Creating Persistent File System Storage Using the CSI Volume Plugin

On Compute Cloud@Customer, you can provision a PVC on a new file system using the CSI volume plugin. Use the kubectl command to create the storage class and persistent volume claim. The CSI volume plugin provisions the PVC on a new file system.

You can have only one mount target and one file system per VCN. You can have multiple storage classes, persistent volumes, and persistent volume claims per cluster. All storage classes, persistent volumes, and persistent volume claims in a cluster share one NFS.

Create a new storage class that uses the fss.csi.oraclecloud.com provisioner.
```
$ kubectl create -f sc.yaml
```
The following is the content of the sc.yaml manifest file:
```
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: fss-dyn-storage
provisioner: fss.csi.oraclecloud.com
parameters:
  availabilityDomain: AD-1
  compartmentOcid: ocid1.compartment.unique_ID
  mountTargetSubnetOcid: ocid1.subnet.unique_ID
  exportPath: AUTOSELECT
  exportOptions: "[{\"source\":\"0.0.0.0/0\",\"requirePrivilegedSourcePort\":false,\"access\":\"READ_WRITE\",\"identitySquash\":\"NONE\"}]"
  encryptInTransit: "false"
```
- The name for the new storage class is fss-dyn-storage.
- Either mountTargetSubnetOcid or mountTargetOcid is required. The value of mountTargetSubnetOcid is the OCID of the subnet where you want the CSI plugin to create a mount target. The value of mountTargetOcid is the OCID of an existing mount target. If you specify both mountTargetSubnetOcid and mountTargetOcid, mountTargetOcid is used and mountTargetSubnetOcid is ignored.
  
  To ensure that the mount target can be reached from worker nodes, specify the subnet that has configuration like the "worker" subnet described in Creating an OKE Worker Subnet or create the mount target on the subnet that has configuration like the worker subnet. Ensure that TCP port 2049 to the NFS server is open on that subnet.
- The compartmentOcid is optional. This value is the OCID of the compartment where the new file system (and the new mount target, if mountTargetSubnetOcid is specified) will be created. The default value is the same compartment as the cluster.
- You must specify AUTOSELECT as the value for exportPath.
- The exportOptions value is the NFS export options entry within the file system export that defines the access granted to NFS clients when they connect to a mount target. The source can be a single IP address or CIDR block range. This value is a set of parameters in JSON format.
- The value of encryptInTransit specifies whether to encrypt data in transit.

Create a PVC to be provisioned by the new file system in the File Storage service.

$ kubectl create -f fss-dyn-claim.yaml

The following is the content of the fss-dyn-claim.yaml manifest file:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: fss-dynamic-claim
spec:
  accessModes:
  - ReadWriteMany
  storageClassName: "fss-dyn-storage"
  resources:
    requests:
      storage: 50Gi

Verify that the PVC has been bound to the new persistent volume.

$ kubectl get pvc
NAME              STATUS VOLUME                                       CAPACITY ACCESS MODES STORAGECLASS    AGE
fss-dynamic-claim Bound  csi-fss-f6823a66-8b6f-4c42-9d1f-d25723e69257 50Gi     RWX          fss-dyn-storage 6m47s

Use the new PVC when you create objects such as pods.

The following is an example object creation:

$ kubectl create nginx.yaml

The following is the content of the nginx.yaml file. See the claimName on the last line:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx_image_url
        ports:
        - name: http
          containerPort: 80
        volumeMounts:
        - name: persistent-storage
          mountPath: /usr/share/nginx/html
      volumes:
      - name: persistent-storage
        persistentVolumeClaim:
          claimName: fss-dynamic-claim

Verify that the object is created and deployed:

$ kubectl get deploy
NAME             READY UP-TO-DATE AVAILABLE AGE
nginx-deployment 3/3   3          0         104s

Oracle Cloud Infrastructure Documentation

Creating Persistent File System Storage Using the CSI Volume Plugin