Use persistent volumes with AKS enabled by Arc
Applies to: AKS on Azure Stack HCI 22H2, AKS on Windows Server
This article describes how to provision, use, and delete persistent volumes that provide long-term storage for use with Kubernetes pods in AKS enabled by Azure Arc (AKS Arc).
A persistent volume represents a piece of storage that has been provisioned for use with Kubernetes pods. A persistent volume can be used by one or more pods and is meant for long-term storage. It's also independent of pod or node lifecycles.
While you can provision a persistent volume for both Windows and Linux nodes, this article describes how to create a persistent volume for use in your Windows application. For more information, see Persistent volumes in Kubernetes.
Before you begin
Here's what you need to get started:
- A Kubernetes cluster with at least one Windows worker node.
- A kubeconfig file to access the Kubernetes cluster.
Create a persistent volume claim
A persistent volume claim (PVC) is used to automatically provision storage based on a storage class. To create a volume claim, first create a file named pvc-akshci-csi.yaml
and copy and paste the following YAML definition. The PVC requires a disk that is 10 GB in size with ReadWriteOnce access. The default storage class is specified as the storage class (vhdx).
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: pvc-akshci-csi
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 10Gi
To create the volume, run the following commands in an administrative PowerShell session on one of the servers in the Azure Stack HCI cluster. Use a method such as Enter-PSSession or Remote Desktop to connect to the server.
kubectl create -f pvc-akshci-csi.yaml
The following output shows that your persistent volume claim was successfully created:
Output:
persistentvolumeclaim/pvc-akshci-csi created
Use persistent volume
To use a persistent volume, create a file named winwebserver.yaml
, and copy and paste the following YAML definition. Then, create a pod with access to the persistent volume claim and vhdx.
In the following YAML definition, mountPath
is the path to mount a volume inside a container. After a successful pod creation, you'll see the subdirectory mnt created in C:\ and the subdirectory akshciscsi created inside mnt:
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: win-webserver
name: win-webserver
spec:
replicas: 1
selector:
matchLabels:
app: win-webserver
template:
metadata:
labels:
app: win-webserver
name: win-webserver
spec:
containers:
- name: windowswebserver
image: mcr.microsoft.com/windows/servercore/iis:windowsservercore-ltsc2019
ports:
- containerPort: 80
volumeMounts:
- name: akshciscsi
mountPath: "/mnt/akshciscsi"
volumes:
- name: akshciscsi
persistentVolumeClaim:
claimName: pvc-akshci-csi
nodeSelector:
kubernetes.io/os: windows
To create a pod with this YAML definition, run:
kubectl create -f winwebserver.yaml
To make sure the pod is running, execute the following command. Wait a few minutes until the pod is in a running state, since pulling the image takes time:
kubectl get pods -o wide
Once your pod is running, view the pod status by running the following command:
kubectl.exe describe pod %podName%
To verify your volume has been mounted in the pod, run the following command:
kubectl exec -it %podname% cmd.exe
Delete a persistent volume claim
Before you delete a persistent volume claim, you must delete the app deployment by running the following command:
kubectl delete deployments win-webserver
You can then delete a persistent volume claim by running:
kubectl delete PersistentVolumeClaim pvc-akshci-csi