Host screen turns off when I start X server in docker container

Question

I created docker container with X server inside. I use it for some off-screen OpenGL rendering. This container should work on any system (with or without X server running) and it should use hardware GPU if it exists (so I cannot use xvfb).

When I use this container on server-like system without GUI, everything works perfectly. But when I run the container on Ubuntu 14.04 Desktop, the screen turns off each time I start X server in my container.

I start container with --priviliged so /dev folder is shared with container. I believe it involves some kind of conflict.

Is there a way to start X inside the container such as host X server is still working?

UPDATE:

I see the following in Xorg.0.log:

AIGLX: Suspending AIGLX clients for VT switch
(II) NOUVEAU(0): NVLeaveVT is called.

UPDATE:

Can I use xvfb instead of real Xorg server? Does it support actual hardware GPU rendering?

Parallelize

Sounds like it tries to grab the GPU hardware and is allowed to. This will not end well. – Sentimentalize

Answer 1

I don't think this is going to work - you're effectively trying to use two X servers - the host and the container - and I suspect they are both expecting to have exclusive use of the video card.

What you can do instead is use the X server on the host from the container by bind-mounting the X Server socket. This SO answer explains how: https://mcmap.net/q/46942/-alternatives-to-ssh-x11-forwarding-for-docker-containers

I'm not sure this will help in your particular case, but I don't entirely understand why you need an XServer running in the container at all. I think you should still have access to the GPU with --privileged.

Calmative

It is not convenient to use host X server, because it may not exist. Ideally, I'd want a solution that works on both desktop and server machines. I need X server because I need "display" in OpenGL context initialization: Display* display = XOpenDisplay( displayName ); – Parallelize

Sorry, I have no idea. – Calmative

Answer 2

If you don't mind using CPU for OpenGL, you can set up an X server inside the container with the Xdummy video driver with GLX extensions. But of course you won't be able to see a thing because the video driver is, well, dummy.

If you do want to play with GUIs, try TurboVNC + VirtualGL and use the Xdummy server as the 3D X server.

Reef