Velero Backup Controller Visualization

Interactive visualization of how Velero processes backup operations internally. Three views covering the controller chain, volume protection decision tree, and concurrent activity timeline.

Open the visualization

Built from reading the Velero source at vmware-tanzu/velero@b74f8c9.

Views

Controller Flow

Swim-lane diagram showing how a Backup CR moves between Velero's four controllers:

• Queue Controller — concurrency limits, namespace conflict detection, FIFO ordering
• Backup Controller — validation, backup engine, item processing
• Operations Controller — polls async plugin operations (CSI data movers)
• Finalizer Controller — processes async results, writes terminal phase

Each controller's lane shows its specific actions. Handoff banners appear between lanes when the backup transitions from one controller to another via phase writes.

Simulation paths: Happy Path, Validation Failure, Partial Failure, Fatal Error, Kopia FSB, CSI Snapshot, CSI + Data Mover, Native Snapshot.

Volume Decision Tree

Step-by-step wizard that walks through the volume protection decision logic. Answer questions about your configuration and it shows the exact code path:

• Volume policy resolution (ResourcePolicy ConfigMap)
• DefaultVolumesToFsBackup opt-in vs opt-out
• Pod annotation handling
• CSI snapshot with/without data mover
• Native cloud snapshots (AWS EBS, GCP PD, Azure Disk)

Five possible outcomes: Kopia FSB, CSI VolumeSnapshot (in-cluster), CSI + Kopia Data Mover, Native Cloud Snapshot, or No Protection.

Timeline

Gantt-style chart showing what runs in parallel during a backup:

• Dependency arrows (red = blocks on, orange = triggers)
• Annotated callouts at key moments (handoffs, blocking points, parallel activities)
• Click any bar to see its dependencies, what triggers it, and what runs alongside it

Scenarios: Happy Path (metadata only), Kopia FSB, CSI Snapshot, CSI + Data Mover, Native Snapshot.

AI-Readable Reference

ARCHITECTURE.md contains the same information as structured prose — the complete controller chain, volume decision tree, dependency graph, and concurrency model. Designed to be consumed by AI agents, used as a CLAUDE.md reference, or read as documentation.

Tech

Three static HTML files, zero dependencies. All styling and logic is inline. Runs from file:// or any static host.

index.html          # Landing page — what is Velero, what the views cover
flow.html           # Controller flow (swim lanes + simulations)
decision-tree.html  # Volume protection wizard
timeline.html       # Concurrent activity Gantt chart
ARCHITECTURE.md     # Machine-readable reference

Source

Based on reading Velero source at commit b74f8c951. Key files traced:

File	What it covers
pkg/controller/backup_queue_controller.go	Queue management, concurrency, namespace conflicts
pkg/controller/backup_controller.go	Validation, runBackup(), phase determination
pkg/controller/backup_operations_controller.go	Async operation polling
pkg/controller/backup_finalizer_controller.go	Finalization, async result processing
pkg/backup/backup.go	Core engine, item collection, block processing
pkg/backup/item_backupper.go	Per-item logic, BIA execution, PV snapshots
pkg/backup/actions/csi/pvc_action.go	CSI VolumeSnapshot, DataUpload creation
pkg/podvolume/backupper.go	PodVolumeBackup creation, Kopia uploader
internal/volumehelper/volume_policy_helper.go	ShouldPerformSnapshot/FSBackup decision logic
internal/resourcepolicies/resource_policies.go	Volume policy matching and actions