Docker Registry(v2) Manifest Cleanup

About

This script will search your registry and delete all manifests that do not have any tags associated. Deletion happens through the docker-registry API and should, therefore, be reasonably safe. After running this, you should do a garbage collect in the registry to free up the disk space.

Why does this happen?

Docker images can be pulled both via image:tag and via image@digest. Because of this, if you overwrite an image:tag with a different one (e.g., pushing nightly to whateverimage:latest) you will still be able to pull the OLD versions of that tag by using image@digest. This functionality means the registry garbage collect cannot remove an image because a reference still exists.

Isn't this a bug?

Not really, some people use image@digest to make sure they pull the correct image to be certain that they get the right code in their project. Docker DAB files are one example of this.

There is; however, some work being done to make an API endpoint to find these 'hidden' manifests quickly. This work is being done in docker/distribution#2170 and docker/distribution#2169.

A feature request to be able to explicitly garbage collect untagged manifests is proposed in docker/distribution#1844.

This repo is meant as a workaround until we have the necessary tooling in Docker and registry to handle this without 3rd party tools.

Usage

Replace the <path-to-registry> and <registry-url> in the below commands. See the example below if needed.

To do a dry-run, add -e DRY_RUN=true.

After running this, you should do a garbage collect in the registry to free up the disk space.

For a normal http registry:

docker run -it -v <path-to-registry>:/registry -e REGISTRY_URL=<registry-url> mortensrasmussen/docker-registry-manifest-cleanup

For an https registry with self-signed certificates:

docker run -it -v <path-to-registry>:/registry -e REGISTRY_URL=<registry-url> -e CURL_INSECURE=true mortensrasmussen/docker-registry-manifest-cleanup

Dry-run

docker run -it -v <path-to-registry>:/registry -e REGISTRY_URL=<registry-url> -e DRY_RUN=true mortensrasmussen/docker-registry-manifest-cleanup

Example:

docker run -it -v /home/someuser/registry:/registry -e REGISTRY_URL=http://192.168.50.87:5000 mortensrasmussen/docker-registry-manifest-cleanup

License

This project is distributed under Apache License, Version 2.0.

Copyright © 2017 Morten Steen Rasmussen