Increase Docker container size from default 10GB on rhel7

Question

When I launch a container from rhel7.3 image, the default container size is 10GB. I want to increase it to 20GB. I tried the below ways but I had no luck

1) Added "DOCKER_STORAGE_OPTIONS": "--storage-opt dm.basesize=20G" in /etc/docker/daemon.json file. /etc/docker/daemon.json file is not there by default so I had to add it and tried restarting docker. Restart fails with the below error:

"unable to configure the Docker daemon with file /etc/docker/daemon.json: the following directives don't match any configuration option: DOCKER_STORAGE_OPTIONS\n"

2) Added "dm.basesize=20G" parameter while I launch the conatiner

docker run --privileged --storage-opt "dm.basesize=20G" -d IMAGE_ID but it fails to launch with error

"docker: Error response from daemon: Unknown option dm.basesize."

Any help on how I can achieve to launch a container with 20GB instead of the default 10GB? Thanks, Premchand

Answer 1

I changed the storage type to "Overlay" by the following steps

1) Added {"storage-driver": "overlay"} in /etc/docker/daemon.json file. This file was not there in rhel 7.3 so I added it manually.

2) Restarted docker

My issue of increasing the container volume is resolved as each container get total amount of volume available on the host.

Answer 2

Had the same issue as you, after a lot of research i found a simple solution:

1. stop the docker service:

   sudo systemctl stop docker

2. edit your docker service file, located at:

   /usr/lib/systemd/system/docker.service

3. find the execution line:

   ExecStart=/usr/bin/dockerd
   and change it to:
   ExecStart=/usr/bin/dockerd --storage-opt dm.basesize=20G

4. start docker service again:

   sudo systemctl start docker

all done.