liveness Probe check. You can use NAS volumes so that newly added files are retained even after the process ends or the container restarts.

You can create and attach a PersistentVolumeClaim (PVC) when deploying a container that uses a NAS volume.

NAVER Cloud Platform's Ncloud Kubernetes Service provides the Container Storage Interface (CSI) as its volume driver. This driver integrates with Kubernetes and supports tasks such as NAS volume creation, deletion, and resizing.

Supported versions and capacity

This section describes supported versions and capacity.

Supported versions

The following are the NAS CSI versions provided by NAVER Cloud Platform and the compatible Kubernetes versions:

The following storage services are supported by the Kubernetes version:

Assignable capacity

You can allocate capacity to Kubernetes NAS volumes in units of 100 GB using CSI. If you do not specify the volume size, a NAS volume is created with the default size of 500 GB. The minimum and maximum allocatable capacity are as follows:

• Minimum: 500 GB
• Maximum: 10,000 GB

Install the NAS CSI driver (for existing clusters without it installed)

The NAS CSI driver is deployed by default when Kubernetes is installed. This section describes how to install NAS CSI on an existing cluster where it is not installed. If NAS CSI is already installed, you do not need to perform the following tasks.

Deploy the NAS CSI driver

The following files refer to the latest stable version. If a problem occurs during installation, run the kubectl apply -f command again to apply any missing resources.

• Korea Region

# kubernetes version >= 1.22
$ kubectl --kubeconfig=$KUBE_CONFIG apply -f https://kr.object.ncloudstorage.com/nks-download/nas-csi/pub/kr/v2.2.0/nas-csi.yaml

# kubernetes version < 1.22
$ kubectl --kubeconfig=$KUBE_CONFIG apply -f https://kr.object.ncloudstorage.com/nks-download/nas-csi/pub/kr/v1.0.2/nas-csi.yaml

• Singapore Region

# kubernetes version >= 1.22
$ kubectl --kubeconfig=$KUBE_CONFIG apply -f https://kr.object.ncloudstorage.com/nks-download/nas-csi/pub/sgn/v2.2.0/nas-csi.yaml

# kubernetes version < 1.22
$ kubectl --kubeconfig=$KUBE_CONFIG apply -f https://kr.object.ncloudstorage.com/nks-download/nas-csi/pub/sgn/v1.0.2/nas-csi.yaml

• Japan Region

# kubernetes version >= 1.22
$ kubectl --kubeconfig=$KUBE_CONFIG apply -f https://kr.object.ncloudstorage.com/nks-download/nas-csi/pub/jpn/v2.2.0/nas-csi.yaml

NAS CSI driver details

StorageClass

StorageClass is an object that defines the policy and type of each storage. NAVER Cloud Platform provides a StorageClass that uses NAS volumes.
To check the StorageClass object for NAS volumes, check the object named nks-nas-csi. It is displayed as follows:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nks-nas-csi
mountOptions:
- hard
- nolock
- nfsvers=3
parameters:
  csi.storage.k8s.io/provisioner-secret-name: mount-options
  csi.storage.k8s.io/provisioner-secret-namespace: kube-system
provisioner: nas.csi.ncloud.com
reclaimPolicy: Delete
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true

• volumeBindingMode: Configures when volume binding and dynamic provisioning are performed. The default value is "Immediate."

• reclaimPolicy: Configures the policy for reusing or deleting a PersistentVolume when the PVC is deleted. The default value is "Delete."

• allowVolumeExpansion: You can enable expansion of a PersistentVolumeClaim by setting this value to "true."

• parameters.subDir: You can create subdirectories within a single NAS volume and configure the subdirectory path under the NFS share path so that multiple PVCs can share the same NAS volume. If not specified, a subdirectory is created using the PV name. [NAS CSI v2.2.0+]

When you use the following patterns in the parameters.subDir value, they are automatically replaced with PVC/PV metadata:

• parameters.deleteOnlySubdir: Configures whether only the subdirectory is deleted when the PVC is deleted. The default value is false. [NAS CSI v2.2.0+]

Change the default StorageClass

To change the default StorageClass of a created StorageClass object, see Changing the default StorageClass.

CSI Controller

The CSI controller is an interface responsible for operations such as volume creation, deletion, attachment, detachment, and snapshot management.

To check the NAS CSI controller, run the following command to view the relevant Pods in the kube-system namespace:

$ kubectl --kubeconfig $KUBE_CONFIG get pods -n kube-system -l app=nks-nas-csi-controller

CSI Node

A CSI node runs on each Kubernetes worker node and is responsible for operations such as volume formatting, mounting, and unmounting.

To check the NAS CSI node, run the following command to view the relevant Pods in the kube-system namespace:

$ kubectl --kubeconfig $KUBE_CONFIG  get pods -n kube-system -l app=nks-nas-csi-node

Use the NAS CSI driver

For detailed examples of using the NAS CSI driver, see NAS volume CSI examples.