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Manually create and use a volume with Azure disks in Azure Kubernetes Service (AKS)

  • Article
  • 3 minutes to read

Container-based applications often need to access and persist data in an external data volume. If a single pod needs access to storage, you can use Azure disks to present a native volume for application use. This article shows you how to manually create an Azure disk and attach it to a pod in AKS.

Note

An Azure disk can only be mounted to a single pod at a time. If you need to share a persistent volume across multiple pods, use Azure Files.

For more information on Kubernetes volumes, see Storage options for applications in AKS.

Before you begin

This article assumes that you have an existing AKS cluster with 1.21 or later version. If you need an AKS cluster, see the AKS quickstart using the Azure CLI, using Azure PowerShell, or using the Azure portal.

If you want to interact with Azure Disks on an AKS cluster with 1.20 or previous version, see the Kubernetes plugin for Azure Disks.

Create an Azure disk

When you create an Azure disk for use with AKS, you can create the disk resource in the node resource group. This approach allows the AKS cluster to access and manage the disk resource. If you instead create the disk in a separate resource group, you must grant the Azure Kubernetes Service (AKS) managed identity for your cluster the Contributor role to the disk's resource group.

For this article, create the disk in the node resource group. First, get the resource group name with the az aks show command and add the --query nodeResourceGroup query parameter. The following example gets the node resource group for the AKS cluster name myAKSCluster in the resource group name myResourceGroup:

$ az aks show --resource-group myResourceGroup --name myAKSCluster --query nodeResourceGroup -o tsv

MC_myResourceGroup_myAKSCluster_eastus

Now create a disk using the az disk create command. Specify the node resource group name obtained in the previous command, and then a name for the disk resource, such as myAKSDisk. The following example creates a 20GiB disk, and outputs the ID of the disk once created. If you need to create a disk for use with Windows Server containers, add the --os-type windows parameter to correctly format the disk.

az disk create \
  --resource-group MC_myResourceGroup_myAKSCluster_eastus \
  --name myAKSDisk \
  --size-gb 20 \
  --query id --output tsv

Note

Azure disks are billed by SKU for a specific size. These SKUs range from 32GiB for S4 or P4 disks to 32TiB for S80 or P80 disks (in preview). The throughput and IOPS performance of a Premium managed disk depends on both the SKU and the instance size of the nodes in the AKS cluster. See Pricing and Performance of Managed Disks.

The disk resource ID is displayed once the command has successfully completed, as shown in the following example output. This disk ID is used to mount the disk in the next step.

/subscriptions/<subscriptionID>/resourceGroups/MC_myAKSCluster_myAKSCluster_eastus/providers/Microsoft.Compute/disks/myAKSDisk

Mount disk as volume

Create a pv-azuredisk.yaml file with a PersistentVolume. Update volumeHandle with disk resource ID. For example:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-azuredisk
spec:
  capacity:
    storage: 20Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: managed-csi
  csi:
    driver: disk.csi.azure.com
    readOnly: false
    volumeHandle: /subscriptions/<subscriptionID>/resourceGroups/MC_myAKSCluster_myAKSCluster_eastus/providers/Microsoft.Compute/disks/myAKSDisk
    volumeAttributes:
      fsType: ext4

Create a pvc-azuredisk.yaml file with a PersistentVolumeClaim that uses the PersistentVolume. For example:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-azuredisk
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi
  volumeName: pv-azuredisk
  storageClassName: managed-csi

Use the kubectl commands to create the PersistentVolume and PersistentVolumeClaim.

kubectl apply -f pv-azuredisk.yaml
kubectl apply -f pvc-azuredisk.yaml

Verify your PersistentVolumeClaim is created and bound to the PersistentVolume.

$ kubectl get pvc pvc-azuredisk

NAME            STATUS   VOLUME         CAPACITY    ACCESS MODES   STORAGECLASS   AGE
pvc-azuredisk   Bound    pv-azuredisk   20Gi        RWO                           5s

Create a azure-disk-pod.yaml file to reference your PersistentVolumeClaim. For example:

apiVersion: v1
kind: Pod
metadata:
  name: mypod
spec:
  containers:
  - image: mcr.microsoft.com/oss/nginx/nginx:1.15.5-alpine
    name: mypod
    resources:
      requests:
        cpu: 100m
        memory: 128Mi
      limits:
        cpu: 250m
        memory: 256Mi
    volumeMounts:
      - name: azure
        mountPath: /mnt/azure
  volumes:
    - name: azure
      persistentVolumeClaim:
        claimName: pvc-azuredisk

kubectl apply -f azure-disk-pod.yaml

Next steps

For associated best practices, see Best practices for storage and backups in AKS.