Using the Compute Engine persistent disk CSI Driver

Google Kubernetes Engine (GKE) provides a simple way for you to automatically deploy and manage the Compute Engine persistent disk Container Storage Interface (CSI) Driver in your clusters.

The Compute Engine persistent disk CSI Driver version is tied to GKE version numbers. The Compute Engine persistent disk CSI Driver version is typically the latest driver available at the time that the GKE version is released. The drivers update automatically when the cluster is upgraded to the latest GKE patch.

Benefits of using Compute Engine persistent disk CSI Driver

Using the Compute Engine persistent disk CSI Driver instead of the Kubernetes in-tree gcePersistentDisk volume plugin provides the following benefits:

  • CSI drivers are the future of storage extension in Kubernetes. Kubernetes has announced that the in-tree volume plugins are expected to be removed from Kubernetes in version 1.21. For details, see Kubernetes In-Tree to CSI Volume Migration Moves to Beta. After this change happens, existing volumes using in-tree volume plugins will communicate through CSI drivers instead.
  • It enables the automatic deployment and management of the persistent disk driver without having to manually set it up, or use the in-tree volume plugin.
  • It provides additional persistent disk features in GKE. For example:
    • You can use customer-managed encryption keys (CMEKs) with the Compute Engine persistent disk CSI Driver, but not the in-tree volume plugin. These keys are used to encrypt the data encryption keys that encrypt your data. To learn more about CMEK on GKE, see Using CMEK.
    • You can use volume snapshots with the Compute Engine persistent disk CSI Driver. Volume snapshots let you create a copy of your volume at a specific point in time. You can use this copy to bring a volume back to a prior state or to provision a new volume.
  • Bug fixes and feature updates are rolled out independently from minor Kubernetes releases. This typically results in a faster release cadence.

Requirements

To use Compute Engine persistent disk CSI Driver, you must use GKE versions that are 1.14 or later.

Enabling Compute Engine persistent disk CSI Driver on a new cluster

To use the Compute Engine persistent disk CSI Driver in new clusters, enable the feature using gcloud or the Google Cloud Console.

gcloud

By default, the Compute Engine persistent disk CSI Driver is not enabled when you create a cluster. To enable the driver on cluster creation, run the following command:

gcloud beta container clusters create cluster-name \
  --addons=GcePersistentDiskCsiDriver \
  --cluster-version=version

Replace the following:

  • cluster-name is the name of your new cluster.
  • version is the GKE version number. You must select a version of 1.14 or higher to use this feature.

For the full list of optional flags, refer to the gcloud container clusters create documentation.

Console

By default, Compute Engine persistent disk CSI Driver is not enabled when you create a cluster. To enable the driver on cluster creation:

  1. Visit the Google Kubernetes Engine menu in Cloud Console.

    Visit the Google Kubernetes Engine menu

  2. Click the Create cluster button.

  3. Configure your cluster as desired. For details on the types of clusters you can create, see Types of clusters.

  4. From the navigation pane, under Cluster, click Features.

  5. Select the Enable Compute Engine persistent disk CSI Driver checkbox.

  6. Click Create.

Once you have enabled Compute Engine persistent disk CSI Driver, the driver can then be used in Kubernetes volumes using the driver and provisioner name: pd.csi.storage.gke.io.

Enabling Compute Engine persistent disk CSI Driver on an existing cluster

To enable the Compute Engine persistent disk CSI Driver in existing clusters, use gcloud or the Google Cloud Console.

gcloud

To enable the driver on an existing cluster, run the following command:

 gcloud beta container clusters update cluster-name \
  --update-addons=GcePersistentDiskCsiDriver=ENABLED

Replace cluster-name with the name of the existing cluster.

Console

To enable the driver on an existing cluster:

  1. Visit the Google Kubernetes Engine menu in the Cloud Console.

    Visit the Google Kubernetes Engine menu

  2. Click the cluster's Edit button, which looks like a pencil.

  3. Expand Add-ons.

  4. From the Compute Engine persistent disk CSI Driver dropdown, select Enabled.

  5. Click Save.

Disabling Compute Engine persistent disk CSI Driver

To disable the Compute Engine persistent disk CSI Driver, use gcloud or the Google Cloud Console.

gcloud

To disable the driver on an existing cluster, run the following command:

gcloud beta container clusters update cluster-name \
--update-addons=GcePersistentDiskCsiDriver=DISABLED

Replace cluster-name with the name of the existing cluster.

Console

To enable the driver on an existing cluster:

  1. Visit the Google Kubernetes Engine menu in the Cloud Console.

    Visit the Google Kubernetes Engine menu

  2. Click the cluster's Edit button, which looks like a pencil.

  3. Expand Add-ons.

  4. From the Compute Engine persistent disk CSI Driver dropdown, select Disabled.

  5. Click Save.

Using Compute Engine persistent disk CSI Driver

The following sections describe the typical process for using a Kubernetes volume backed by a CSI driver in GKE.

Create a StorageClass

Once you enable the Compute Engine persistent disk CSI Driver, GKE automatically installs a StorageClass for it. The StorageClass name is standard-rwo. Some older cluster versions, however, might have one of the following names:

  • singlewriter-standard
  • standard-singlewriter

You can find the name of your installed StorageClass by running the following command:

kubectl get sc

You can also install a different StorageClass that uses the Compute Engine persistent disk CSI Driver by adding pd.csi.storage.gke.io in the provisioner field.

For example, you could create a StorageClass using the following file named pd-example-class.yaml:

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: pd-example
provisioner: pd.csi.storage.gke.io
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true
parameters:
  type: pd-ssd

After creating the pd-example-class.yaml file, run the following command:

kubectl create -f pd-example-class.yaml

Create a PersistentVolumeClaim

You can create a PersistentVolumeClaim that references the Compute Engine persistent disk CSI Driver's StorageClass. The following file, named pvc-example.yaml, uses the pre-installed storage class standard-rwo:

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: podpvc
spec:
  accessModes:
  - ReadWriteOnce
  storageClassName: standard-rwo
  resources:
    requests:
      storage: 6Gi

After creating the PersistentVolumeClaim manifest, run the following command:

kubectl create -f pvc-example.yaml

In the pre-installed StorageClass (standard-rwo) volumeBindingMode is set to WaitForFirstConsumer. When volumeBindingMode is set to WaitForFirstConsumer, the PersistentVolume is not provisioned until a Pod referencing the PersistentVolumeClaim is scheduled. If volumeBindingMode in the StorageClass is set to Immediate (or it's omitted), a persistent-disk- backed PersistentVolume is provisioned after the PersistentVolumeClaim is created.

Create a Pod that consumes the volume

When using Pods with PersistentVolumes, we recommend you use a workload controller (such as a Deployment or StatefulSet). While you would not typically use a standalone Pod, the following example uses one for simplicity.

The following example consumes the volume you created in the previous section:

apiVersion: v1
kind: Pod
metadata:
  name: web-server
spec:
  containers:
   - name: web-server
     image: nginx
     volumeMounts:
       - mountPath: /var/lib/www/html
         name: mypvc
  volumes:
   - name: mypvc
     persistentVolumeClaim:
       claimName: podpvc
       readOnly: false

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