This documentation is for the most recent version of Anthos clusters on AWS, released on August 4. See the Release notes for more information. For documentation on the previous generation of Anthos clusters on AWS, see Previous generation.

Use StorageClasses with your workloads

Anthos clusters 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 Anthos clusters 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 set provisions a General Purpose SSD volumes (gp2) volume using the default Anthos clusters 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 Anthos clusters 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

You can create additional StorageClasses for EBS volumes or use Container Storage Interface (CSI) Drivers.

  1. Choose if you are using an EBS volume or another CSI driver.

    EBS Volume

    You can 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 Anthos clusters 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
    

    EBS Volume on Windows node pools

    For workloads running Windows node pools create a custom StorageClass that specifies an EBS volume type, the NTFS file system type, and other parameters. You can find additional StorageClass parameters on the Anthos clusters 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
    parameters:
      csi.storage.k8s.io/fstype: ntfs
    

    Replace CLASS_NAME with the name of your new StorageClass.

    CSI Driver

    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.

  2. Apply the YAML to your cluster.

    kubectl apply -f my-custom-class.yaml
    

Create a PersistentVolumeClaim with a custom StorageClass

  1. 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

Anthos clusters 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:

  1. 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"}}}'
    
  2. 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 Throughput Optimized HDD EBS volumes formatted with the XFS file system.

    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:
      csi.storage.k8s.io/fsType: xfs
      type: st1
    
  3. Apply the new custom class to your cluster.

    kubectl apply -f my-custom-class.yaml
    

After applying this manifest, Anthos clusters 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: k8s.gcr.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

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