Running X11 server inside a container

[hoshsadiq]

I'm curious if it is possible at all to run x11 server and client inside a container. Reason for this is that I'd like to run a pi with nothing but docker and let docker continually pull an updated fully configured image. I know I can (obviously) run server on the pi, but I'm trying to have to avoid as any moving pieces within the pi, and so all the configuration required would be inside the container. Is this possible at all? I've done a lot of searching but have come out blank.

[mviereck]

Do you want the X server to access the hardware?

If you want to use a real Monitor at your pi, you would need Xorg with hardware access. That is possible with a highly privileged container, but I discourage it. If Xorg runs in a container, it might make wrong assumptions on the connected hardware and might damage it.

An invisible X server without hardware access like Xvfb would be no problem. You could remotely access it with xpra, or even run xpra+Xvfb in a container.

A third possibility is Xwayland in container and Wayland compositor Weston on host. See https://github.com/mviereck/dockerfile-x11docker-xwayland

[hoshsadiq]

I think really you answered my question. Was hoping that it would be possible without increased privileges, so I'll try and use the ways you suggested. Thanks for your help!

[mviereck]

Finally x11docker allows to run Xorg in a container.
Since x11docker version 7.1.5-beta-17 this is possible with options --xc --xorg if image x11docker/xserver is provided.
The most important missing key was to share /run/udev/data with the container to allow right hardware detection for Xorg. Other important parts are capability TTY_SYS_CONFIG and devices in /dev/input.
The setup is still experimental. I hope it will work on other machines and setups as well.

The X container needs some advanced privileges, but they are not shared with the GUI container.
Dependencies on host are reduced now; however, X tools like xauth are still used from host.