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Connect Azure Elastic SAN volumes to an Azure Kubernetes Service cluster

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This article explains how to connect an Azure Elastic storage area network (SAN) volume from an Azure Kubernetes Service (AKS) cluster. To make this connection, enable the Kubernetes iSCSI CSI driver on your cluster. With this driver, you can access volumes on your Elastic SAN by creating persistent volumes on your AKS cluster, and then attaching the Elastic SAN volumes to the persistent volumes.

About the driver

The iSCSI CSI driver is an open source project that allows you to connect to a Kubernetes cluster over iSCSI. Since the driver is an open source project, Microsoft won't provide support from any issues stemming from the driver, itself.

The Kubernetes iSCSI CSI driver is available on GitHub:

Licensing

The iSCSI CSI driver for Kubernetes is licensed under the Apache 2.0 license.

Prerequisites

Limitations

  • Dynamic provisioning isn't currently supported
  • Only ReadWriteOnce access mode is currently supported

Get started

Driver installation

curl -skSL https://raw.githubusercontent.com/kubernetes-csi/csi-driver-iscsi/master/deploy/install-driver.sh | bash -s master --

After deployment, check the pods status to verify that the driver installed.

kubectl -n kube-system get pod -o wide -l app=csi-iscsi-node

Get volume information

You need the volume's StorageTargetIQN, StorageTargetPortalHostName, and StorageTargetPortalPort.

You can get them with the following Azure PowerShell command:

Get-AzElasticSanVolume -ResourceGroupName $resourceGroupName -ElasticSanName $sanName -VolumeGroupName $searchedVolumeGroup -Name $searchedVolume

You can also get them with the following Azure CLI command:

az elastic-san volume show --elastic-san-name --name --resource-group --volume-group-name

Cluster configuration

Once you've retrieved your volume's information, you need to create a few yaml files for your new resources on your AKS cluster.

Storageclass

Use the following example to create a storageclass.yml file. This file defines your persistent volume's storageclass.

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: san-volume
provisioner: manual

Persistent volume

After you've created the storage class, create a pv.yml file. This file defines your persistent volume. In the following example, replace yourTargetPortal, yourTargetPortalPort, and yourIQN with the values you collected earlier, then use the example to create a pv.yml file. If you need more than 1 gibibyte of storage and have it available, replace 1Gi with the amount of storage you require.

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: iscsiplugin-pv
  labels:
    name: data-iscsiplugin
spec:
  storageClassName: san-volume
  accessModes:
    - ReadWriteOnce
  capacity:
    storage: 1Gi
  csi:
    driver: iscsi.csi.k8s.io
    volumeHandle: iscsi-data-id
    volumeAttributes:
      targetPortal: "yourTargetPortal:yourTargetPortalPort"
      portals: "[]"
      iqn: "yourIQN"
      lun: "0"
      iscsiInterface: "default"
      discoveryCHAPAuth: "true"
      sessionCHAPAuth: "false"

After creating the pv.yml file, create a persistent volume with the following command:

kubectl apply -f pathtoyourfile/pv.yaml

Persistent volume claim

Next, create a persistent volume claim. Use the storage class we defined earlier with the persistent volume we defined. The following is an example of what your pvc.yml file might look like:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: iscsiplugin-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: san-volume
  selector:
    matchExpressions:
      - key: name
        operator: In
        values: ["data-iscsiplugin"]

After creating the pvc.yml file, create a persistent volume claim.

kubectl apply -f pathtoyourfile/pvc.yaml

To verify your PersistentVolumeClaim is created and bound to the PersistentVolume, run the following command:

kubectl get pvc pathtoyourfile

Finally, create a pod manifest. The following is an example of what your pod.yml file might look like. You can use it to make your own pod manifest, replace the values for name, image, and mountPath with your own:

apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
    - image: maersk/nginx
      imagePullPolicy: Always
      name: nginx
      ports:
        - containerPort: 80
          protocol: TCP
      volumeMounts:
        - mountPath: /var/www
          name: iscsi-volume
  volumes:
    - name: iscsi-volume
      persistentVolumeClaim:
        claimName: iscsiplugin-pvc

After creating the pod.yml file, create a pod.

kubectl apply -f pathtoyourfile/pod.yaml

To verify your Pod was created, run the following command:

kubectl get pods

You've now successfully connected an Elastic SAN volume to your AKS cluster.

Next steps

Plan for deploying an Elastic SAN