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.