Use an Azure File share | Anthos clusters on Azure

Anthos clusters on Azure supports mounting Azure Files shares. If you already have an Azure File share to use with Anthos clusters on Azure, you can create a PersistentVolume (PV) object and reserve it for a specific PersistentVolumeClaim (PVC).

This page explains how to create a PV by using an existing share populated with data, and how to use the PV in a Pod.

Before you begin

Connect to your cluster
Have access to or create an Azure File share. For more information, see Create an Azure file share.

Store your Azure storage account information

Anthos clusters on Azure stores information to access your Azure storage account in a Secret. If you haven't created a Secret in your cluster, you must add one. If you have this Secret in you cluster, skip to Create a PersistentVolume for a pre-existing share.

To create the Secret, copy the following manifest into a file named 'azure-service-account-key.yaml'.
```
---
apiVersion: v1
kind: Secret
metadata:
  name: azure-secret-account-key
type: Opaque
stringData:
  accountname: STORAGE_ACCOUNT_NAME
  accountkey: STORAGE_ACCOUNT_KEY
```
Replace the following:
- STORAGE_ACCOUNT_NAME: your Azure storage account name
- STORAGE_ACCOUNT_KEY: your Azure storage account key
Apply the file to your cluster with the kubectl tool:
```
kubectl apply -f azure-service-account-key.yaml
```

Create a PersistentVolume for a pre-existing share

You import an existing Azure File share by specifying a new PV in your cluster. To create the PV, do the following:

Copy the following YAML into a file named existing-volume.yaml:
```
apiVersion: v1
kind: PersistentVolume
metadata:
  name: VOLUME_NAME
spec:
  capacity:
    storage: VOLUME_CAPACITY
  storageClassName: standard-rwx
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  csi:
    driver: file.csi.azure.com
    readOnly: false
    volumeHandle: VOLUME_ID
```
Replace the following:
- VOLUME_NAME: a name for the volume
- VOLUME_CAPACITY: size of the volume. For example, 30Gi. For more information on specifying volume capacity in Kubernetes, see the Meaning of memory.
- VOLUME_ID: a unique ID for the volume, formatted as a string of RESOURCE_GROUP_NAME#STORAGE_ACCOUNT_NAME#FILESHARE_NAME# where
- FILE_SHARE_NAME: the Azure File share name
If your storage account is in a different resource group than your cluster, you need to add a reference to a Secret that contains your storage account key. To add the reference, insert the following in the spec.csi section:
```
# Optional. Only required if your storageAccount is in a different resource group than the cluster.
    nodeStageSecretRef:
      name: NODE_STAGE_SECRET_NAME
      namespace: NODE_STAGE_SECRET_NAMESPACE
```
Replace the following:
- NODE_STAGE_SECRET_NAME: the name of the Secret
- NODE_STAGE_SECRET_NAMESPACE the Namespace that contains the Secret
Apply the YAML to your cluster.
```
kubectl apply -f existing-volume.yaml
```
Confirm the creation of your PV with kubectl describe pv.
```
kubectl describe pv VOLUME_NAME
```
The output of this command contains the status of the PV.

Use the volume with a PersistentVolumeClaim and Pod

After you have imported your volume, you can create a PVC and a Pod that mounts the PVC.

The following YAML creates a PVC and attaches it to a Pod running the Nginx web server. Copy it into a file named nginx.yaml:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
spec:
  storageClassName: STORAGE_CLASS_NAME
  volumeName: VOLUME_NAME
  accessModes:
    - ACCESS_MODE
  resources:
    requests:
      storage: VOLUME_CAPACITY
---

apiVersion: v1
kind: Pod
metadata:
  name: web-server
spec:
  containers:
   - name: web-server
     image: nginx
     volumeMounts:
       - mountPath: /var/lib/www/html
         name: data
  volumes:
   - name: data
     persistentVolumeClaim:
       claimName: my-pvc

Replace the following:

STORAGE_CLASS: the name of the StorageClass from the PersistentVolume you created previously. For example, standard-rwo.
ACCESS_MODE: the access mode of the volume. For Azure Disk, use ReadWriteOnce. For Azure File, use ReadWriteMany.
VOLUME_CAPACITY: size of the volume. For example, 30Gi.

Apply the YAML to your cluster.
```
kubectl apply -f nginx.yaml
```
Check the status of your Nginx instance with kubectl describe. The output should have a STATUS of Running.
```
kubectl describe pod web-server
```
To delete the Pod, use the kubectl delete command.
```
kubectl delete -f nginx.yaml
```

What's next

Use additional storage drivers with Anthos clusters on Azure.
Read the documentation for the Azure File CSI driver.