Create volume snapshots

This document explains how to create a copy, or snapshot, of a storage volume at a specific point in time for your container application. A volume snapshot lets you bring a volume back to a prior state or provision a new volume.

This document is for developers within the application operator group, who are responsible for creating application workloads for their organization. For more information, see Audiences for GDC air-gapped documentation.

Before you begin

To complete the tasks in this document, you must request the necessary permissions and prepare your environment.

Request IAM roles

You must have specific roles to get the permissions you need to create volume snapshots. The roles you require depend on whether you are working within an organization-scoped shared cluster or project-scoped standard cluster. For more information, see Kubernetes cluster configurations.

Shared cluster roles

To create, delete, edit, or view volume snapshots in a shared cluster, ask your Project IAM Admin to grant you the Namespace Admin (namespace-admin) role. This role is bound to your project namespace.

Standard cluster roles

To create, delete, edit, or view volume snapshots in a standard cluster, ask your Project IAM Admin to grant you the Cluster Developer (cluster-developer) role. This role is bound to your project namespace.

Prepare your environment

To run commands against a Kubernetes cluster using the API, make sure you have the following resources:

  • Locate the Kubernetes cluster name, or ask a member of the platform administrator group what the cluster name is.

  • Sign in and generate the kubeconfig file for the Kubernetes cluster.

  • Use the kubeconfig path of the Kubernetes cluster to replace KUBERNETES_CLUSTER_KUBECONFIG in these instructions.

Take a volume snapshot

To take a snapshot of a PersistentVolumeClaim object, create a VolumeSnapshot object. The system does not guarantee data consistency. Pause the application and flush data before taking a snapshot.

  1. Create a VolumeSnapshot custom resource:

    kubectl --kubeconfig KUBERNETES_CLUSTER_KUBECONFIG \
    --namespace NAMESPACE apply -f - <<EOF
apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshot
metadata:
  name: VOLUME_SNAPSHOT_NAME
spec:
  source:
    persistentVolumeClaimName: PVC_NAME
EOF

    Replace the following:

    • KUBERNETES_CLUSTER_KUBECONFIG: the kubeconfig file for the cluster.

    • NAMESPACE: the namespace in which to create the volume snapshot. For shared clusters, this must be a project namespace. For standard clusters, it can be any namespace.

    • VOLUME_SNAPSHOT_NAME: the VolumeSnapshot object name.

    • PVC_NAME: the name of the PVC for which you are creating a snapshot.

  2. The snapshot operation is complete when the .status.readyToUse field becomes true. You can use the following command to check the status:

      kubectl --kubeconfig KUBERNETES_CLUSTER_KUBECONFIG get volumesnapshot \
    -o custom-columns='NAME:.metadata.name,READY:.status.readyToUse'

  3. Update the PVC manifest with the volume snapshot specified as a data source:

    kubectl --kubeconfig KUBERNETES_CLUSTER_KUBECONFIG \
    --namespace NAMESPACE apply -f - <<EOF
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: PVC_NAME
spec:
  dataSource:
    name: VOLUME_SNAPSHOT_NAME
    kind: VolumeSnapshot
    apiGroup: snapshot.storage.k8s.io
  storageClassName: standard-rwo
  accessModes:
    - ReadWriteOnce
resources:
  requests:
    storage: 10Gi
EOF

    Replace the following:

    • KUBERNETES_CLUSTER_KUBECONFIG: the kubeconfig file for the cluster.

    • NAMESPACE: the namespace in which the PVC resource exists. For shared clusters, this must be a project namespace. For standard clusters, it can be any namespace.

    • PVC_NAME: the name of the PVC for which you are creating a snapshot.

    • VOLUME_SNAPSHOT_NAME: the name of the volume snapshot.

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