Using Pre-provisioned Volumes

This document describes how to use a pre-provisioned volume in your Kubernetes cluster.

Creating Portworx volume using pxctl

First create a volume using Portworx CLI. On one of the nodes with Portworx installed run the following command:

/opt/pwx/bin/pxctl volume create <vol-name> --size <size>

For more details on creating volumes using pxctl, click here.

Alternatively, you can also use snapshots that you created previously. To learn more, click here.

Using the Portworx volume

Once you have a Portworx volume, you can use it in 2 different ways:

1. Using the Portworx volume directly in a pod

You can create a pod that directly uses a Portworx volume as follows:

apiVersion: v1
kind: Pod
metadata:
   name: nginx-px
spec:
   containers:
   - image: nginx
     name: nginx-px
     volumeMounts:
     - mountPath: /test-portworx-volume
       name: testvol
   volumes:
   - name: testvol
     # This Portworx volume must already exist.
     portworxVolume:
       volumeID: testvol

Above testvol is the existing Portworx volume created using pxctl.

2. Using the Portworx volume by creating a PersistentVolume & PersistentVolumeClaim

Creating PersistentVolume

First create a PersistentVolume that references the Portworx volume. Following is an example spec.

apiVersion: v1
kind: PersistentVolume
metadata:
  name: testvol
  labels:
    name: testvol
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  portworxVolume:
    volumeID: testvol

Above PersistentVolume references an existing Portworx volume testvol (Notice that metadata.name and spec.portworxVolume.volumeID must be volume-name-or-ID) created using pxctl. Also note that it also has labels. We’ll soon see how they can be useful.

Creating PersistentVolumeClaim

Now create a PersistentVolumeClaim that will claim the above created volume. Following is an example spec.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: testvol-pvc
spec:
  selector:
    matchLabels:
      name: testvol
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi

Notice how we use a label selector to select the right PersistentVolume using it’s label.

Creating a pod using the PersistentVolumeClaim

Now you can create a pod that references the above PersistentVolumeClaim. Below is an example.

apiVersion: v1
kind: Pod
metadata:
   name: nginx-px
spec:
  containers:
  - image: nginx
    name: nginx-px
    volumeMounts:
    - mountPath: /test-portworx-volume
      name: testvol
  volumes:
  - name: testvol
    persistentVolumeClaim:
      claimName: testvol-pvc