Dynamically provisioning persistent volumes

Persistent volumes can be dynamically provisioned via persistent volume claims (PVC). A PVC requests for a PV of a specific storage class, access mode, and size. If a suitable PV exists in the cluster, it is bound to the claim. If suitable PVs do not exist but can be provisioned, a new volume is created and bound to the claim. Kubernetes uses a PVC to obtain the PV backing it and mounts it to the pod.

Prerequisites

  • A pod and the persistent volume claim it uses must exist in the same namespace.

To dynamically provision a PV to a pod

  1. Access the Kubernetes cluster via the dashboard. Click Kubernetes access for instructions.
  2. On the Kubernetes dashboard, create a storage class, as described in Creating storage classes.
  3. Create a persistent volume claim. To do it, click + Create and specify the following YAML file:

    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      name: mypvc
    spec:
      accessModes:
      - ReadWriteOnce
      resources:
        requests:
          storage: 10Gi
      storageClassName: mysc
    

    This manifest specifies the persistent volume claim mypvc that requests from the storage class mysc a volume of at least 10 GiB that can be mounted in the read/write mode by a single node.

    Creation of the PVC triggers dynamic provisioning of a persistent volume that satisfies the claim’s requirements. Kubernetes then binds it to the claim.

  4. Create a pod and specify the PVC as its volume. To do it, click + Create and enter the following YAML file:

    apiVersion: v1
    kind: Pod
    metadata:
      name: nginx
    spec:
      containers:
      - image: nginx
        imagePullPolicy: IfNotPresent
        name: nginx
        ports:
        - containerPort: 80
          protocol: TCP
        volumeMounts:
          - mountPath: /var/lib/www/html
            name: mydisk
      volumes:
      - name: mydisk
        persistentVolumeClaim:
          claimName: mypvc
          readOnly: false
    

    This configuration file describes the pod nginx that uses the persistent volume claim mypvc. The persistent volume bound to the claim will be accessible at /var/lib/www/html inside the nginx container.