jamcswain/drbd-docker repository overview

⁠drbd-docker

This container builds and inserts the DRBD module into the host kernel.

⁠Requirements

Unfortunately, due to DRBD's kernel module, this image only run on kernels where Ubuntu Bionic, the OS for the base image, can pull down kernel headers (such as k3os).

⁠Image

An up-to date Docker image can be found on Dockerhub at jmcswain/drbd-docker. To pull:

docker pull jmcswain/drbd-docker

⁠Usage

⁠Kernel Modules

A custom kernel module is installed when the container boots up. In order for this process to work, the underlying system either already needs to have DRBD installed or the host modules directory needs to be shared with the container. Specifically, the /lib/modules directory needs to be mapped to /lib/modules in the container. This can be done with the -v /lib/modules:/lib/modules flag in docker run.

⁠Within Kubernetes

The kubernetes/ subdirectory gives an example of this image as an initContainer for a linstor-satellite DaemonSet.

⁠Notes on k3os

K3os uses Ubuntu's mainline kernel for packaging, and recent releases provide the kernel headers (in /usr/src/), meaning the only real requirement would be DKMS and the DRBD module source, but the scope of this image is more generic than k3os.

I will personally be deploying and using this image on bleeding edge k3os releases.

⁠Permissions

When running a container based upon this image, the following system capabilities are necessary:

• SYS_MODULE

⁠Example docker run command

docker run -it --rm --cap-add sys_module \
       -v /lib/modules:/lib/modules \
       jmcswain/drbd-docker