How to change the default docker image location in a virtual machine

DockerStorage.md

PROBLEM

We ran in to a lot of space issues with storing docker images in Azure cloud VMs. Because by default docker images, layers and containers are stored in the

/var/lib/docker

It is the same with the Amazon AWS as well.

The problem with this is most of the virtual machines have a very limited space in the OS Disk and the space can run out very soon. It is wise to save the docker images and attach your data containers to point a mount volume.

SOLUTION 1

So if you ever run in to space problems. Do the following steps:

1. sudo service docker stop
2. sudo rm -rf /var/lib/docker/
3. sudo service docker start

If you do the above steps, you will be able to reclaim the spaces. But it is not ideal to remove the containers and images frequently.

SOLUTION 2

So i started mounting my images in the data disks instead of OS disks which you can frequently schedule for a backup as well.

1. Stop the Docker service if it is already running

sudo service docker stop

2. Make a back up of the existing docker directory (Change your mount directory-> /mnt/resource)

sudo tar -zcC /var/lib docker > /mnt/resource/var_lib_docker-backup-$(date +%s).tar.gz

3. Move the /var/lib/docker directory to your new partition

sudo mv /var/lib/docker /mnt/pd0/docker

4. Make a symlink to the new mount point

sudo ln -nfs /mnt/resource/docker /var/lib/docker

5. Take a look at the directory to see and verify whether the symbolic link has been created

sudo ls -l /var/lib/docker

6. Start docker service again

sudo service docker start

7. Restart your containers

8. Check the mounted volume size using

df -h

Credits:

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