Use persistent volume in an AKS on Azure Stack HCI cluster
Applies to: AKS on Azure Stack HCI, AKS runtime on Windows Server 2019 Datacenter
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 lifecycle. While you can provision a PVC for both Windows and Linux nodes, in this section, you'll see how to create a persistent volume and how to use this volume 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 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 in the following YAML definition. The claim requests 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
Create the volume by running the following commands in an administrative PowerShell session on one of the servers in the Azure Stack HCI cluster (using a method such as Enter-PSSession or Remote Desktop to connect to the server):
kubectl create -f pvc-akshci-csi.yaml
The following output will show that your persistent volume claim has been created successfully:
Use persistent volume
To use a persistent volume, create a file named winwebserver.yaml and copy in the following YAML definition. You will then create a pod with access to the persistent volume claim and vhdx.
In the yaml definition below, mountPath is the path to mount a volume inside a container. After a successful pod creation, you will 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 the above yaml definition, run:
kubectl create -f winwebserver.yaml
To make sure the pod is running, run 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 deleting a persistent volume claim, you must delete the app deployment by running:
kubectl delete deployments win-webserver
You can then delete a persistent volume claim by running:
kubectl delete PersistentVolumeClaim pvc-akshci-csi