By default, Docker places the containers under /mnt/doc/docker/containers which you can get from docker info command as “Docker Root Directory”. Normally this may cost, make your server running out of space while you are creating more and more containers. To avoid such a case, we can change the default installation path to preferable one or separate directory. Will see how to change the docker default installation directory.
root@ubuntu:~# docker info
Sometimes, if you are using much containers or your server space is limited, you may run out od space. You can keep check the server space using df command.
root@ubuntu:~# df -h Filesystem Size Used Avail Use% Mounted on udev 2.4G 4.0K 2.4G 1% /dev tmpfs 496M 52M 444M 11% /run /dev/mapper/ubuntu--vg-root 30G 28G 2G 98% / tmpfs 2.5G 188K 2.5G 1% /dev/shm tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs 2.5G 0 2.5G 0% /sys/fs/cgroup /dev/sda1 472M 462M 0 100% /boot /dev/sda1 200G 8G 192G 4% /mnt/doc tmpfs 496M 0 496M 0% /run/user/111 tmpfs 496M 0 496M 0% /run/user/1000
The / directory is almost full. We can fix by adding a new virtual disk (in case you are running it under VM), partioning it and mounting it under /mnt/doc. You can see the status of current disk space, and where I have a new disk /dev/sdb1 added and mounted under /mnt/doc/. Now I can use /mnt/doc/docker folder to store all my containers.
Step 1: Stop the docker service
root@ubuntu:~# /etc/init.d/docker stop
Step 2: Change the Directory
- Ubuntu/Debian: edit your /etc/default/docker file with the -g option: DOCKER_OPTS=”-dns 8.8.8.8 -dns 8.8.4.4 -g /mnt/doc”
- Fedora/Centos: edit /etc/sysconfig/docker, and add the -g option in the other_args variable: ex. other_args=”-g /mnt/doc/”. If there’s more than one option, make sure you enclose them in ” “. After a restart, (service docker restart) Docker should use the new directory.
All I did is added a line -g /mnt/doc/docker -p /var/run/docker.pid to the OPTIONS.
Caution – These steps depend on your current /mnt/doc/docker being an actual directory (not a symlink to another location).
1) Stop docker: service docker stop. Verify no docker process is running ps faux
2) Double check docker really isn’t running. Take a look at the current docker directory: ls /mnt/doc/docker/
2a) Make a backup – tar -zcC /var/lib docker > /mnt/doc/var_lib_docker-backup-$(date +%s).tar.gz
3) Move the /mnt/doc/docker directory to your new partition: mv /mnt/doc/docker /mnt/doc/docker
4) Make a symlink: ln -s /mnt/doc/docker /mnt/doc/docker
5) Take a peek at the directory structure to make sure it looks like it did before the mv: ls /mnt/doc/docker/ (note the trailing slash to resolve the symlink)
6) Start docker back up service docker start
7) restart your containers
Step 3: Restart the docker service:
root@ubuntu:~# service docker start root@ubuntu:~# docker info Containers: 0 Running: 0 Paused: 0 Stopped: 0 Images: 0 Server Version: 1.12.2 Storage Driver: aufs Root Dir: /mnt/doc/docker/aufs Backing Filesystem: extfs Dirs: 363 Dirperm1 Supported: true Logging Driver: json-file Cgroup Driver: cgroupfs Plugins: Volume: local Network: null host bridge overlay Swarm: inactive Runtimes: runc Default Runtime: runc Security Options: apparmor seccomp Kernel Version: 4.4.0-47-generic Operating System: Ubuntu 16.04.1 LTS OSType: linux Architecture: x86_64 CPUs: 4 Total Memory: 4.835 GiB Name: ubuntu Docker Root Dir: /mnt/doc/docker Debug Mode (client): false Debug Mode (server): false Registry: https://index.docker.io/v1/ WARNING: No swap limit support Insecure Registries: 127.0.0.0/8
Now the Data file shows /mnt/doc/docker as the destination container storage location.
Also, you will notice that there will be a repo created as soon as you restart the docker service
root@ubuntu:~# ls -lrt total 34 drwx——. 2 root root 4096 Apr 25 07:24 tmp drwx——. 4 root root 4096 Apr 25 07:24 devicemapper drwx——. 2 root root 4096 Apr 25 07:24 containers drwx——. 2 root root 4096 Apr 25 07:24 graph drwx——. 2 root root 4096 Apr 25 07:24 volumes drwx——. 2 root root 4096 Apr 25 07:24 trust -rw——-. 1 root root 19 Apr 25 07:24 repositories-devicemapper -rw-r–r–. 1 root root 5120 Apr 25 07:24 linkgraph.db drwx——. 2 root root 4096 Apr 25 07:24 init drwx——. 3 root root 4096 Apr 25 07:24 execdriver
