How to automatically cleanup your docker registry instance

Quick install

This quick-install script works if you are running the docker registry image using docker-compose and the service in docker-compose.yml is called registry. I recommend to use our example on how to install the docker registry for Gitlab (not yet available).

Run this in the directory where docker-compose.yml is located!

wget -qO- https://techoverflow.net/scripts/install-registry-autocleanup.sh | sudo bash

Need an explanation (or not using docker-compose)?

Docker registry instances will store every version of every image you push to them, so especially if you are in a continous integration environment you might want to do periodic cleanups that delete all images without a tag.

The command to do that is

registry garbage-collect /etc/docker/registry/config.yml -m

You can use a systemd service like

[Unit]
Description=registry-gc

[Service]
Type=oneshot
ExecStart=/usr/local/bin/docker-compose exec -T registry bin/registry garbage-collect /etc/docker/registry/config.yml -m
WorkingDirectory=/opt/my-registry

and a timer like

[Unit]
Description=registry-gc

[Timer]
OnCalendar=daily
Persistent=true

[Install]
WantedBy=timers.target

to run the command daily. You need to adjust both the WorkingDirectory and the exact docker-compose exec command to suit your needs.

Copy both files to /etc/systemd/system and enable the timer using

sudo systemctl enable registry-gc.timer

and you can run it manually at any time using

sudo systemctl start registry-gc.service