How To Create Pvc In Kubernetes

Create Kubernetes Persistent Volume

demo

Kubernetes provides a Persistent Volume subsystem that abstracts details of how storage is provided from how it is consumed. You still need to provide the underlying storage system.

Ondat provides cloud native storage for Kubernetes used for provisioning Persistent Volumes. Get started in four steps:

Install etcd
Install StorageOS Operator
Create a Kubernetes secret detailing the default Ondat administrator account
Install Ondat using a StorageOSCluster Custom Resource

Ondat Kubernetes Persistent Volume Guide

As a simple first use of Ondat with Kubernetes following the example below will create a PersistentVolumeClaim (PVC) and schedule a Pod to mount the PersistentVolume (PV) provisioned by the PVC. You can read more details about Ondat and Kubernetes best practices at our docs.

Creating the PersistentVolumeClaim

You can find the latest files in the Ondat example deployment repository

                    git clone https://github.com/storageos/deploy.git storageos

PVC definition

                                          apiVersion                      :                      v1                      kind                      :                      PersistentVolumeClaim                      metadata                      :                      name                      :                      my-vol-1                      spec                      :                      storageClassName                      :                      "                      fast"                      accessModes                      :                      -                      ReadWriteOnce                      resources                      :                      requests                      :                      storage                      :                      5Gi

The above PVC will dynamically provision a 5GB volume using the fast StorageClass. This StorageClass was created during the Ondat install and causes Ondat to provision a PersistentVolume.

                                          apiVersion                      :                      v1                      kind                      :                      PersistentVolumeClaim                      metadata                      :                      name                      :                      my-vol-1                      labels                      :                      storageos.com/replicas                      :                      "                      1"                      spec                      :                      storageClassName                      :                      "                      fast"                      accessModes                      :                      -                      ReadWriteOnce                      resources                      :                      requests                      :                      storage                      :                      5Gi

The above PVC has the storageos.com/replicas label set. This label tells Ondat to create a replica for the volume that is created. For the sake of keeping this example simple, the unreplicated volume will be used.

Move into the examples folder and create a PVC using the PVC definition above.

                                          $                                            cd                      storageos                      $                      kubectl create                      -f                      ./k8s/examples/pvc.yaml

You can view the PVC that you have created with the command below

$ kubectl get pvc

NAME	STATUS	VOLUME	CAPACITY	ACCESS MODES	STORAGECLASS	AGE
my-vol-1	Bound	pvc-f8ffa027-e821-11e8-bc0b-0ac77ccc61fa	5Gi	RWO	fast	1m

Create a pod that mounts the PVC created in step 2.

                                          $                      kubectl create                      -f                      ./k8s/examples/debian-pvc.yaml

The command above creates a Pod that uses the PVC that was created in step 1.

                                          apiVersion                      :                      v1                      kind                      :                      Pod                      metadata                      :                      name                      :                      d1                      spec                      :                      containers                      :                      -                      name                      :                      debian                      image                      :                      debian:9-slim                      command                      :                      [                      "                      /bin/sleep"                      ]                      args                      :                      [                      "                      3600"                      ]                      volumeMounts                      :                      -                      mountPath                      :                      /mnt                      name                      :                      v1                      volumes                      :                      -                      name                      :                      v1                      persistentVolumeClaim                      :                      claimName                      :                      my-vol-1

In the Pod definition above the volume v1, which references the PVC created in step 2, is mounted in the pod at /mnt. In this example, a debian image is used for the container but any container image with a shell would work for this example.

Confirm that the pod is up and running

                                          $                      kubectl get pods  NAME      READY   STATUS    RESTARTS   AGE  d1        1/1     Running   0          1m

Execute a shell inside the container and write some contents to a file

By writing to /mnt inside the container, the StorageOS volume created by the PVC is being written to. If you were to kill the pod and start it again on a new node, the helloworld file would still be available.