This documentation is for the current version of GKE on AWS, released in November 2021. See the Release notes for more information.

Use StorageClasses with your workloads

GKE on AWS automatically deploys the Container Storage Interface (CSI) Amazon Elastic Block Store (EBS) and Amazon Elastic File Store (EFS).

The EBS CSI Driver and EFS CSI Driver versions are tied to an GKE on AWS Kubernetes version. The driver version is typically the latest available when a GKE version is released. When the cluster is upgraded, the drivers update automatically.

Use the default StorageClass

Creating a PersistentVolumeClaim without the field spec.storageClassName provisions a General Purpose SSD volumes (gp2) volume using the default GKE on AWS EBS CSI Driver StorageClass.

The following YAML creates a PersistentVolumeClaim (PVC) named mypvc with a size of 30 gibibytes.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mypvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 30Gi

Use a different preinstalled StorageClass

The GKE on AWS EBS CSI Driver also includes the premium-rwo StorageClass, which provisions higher-throughput Provisioned IOPS SSD volumes (io1) volumes.

You can use it by specifying it in the spec.storageClassName of the PVC.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mypvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 30Gi
  storageClassName: premium-rwo

Use a custom StorageClass

If neither the default nor the premium-rwo StorageClass meets your needs, you can create additional StorageClasses for EBS volumes or use Container Storage Interface (CSI) Drivers.

Choose if you are using an EBS volume or another CSI driver.
EBS Volume
This tab describes how to create your own custom StorageClass that specifies an EBS volume type, file system type, and other parameters. You can find additional StorageClass parameters on the GKE on AWS EBS CSI Driver GitHub page.

To configure a custom StorageClass, copy the following YAML manifest into a file named my-custom-class.yaml.
```
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: CLASS_NAME
provisioner: ebs.csi.aws.com
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer
```
Replace CLASS_NAME with the name of your new StorageClass.

For example, the following YAML creates a new StorageClass that provisions Throughput Optimized HDD EBS volumes formatted with the XFS file system.
```
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: my-custom-class
provisioner: ebs.csi.aws.com
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer
parameters:
  csi.storage.k8s.io/fsType: xfs
  type: st1
```
Custom EFS StorageClass
This tab describes how to create a custom StorageClass for the EFS CSI Driver provisioner. See Use an EFS resource for a list of the prerequisites for this StorageClass. The EFS CSI Driver page lists additional StorageClass parameters beyond those in following manifest.

Copy the following YAML manifest into a file named my-custom-class.yaml.
```
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: <var>EFS_STORAGE_CLASS_NAME</var>
provisioner: efs.csi.aws.com
mountOptions:
  - tls
parameters:
  provisioningMode: efs-ap
  fileSystemId: EFS_ID
  directoryPerms: "700"
```
Replace:
- EFS_STORAGE_CLASS_NAME with the name of the StorageClass.
- EFS_ID with your EFS file system ID - for example, fs-12345678a.
CSI Driver
Note: This is an example. Check your CSI driver's documentation for required parameters.

You can specify a different CSI driver in the provisioner field.

To create a StorageClass with another CSI driver, you can use the example YAML below.
```
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: CLASS_NAME
provisioner: CSI_DRIVER_NAME
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer
parameters:
  ...
```
Replace the following:
- CSI_DRIVER_NAME with the name of the CSI driver—for example,csi.example.com
- CLASS_NAME with the name of the StorageClass—for example, my-custom-class
Configure the sub-fields under parameters according to your CSI driver.
Apply the YAML to your cluster.
```
kubectl apply -f my-custom-class.yaml
```

Create a PersistentVolumeClaim with a custom StorageClass

Once a custom StorageClass is created, you can specify it in a PVC. The example below creates a PVC named my-pvc that references the StorageClass my-custom-class.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: my-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 30Gi
  storageClassName: my-custom-class

Set the default StorageClass

GKE on AWS uses a default StorageClass called standard-rwo that provisions gp2 EBS volumes. You can change the default to another StorageClass.

To change the default StorageClass:

Update the is-default-class annotation for the standard-rwo StorageClass with kubectl patch.

kubectl patch storageclass standard-rwo -p \
'{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"false"}}}'

Create a new StorageClass that has the annotation storageclass.kubernetes.io/is-default-class: true.

The following example StorageClass uses the ebs.csi.aws.com driver. To install another storage driver, see Install additional CSI drivers.

Copy the following YAML into a file named my-custom-class.yaml.

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: CLASS_NAME
  annotations:
    storageclass.kubernetes.io/is-default-class: true
provisioner: ebs.csi.aws.com
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer
parameters:
  type: EBS_VOLUME_TYPE

Replace the following:

EBS_VOLUME_TYPE: the AWS EBS volume type that the StorageClass creates.
CLASS_NAME with the name of your new StorageClass

For example, the following YAML creates a new default StorageClass that provisions General Purpose SSD volumes (gp3).

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: my-custom-default-class
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: ebs.csi.aws.com
allowVolumeExpansion: true
volumeBindingMode: WaitForFirstConsumer
parameters:
  type: gp3

Apply the new custom class to your cluster.
```
kubectl apply -f my-custom-class.yaml
```

After applying this manifest, GKE on AWS uses the my-custom-default-class StorageClass for new storage requests.

Reference the StorageClass in a StatefulSet

To use your new StorageClass, you must reference it in a StatefulSet's volumeClaimTemplates.

When you reference a StorageClass in a StatefulSet's volumeClaimTemplates specification, Kubernetes provides stable storage using PersistentVolumes (PVs). Kubernetes calls the provisioner defined in the StorageClass to create a new storage volume. After the volume is provisioned, Kubernetes automatically creates a PV.

The following StatefulSet references the my-custom-class StorageClass and provisions a 1 gibibyte volume:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: registry.k8s.io/nginx-slim:0.8
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates: # This is the specification in which you reference the StorageClass
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi
      storageClassName: my-custom-class # This field references the existing StorageClass

What's next

Learn about Persistent volumes and dynamic provisioning in GKE.
Install additional CSI drivers on your GKE on AWS.
Deploy your first workload with the Quickstart.