If you’ve installed Docker with the default settings on Debian, it will be storing Docker images, containers and volumes in /var/lib/docker, which will be an issue if you have /var on its own (usually small) partition.
After using Docker for a while you may start to run out of space on the /var partition, at which point you’ll need to either add more space to that partition or relocate it to somewhere with more space.
Here are the steps to change the directory even after you’ve created Docker containers etc.
Note, you don’t need to edit docker.service or init.d files, as it will read the change from the .json file mentioned below.
Steps
- Edit
/etc/docker/daemon.json(if it doesn’t exist, create it) - Add the following
{ "data-root": "/new/path/to/docker-data" } - Stop docker
sudo systemctl stop docker
- Check docker has been stopped
ps aux | grep -i docker | grep -v grep
- Copy the files to the new location
Optionally you could run this insidescreenif you have a large amount of data or unreliable ssh connection.sudo rsync -axPS /var/lib/docker/ /new/path/to/docker-data
Options explanation, check out the man page for more info
-a, --archive archive mode; equals -rlptgoD (no -H,-A,-X)
-x, --one-file-system don't cross filesystem boundaries
-P show progress during transfer-S, --sparse handle sparse files efficiently
- Start Docker back up
sudo systemctl start docker
- Check Docker has started up using the new location
docker info | grep 'Docker Root Dir'
- Check everything has started up that should be running
docker ps
Leave both copies on the server for a few days to make sure no issues arise, then feel free to delete it.
sudo rm -r /var/lib/docker
Documentation / sources
Official docs https://docs.docker.com/engine/admin/systemd/
Docker GitHub issue item https://github.com/docker/docker/issues/3127
Blog post inspired by linuxconfig
Tested and working on Debian Stretch (9.3) with Docker Docker version 17.12.0-ce