Volume Snapshots

Storage / Guide 74 of 103 / Advanced

• Kubernetes1.36.4
• Cluster4 nodes
• Runtimecontainerd 2.2.6
• CNICalico v3.32.1
• TimeAbout 35 min

The snapshot API is snapshot.storage.k8s.io/v1, served by CRDs from the external-snapshotter project rather than by core Kubernetes.

• Snapshot APIsnapshot.storage.k8s.io/v1
• Driverhostpath.csi.k8s.io

This guide includes

Use this when you need a point-in-time copy of a volume, and when you have to explain why that copy is not a backup. This matters because the snapshot API mirrors the volume API exactly - and like the volume, it lives and dies inside the same cluster.

• recognising the three snapshot objects as the same shape as PVC, PV and StorageClass
• taking a VolumeSnapshot that names a snapshot class and a source claim
• restoring into a new claim and proving the copy holds the data as of the snapshot
• reading the content object's deletion policy, which is why a snapshot can outlive its source
• saying plainly why none of this amounts to a backup

Before you start

• The CSI drivers guide, which installs the snapshot CRDs and controller used here.
• The PersistentVolumes and claims guide.
• A CSI driver whose deployment includes the external-snapshotter sidecar.

1. 1

   Three objects, in a shape you already know

2. 2

   Take a snapshot

3. 3

   Restore, and see that it is a copy

4. 4

   The snapshot outlives its source

5. 5

   Why this is not a backup

Official sources

• Volume snapshots
• Volume snapshot classes
• CSI snapshot support
• external-snapshotter
• Velero