Docker Cleanup

/docker-cleanup (admin-only) is docker system df and docker system prune from the dashboard. Unlike everything else in Homerun it is not scoped to containers Homerun created, that's the entire point of a cleanup tool: it can see, and remove, anything on the host's Docker daemon.

The page previews what's actually reclaimable before you commit, unused images, stopped containers, unreferenced volumes, unused networks (excluding Docker's own three defaults and anything still attached), and unused build cache, with the space each category would free. You can then prune each category on its own, or use Quick cleanup → Clean up now, which prunes stopped containers, dangling images, unused networks and build cache together, the same set as docker system prune, and never touches volumes. Every action asks for confirmation first.

• Images prunes only dangling images by default. Tick Include tagged, unused images to remove any image no container uses. The last few images of every service are kept either way, see Revisions and rollback.
• Networks also offers Reclaim orphaned stack networks: the per-stack networks whose stack no longer exists, which Docker's own prune can't see while anything is still attached. A network with containers attached is left alone.

Two things worth knowing:

• Pruning volumes deletes data. An unreferenced Docker-managed volume is one no container currently mounts. A storage volume mounted into a Homerun service is always kept, even while that service is stopped or has no container at all, but a volume another tool created and no container uses is removed.
• Pruning networks can remove the shared homerun network once the last container detaches from it. That's harmless, Homerun recreates it on the next deploy rather than assuming it exists.

A cleanup runs through the same job queue as deploys, and holds the queue while it runs, so it can't delete an image or build cache out from under a deploy in flight.

Image mirror

The Image mirror panel shows how much disk the homerun-mirror registry image scanning copies images into is using, and Clean up mirror garbage-collects it. The same cleanup runs on its own every day at 04:00 (postponed within that hour while a deploy or scan is queued or running), and on demand from the Registry page's own Collect garbage button. It:

1. keeps, per service, the current image:tag, the digest of its last successful deploy and its last two scanned digests. An older kept version whose tag has moved on is re-tagged homerun-keep-<digest> so the next step doesn't sweep it;
2. deletes every other manifest through the registry API, which needs the registry started with REGISTRY_STORAGE_DELETE_ENABLED=true. A mirror created by an older Homerun without it is recreated once, its homerun-mirror-data volume stays;
3. runs registry garbage-collect --delete-untagged inside the container, removes the repositories nothing is left in, and restarts the registry so its in-memory blob cache doesn't claim a deleted layer still exists.

Like the other cleanups it is a queued job that holds the queue, and a deploy that starts while it runs anyway skips the mirror and pulls directly. The job result and the app log record how many manifests were deleted and the bytes reclaimed.