Volume Snapshot Controller

Deprecated

Please note the volume snapshotting feature is now part of the Container Storage Interface API which makes this implementation obsolete. Consider using a CSI driver in case you need volume snapshots.

Status

Pre-alpha

Demo

• SIG PM 06/13/2017

Quick Howto

• Host Path

• AWS EBS

• GCE PD

Docs

• User Guide
• Kubernetes Snapshotting Proposal

Snapshot Volume Plugin Interface

As illustrated in example plugin hostPath

Plugin API

A Volume plugin must provide RegisterPlugin() to return plugin struct, GetPluginName() to return plugin name, and implement the following interface as illustrated in hostPath

import (
	"k8s.io/client-go/pkg/api/v1"

	crdv1 "github.com/kubernetes-incubator/external-storage/snapshot/pkg/apis/crd/v1"
	"github.com/kubernetes-incubator/external-storage/snapshot/pkg/cloudprovider"
)

type VolumePlugin interface {
	// Init inits volume plugin
	Init(cloudprovider.Interface)
	// SnapshotCreate creates a VolumeSnapshot from a PersistentVolumeSpec
	SnapshotCreate(*v1.PersistentVolume, *map[string]string) (*crdv1.VolumeSnapshotDataSource, *[]crdv1.VolumeSnapshotCondition, error)
	// SnapshotDelete deletes a VolumeSnapshot
	// PersistentVolume is provided for volume types, if any, that need PV Spec to delete snapshot
	SnapshotDelete(*crdv1.VolumeSnapshotDataSource, *v1.PersistentVolume) error
	// SnapshotRestore restores (promotes) a volume snapshot into a volume
	SnapshotRestore(*crdv1.VolumeSnapshotData, *v1.PersistentVolumeClaim, string, map[string]string) (*v1.PersistentVolumeSource, map[string]string, error)
	// Describe volume snapshot status.
	// return true if the snapshot is ready
	DescribeSnapshot(snapshotData *crdv1.VolumeSnapshotData) (snapConditions *[]crdv1.VolumeSnapshotCondition, isCompleted bool, err error)
	// FindSnapshot finds a VolumeSnapshot by matching metadata
	FindSnapshot(tags *map[string]string) (*crdv1.VolumeSnapshotDataSource, *[]crdv1.VolumeSnapshotCondition, error)
	// VolumeDelete deletes a PV
	// TODO in the future pass kubernetes client for certain volumes (e.g. rbd) so they can access storage class to retrieve secret
	VolumeDelete(pv *v1.PersistentVolume) error
}

Volume Snapshot Data Source Spec

Each volume must also provide a Snapshot Data Source Spec and add to VolumeSnapshotDataSource, then declare support in GetSupportedVolumeFromPVC by returning the exact name as returned by the plugin's GetPluginName()

Invocation

The plugins are added to Snapshot controller cmd pkg.