When I used an X11 desktop, I could run graphical applications in docker containers by sharing the $DISPLAY variable and /tmp/X11-unix directory. For example:

docker run -ti -e DISPLAY=$DISPLAY -v /tmp/.X11-unix:/tmp/.X11-unix some:ubuntu xclock

Now, I'm on Fedora 25 running Wayland, so there is no X11 infrastructure to share with the container. How can I launch a graphical application in the container, and have it show up on my desktop? Is there some way to tie in XWayland?

  • Not sure how to answer your question the right way (I've never done it before) but on my system the unix domain socket used by Wayland is at /run/user/1000/wayland-0 for my personal desktop. – Bratchley Dec 14 '16 at 16:26
up vote 8 down vote accepted

As you say you are running Fedora 25 with Wayland, I assume you are using Gnome-Wayland desktop.

Gnome-Wayland runs Xwayland to support X applications. You can share Xwayland access like you did before with Xorg.

Your example command misses XAUTHORITY, and you don't mention xhost. You need one of this ways to allow X applications in docker to access Xwayland (or any X). As all this is not related to Wayland, I refer to How can you run GUI applications in docker container? on how to run X applications in docker.

As for short, two solutions with xhost:

  1. Allow your local user access via xhost: xhost +SI:localuser:$(id -un) and create a similar user with docker run option: --user=$(id -u):$(id -g)
  2. Discouraged: Allow root access to X with xhost +SI:localuser:root

Related Pitfall: X normally uses shared memory (X extension MIT-SHM). Docker containers are isolated and cannot access shared memory. That can lead to rendering glitches and RAM access failures. You can avoid that with docker run option --ipc=host. That impacts container isolation as it disables IPC namespacing. Compare: https://github.com/jessfraz/dockerfiles/issues/359

To run Wayland applications in docker without X, you need a running wayland compositor like Gnome-Wayland or Weston. You have to share the Wayland socket. You find it in XDG_RUNTIME_DIR and its name is stored in WAYLAND_DISPLAY. As XDG_RUNTIME_DIR only allows access for its owner, you need the same user in container as on host. Example:

docker run -e XDG_RUNTIME_DIR=/tmp \
           --user=$(id -u):$(id -g) \
           imagename waylandapplication

QT5 applications also need -e QT_QPA_PLATFORM=wayland and must be started with imagename dbus-launch waylandapplication

x11docker for X and Wayland applications in docker is an all in one solution. It also cares about preserving container isolation (that gets lost if simply sharing host X display as in your example).

  • What if I'm unsure if the app I want to run is X or Wayland? Is there anything generic I can pass so it can automatically determine if XWayland is needed or not? – Oxwivi Mar 25 at 12:50
  • @Oxwivi You can combine both ways; take the Wayland setup example and add -e DISPLAY=$DISPLAY -v /tmp/.X11-unix:/tmp/.X11-unix. Also execute xhost +SI:localuser:$(id -un). Pitfall without generic solution: QT5 on wayland mostly needs dbus-launch while GTK3 on Wayland often fails with dbus-launch. x11docker provides this combination with x11docker --hostdisplay --hostwayland. Most applications will support and prefer X if available. To prefer Wayland set -e XDG_SESSION_TYPE=wayland. – mviereck Mar 25 at 14:46
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    @ShN It is possible to run Weston as a client in another Wayland compositor. Inside this client Weston you can run Xwayland with X applications. With x11docker: x11docker --weston-xwayland imagename application – mviereck Mar 27 at 16:12
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    @Shn Also you can run Xwayland directly as a Wayland client: Xwayland :20 & sleep 3 && docker run -e DISPLAY=:20 -v /tmp/.X11-unix:/tmp/.X11-unix imagename application. Xwayland will cover the whole display; you can move it around with <Super><LeftMouseButton>. With x11docker: x11docker --xwayland imagename application. – mviereck Mar 27 at 16:28

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