If you do heavy development with docker without a cleanup strategy soon your disk will fill at the time you really have to ship something out ASAP because production is on-fire but you cannot because docker refused to let you do anything with it.
When we run a process in our computers, once that process is done, everything is tear down together with it. Container is how many of us operating our infrastructure nowaday.
Everything run on a container, aim to have one process per container. When the process is done, the container is exit. But it won’t cleanup after itself. It leave behind its legacy.
Docker stuff that accumulate
You need to keep an eyes on these
- stopped containers
- volume
- images
- network
If you have enough space, you may not worry too much about disk space but the network is an important one. By default, Docker uses bridge network, and it has a limit of 31 networks. When reaching that limit, you will see this message:
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This happens if you’re a heavy docker-compose user which create a network
per project. You can workaround by setting a customi --subnet such as:
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But anyway, the point of this article is to clean up
Cleanup with docker
Cleanup stopped containers
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This will find all container in exited status and output their ID once per line so we can feed it to other shell command.
We use docker rm -v to also delete any anonymous volume(volumes without
an explicitly name).
Cleanup volumes
Above comand should remove volumes that are associated with that container. If you manually create volumes and want to delete any volumes that are not being used:
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Cleanup images
Docker images are generally safe to delete all. We can fetch them on-demand when we need to. Usually after a image cleaning, build time is longer because docker daemon has to spend time downloading image again
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Here we used --force to delete images even if a container are using
that. We can always fetch them again later
Cleanup networks
Easy peasy. We can delete anything, it will be re-created on-demand later on
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Cleanup with docker-compose
If you spin up containers using docker-compose, we have an easy way to cleanup resources associated with thart particular compose file.
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Unfortunately this command won’t remove anonymous volume so you have to deal with them.
One command to rule them all
docker is ephemeral and we can always re-fetch the image, re-seed our database for development, or this is just a CI system then we can delete verything
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