Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

Docker images are saved in /var/lib/docker. You can link the directory to another place to save images elsewhere. Another way is to change the configuration file of Docker. For example, you can add the following into /etc/default/docker to save docker images into /mnt (instead of the default location).

DOCKER_OPTS="-dns 8.8.8.8 -dns 8.8.4.4 -g /mnt"

1. symbolic link

2. bind mount (check Specifying a default Docker storage directory by using bind mount for more details)

3. Add the options into the file /etc/docker/daemon.json.

   {
       "data-root": "/new/data/root/path"
   }
   

Restart Docker after whichever approach you take.

sudo systemctl restart docker

References

https://forums.docker.com/t/how-do-i-change-the-docker-image-installation-directory/1169

https://www.ibm.com/support/knowledgecenter/SSBS6K_3.1.1/installing/docker_dir.html

https://stackoverflow.com/questions/19234831/where-are-docker-images-stored-on-the-host-machine