I am using Docker 18.09 and I am trying to build some images for my work. The problem is that the images are always inside the root directory, precisely the `/var/lib/docker/overlay2` are in `/var/docker/`. As there isn't enough space in my root directory, so I want to change this default directory to my other disk but none of the solutions I have looked upon the internet have worked for me. 

I have gone through these already but none of them are working:

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

<https://medium.com/@ibrahimgunduz34/how-to-change-docker-data-folder-configuration-33d372669056>

[How to change the docker image installation directory?](https://stackoverflow.com/questions/24309526/how-to-change-the-docker-image-installation-directory)