Use an EFS resource

The Elastic File System (EFS) is the underlying AWS mechanism for providing storage (disk space) to your cluster. A PersistentVolume is a cluster resource that makes EFS storage available to your workloads and ensures that it persists even when no workloads are connected to it. This topic describes how a workload can access a PersistentVolume with a PersistentVolumeClaim.

GKE on AWS supports static provisioning of PersistentVolumes for all supported Kubernetes versions. For clusters at Kubernetes version 1.24 or later, GKE on AWS also supports dynamic provisioning. To use dynamic provisioning, your cluster administrator must configure it. To learn how, see configure a PersistentVolume.

Create a PersistentVolumeClaim

Choose the appropriate tab below depending on whether you want your workload to connect to a statically or dynamically-provisioned persistent volume.

Static

These instructions assume that your cluster administrator has already provisioned at least one PersistentVolume. To access this PersistentVolume and use its underlying EFS with your workloads, create a PersistentVolumeClaim.

To create a PersistentVolumeClaim for a statically-provisioned PersistentVolume, copy the following YAML manifest into a file named efs-claim.yaml.

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: CLAIM_NAME
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: "" # Leave as empty string for static provisioning
  resources:
    requests:
      storage: 5Gi

Replace:

  • CLAIM_NAME: a name you choose for your PersistentVolumeClaim to bind to - for example, efs-claim1. Leave blank to bind to the default storage class

  1. Apply the YAML to your cluster.

      kubectl apply -f efs-claim.yaml

    This output confirms the PersistentVolumeClaim's creation.

    persistentvolumeclaim/CLAIM_NAME created

Dynamic

These instructions assume that your cluster administrator has already provisioned at least one StorageClass for dynamic provisioning. To create a dynamically-provisioned PersistentVolume with this StorageClass and use the underlying EFS access point with your workloads, create a PersistentVolumeClaim.

To create a PersistentVolumeClaim, follow these steps. The EFS CSI driver uses this PersistentVolumeClaim with the indicated StorageClass to dynamically provision a PersistentVolume.

  1. Copy the following YAML manifest into a file named efs-claim.yaml.
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: CLAIM_NAME
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: "EFS_STORAGE_CLASS_NAME"
  resources:
    requests:
      storage: 5Gi

Replace:

  • CLAIM_NAME: a name you choose for your PersistentVolumeClaim - for example, efs-claim1
  • EFS_STORAGE_CLASS_NAME: the name of the StorageClass you want your PersistentVolumeClaim to bind to. Leave this field blank to bind to the default storage class

  1. Apply the YAML to your cluster.

      kubectl apply -f efs-claim.yaml

    The output confirms the PersistentVolumeClaim's creation.

    persistentvolumeclaim/CLAIM_NAME created

Create a StatefulSet

After you have created a PersistentVolumeClaim, you can use it in a workload. This section creates a sample StatefulSet that uses a PersistentVolumeClaim. You can also use a PersistentVolumeClaim with other workload types such as Pods and Deployments by referencing the claim in spec.volumes.

To create a StatefulSet that mounts the EFS resource referenced in your PersistentVolumeClaim, perform the following steps.

  1. Copy the following YAML manifest into a file named efs-statefulset.yaml. This example manifest launches an Ubuntu Linux container that mounts your EFS resource at /efs-data. The container writes every five seconds to a file on your EFS resource named out.txt.

    apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: efs-shell
spec:
  selector:
    matchLabels:
      app: test-efs
  serviceName: efs-app
  replicas: 1
  template:
    metadata:
      labels:
        app: test-efs
    spec:
      terminationGracePeriodSeconds: 10
      containers:
      - name: linux
        image: ubuntu:bionic
        command: ["/bin/sh"]
        args: ["-c", "while true; do echo $(date -u) >> /efs-data/out.txt; sleep 5; done"]
        volumeMounts:
        - name: efs-volume
          mountPath: /efs-data
      volumes:
      - name: efs-volume
        persistentVolumeClaim:
          claimName: CLAIM_NAME

    Replace CLAIM_NAME with the name of the PersistentVolumeClaim you specified previously - for example, efs-claim1.

  2. Apply the YAML to your cluster.

     kubectl apply -f efs-statefulset.yaml

    The output confirms the StatefulSet's creation.

    statefulset.apps/efs-shell created

    The StatefulSet might take several minutes to download and launch the container image.

  3. Confirm the StatefulSet's Pod is in Running status with kubectl get pods.

      kubectl get pods -l app=test-efs

    The output includes the name of the Pod and its status. In the following response, the Pod's name is efs-shell-0.

    NAME          READY   STATUS    RESTARTS   AGE
efs-shell-0   1/1     Running   0          1m

  4. After the Pod is in Running status, use kubectl exec to connect to the Pod hosting the StatefulSet.

      kubectl exec -it efs-shell-0 -- bash

    The kubectl command launches a shell on the Pod.

  5. To confirm that your EFS resource is mounted, check the contents of the out.txt file with the tail command.

    tail /efs-data/out.txt

    The output contains recent times in UTC.

  6. Disconnect from the Pod with the exit command.

      exit

    Your shell returns to your local machine.

Clean up

To remove the StatefulSet, use kubectl delete.

  kubectl delete -f efs-statefulset.yaml

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