KubeVirt Datamover Plugin

OADP Velero plugin for KubeVirt incremental backup and restore.

Overview

This repository contains Velero BackupItemAction (BIA) and RestoreItemAction (RIA) plugins that enable KubeVirt VirtualMachine backups using qcow2 incremental snapshots instead of traditional CSI snapshots.

These plugins work in conjunction with the KubeVirt Datamover Controller to provide:

• True block-level Changed Block Tracking (CBT) instead of full volume scans
• Faster incremental backups using QEMU/libvirt native capabilities
• VM-aware backup operations (as opposed to treating disks as generic PVCs)

How It Works

┌─────────────────────────────────────────────────────────────────────────────┐
│                           Velero Backup Flow                                │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                             │
│  1. Velero triggers backup                                                  │
│           │                                                                 │
│           ▼                                                                 │
│  2. VirtualMachine BIA Plugin                                               │
│      • Checks VM has ChangedBlockTracking enabled                           │
│      • Validates volume policies (action: "kubevirt")                       │
│      • Creates DataUpload with SnapshotType: "kubevirt"                     │
│           │                                                                 │
│           ▼                                                                 │
│  3. KubeVirt Datamover Controller (separate component)                      │
│      • Reconciles DataUpload                                                │
│      • Creates VirtualMachineBackup CR                                      │
│      • Copies qcow2 files to BSL                                            │
│           │                                                                 │
│           ▼                                                                 │
│  4. Backup completes with incremental qcow2 data in object storage          │
│                                                                             │
└─────────────────────────────────────────────────────────────────────────────┘

Plugins

VirtualMachine BackupItemAction

Handles VirtualMachine resources during backup:

• Validates that Changed Block Tracking is enabled on the VM
• Checks that the VM is running (offline backup not supported in initial release)
• Evaluates volume policies to determine if KubeVirt datamover should be used
• Creates a DataUpload CR with:
  • Spec.SnapshotType: "kubevirt"
  • Spec.DataMover: "kubevirt"
• Adds DataUploadNameAnnotation to the VirtualMachine
• Returns an async operation ID for progress tracking

PersistentVolumeClaim BackupItemAction

Handles PersistentVolumeClaim resources during backup:

• Determines whether a PVC belongs to a VM that is eligible for kubevirt datamover (same preconditions as the VirtualMachine BackupItemAction)
• Stamps the AnnotationVMName annotation on the PVC so the restore-side PersistentVolumeClaim RestoreItemAction can recognize it later
• Does not create any CR itself — the VM BackupItemAction owns DataUpload creation

PersistentVolumeClaim RestoreItemAction

Handles PersistentVolumeClaim resources during restore:

• Recognizes PVCs backed up via the kubevirt datamover, using the AnnotationVMName annotation stamped on the PVC by the PVC BackupItemAction
• Creates a DataDownload CR with Spec.DataMover: "kubevirt" to trigger the KubeVirt Datamover Controller's restore path (qcow2-to-raw conversion)
• Returns an async operation ID for progress tracking, mirroring the backup-side DataUpload flow
• Honors Restore.Spec.NamespaceMapping: Spec.TargetVolume.Namespace is set to the remapped namespace, while Spec.SourceNamespace stays the original, pre-remap namespace
• Operates at the PVC level (not VM level), so multi-disk VMs are handled naturally: one DataDownload per PVC, no special-casing required

VirtualMachineBackup/VirtualMachineBackupTracker RestoreItemAction

Prevents restoration of backup-related CRs:

• Discards VirtualMachineBackup resources on restore
• Discards VirtualMachineBackupTracker resources on restore
• Prevents accidental re-triggering of backup operations

Prerequisites

• OADP 1.5+ with Velero 1.15+
• KubeVirt with Changed Block Tracking support
• KubeVirt Datamover Controller deployed in the cluster
• SnapshotMoveData: true on backups

Integration with OADP

The plugin is deployed as an init container in the Velero deployment. Add the following to your OADP DataProtectionApplication CR:

apiVersion: oadp.openshift.io/v1alpha1
kind: DataProtectionApplication
metadata:
  name: velero-dpa
spec:
  configuration:
    velero:
      defaultPlugins:
        - openshift
        - kubevirt
        - kubevirt-datamover  # Enable KubeVirt datamover plugins
  # ... other configuration

Building

# Build locally
make build-local

# Build with Podman or Docker
make all

# Build container image
make container

# Run tests
make test

# Clean build artifacts
make clean

Project Structure

kubevirt-datamover-plugin/
├── kubevirt-datamover-plugin/
│   ├── main.go                 # Plugin registration
│   └── clients/                # Kubernetes client factory
│       └── clients.go
├── Dockerfile
├── Makefile
├── go.mod
└── go.sum