Can you run GUI applications in a Docker container?

Question

How can you run GUI applications in a Docker container?

Are there any images that set up vncserver or something so that you can - for example - add an e

Answer 1

Xauthority becomes an issue with newer systems. I can either discard any protection with xhost + before running my docker containers, or I can pass in a well prepared Xauthority file. Typical Xauthority files are hostname specific. With docker, each container can have a different host name (set with docker run -h), but even setting the hostname of the container identical to the host system did not help in my case. xeyes (I like this example) simply would ignore the magic cookie and pass no credentials to the server. Hence we get an error message 'No protocol specified Cannot open display'

The Xauthority file can be written in a way so that the hostname does not matter. We need to set the Authentication Family to 'FamilyWild'. I am not sure, if xauth has a proper command line for this, so here is an example that combines xauth and sed to do that. We need to change the first 16 bits of the nlist output. The value of FamilyWild is 65535 or 0xffff.

docker build -t xeyes - << __EOF__
FROM debian
RUN apt-get update
RUN apt-get install -qqy x11-apps
ENV DISPLAY :0
CMD xeyes
__EOF__
XSOCK=/tmp/.X11-unix
XAUTH=/tmp/.docker.xauth
xauth nlist :0 | sed -e 's/^..../ffff/' | xauth -f $XAUTH nmerge -
docker run -ti -v $XSOCK:$XSOCK -v $XAUTH:$XAUTH -e XAUTHORITY=$XAUTH xeyes