How to move the default /var/lib/docker to another directory for Docker on Linux?

Stop the server: sudo systemctl stop docker
Create/edit the configuration at /etc/docker/daemon.json, for example: { "data-root": "/new/path/docker-data-root" }
Copy your data there:

sudo cp -axT /var/lib/docker /new/path/docker-data-root

(if the target docker-data-root directory already exists, make sure you don’t accidentally copy into a docker subdirectory).

sudo systemctl start docker

sudo docker images