AKS: Resize Private Volume Claim to expand a Managed Premium Disk

AKS: Resize Private Volume Claim to expand a Managed Premium Disk
By Carlos Mendible |
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  2 minute read  

If you deployed a private volume claim using the managed-premium storage class, then ran out of space and now you are searching how to expand the disk to a larger disk, this is how you can do it from scratch:

manage-premium storage class is a premium storage class that allows volume expansion: allowVolumeExpansion: true.

Create a private volume claim using a managed-premium storage class:

Create a pvc.yaml file with the following contents:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nginx-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 128Gi
  storageClassName: managed-premium

and deploy it to your cluster:

kubectl apply -f pvc.yaml

Create a deployment that uses the PVC:

Create a deployment.yaml file with the following contents:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        volumeMounts:
        - mountPath: "/mnt/azure"
          name: volume
      volumes:
        - name: volume
          persistentVolumeClaim:
            claimName: nginx-pvc

and deploy it to your cluster:

kubectl apply -f deployment.yaml

Check the PVC status:

To check the status of the PVC, run the following command:

kubectl get pvc -w

Create a test file by running the following command:

kubectl exec -it $(kubectl get po -l "app=nginx" -o name) -- sh -c "echo 'Very important file' > /mnt/azure/test.file"

Resize the PVC and expand the disk:

Scale the deployment to 0 replicas:

kubectl scale --replicas=0 deployment nginx

Check the status of the attached disk:

$resourceGroupName="<your aks resource group>"
$aksName="<your aks name>"
$resourceGroup=$(az aks show --resource-group $resourceGroupName --name $aksName --query "nodeResourceGroup" --output tsv)
az disk list --resource-group $resourceGroup --query "[[0].diskState, [0].diskSizeGb]"

You should get the following result:

[
  "Unattached",
  256
]

Note: I only had one disk attached to the AKS cluster, so I am using the first disk.

Resize the PVC:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nginx-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 256Gi
  storageClassName: managed-premium
  volumeName: nginx-pv

and deploy it to your cluster:

kubectl apply -f pvc.yaml

Scale the deployment back to 1 replicas:

kubectl scale --replicas=1 deployment nginx

and check the po status:

kubectl get po -w

Check the size of the disk:

Check again the status and size of the attached disk:

$resourceGroupName="<your aks resource group>"
$aksName="<your aks name>"
$resourceGroup=$(az aks show --resource-group $resourceGroupName --name $aksName --query "nodeResourceGroup" --output tsv)
az disk list --resource-group $resourceGroup --query "[[0].diskState, [0].diskSizeGb]"

You should get the following result:

[
  "Attached",
  256
]

and finally check the contents of the test file:

kubectl exec $(kubectl get po -l "app=nginx" -o name) -- sh -c "cat /mnt/azure/test.file"

Hope it helps!!!

Last modified December 12, 2024: new post (bf52b37)