Cannot run X apps in a docker container

Question

Hi, I have a Dockerfile which enables me to run X apps.
It works perfectly in Ubuntu, but not in Archlinux:
FROM mascip/archlinux:2014.12.09
# To avoid a bug with the filesystem: https://registry.hub.docker.com/u/base/arch/
RUN sed 's/^CheckSpace/#CheckSpace/g' -i /etc/pacman.conf
# BROWSERS
RUN pacman --noconfirm -S nvidia-libgl && pacman --noconfirm -S leafpad
# NON-ROOT USER
# Replace you uid, gid, and username
RUN pacman --noconfirm -S sudo
RUN export uid=1000 gid=1000 && the_user="abla" && \
the_home="/home/${the_user}" && \
the_capital_user=$(echo $the_user | sed 's/./\U&/') && \
mkdir -p $the_home && \
echo "${the_user}:x:${uid}:${gid}:${the_capital_user},,,:/${the_home}:/bin/bash" >> /etc/passwd && \
echo "${the_user}:x:${uid}:" >> /etc/group && \
echo "${the_user} ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/${the_user} && \
chmod 0440 /etc/sudoers.d/${the_user} && \
chown ${the_user}:${the_user} -R ${the_home}
# Replace username and home
ENV USER abla
ENV HOME /home/abla
WORKDIR /home/abla
USER abla
CMD /usr/bin/leafpad
In order to run it, I do:
$ docker build -t a1 .
$ docker run -ti \
-e DISPLAY -e XAUTHORITY=/tmp/.Xauthority -v /home/user/.Xauthority:/tmp/.Xauthority -v /tmp/.X11-unix:/tmp/.X11-unix \
a1 leafpad
which works in Ubuntu (a Leafpad window opens), but not in Arch where I get:
leafpad: Cannot open display:
PS: I have a similar Docker container which runs leafpad in a Ubuntu container; the problem is exactly the same for that container too.
PPS: the Dockerfile stems from here: http://fabiorehm.com/blog/2014/09/11/ru … th-docker/
Edit: I need to make it work soon. I would appreciate any idea to investigate further. I find X11 magic very confusing.
Last edited by mascip (2015-03-02 14:09:58)

Answer 1

I have tried checking that the Xserver was running with
$ ps aux | grep X
and it wasn't (is that even possible, as things were displaying on my screen?)
So I installed the whole xorg group:
$ sudo pacman -Sy xorg
After that, startx wouldn't start anymore, and I had to upgrade everything:
$ sudo pacman -Syu
which fixed the problem.
Now the X server is running:
$ ps aux | grep X
grep: warning: GREP_OPTIONS is deprecated; please use an alias or script
root 335 0.8 1.0 289376 42688 tty1 Ssl+ 06:46 0:01 /usr/lib/xorg-server/Xorg :0 -seat seat0 -auth /run/lightdm/root/:0 -nolisten tcp vt1 -novtswitch
user 459 0.0 0.2 304648 9980 ? Ssl 06:46 0:00 /usr/bin/lxsession -s LXDE -e LXDE
user 531 0.4 0.6 497908 24460 ? Sl 06:47 0:00 lxpanel --profile LXDE
user 532 0.2 0.8 607376 34960 ? Sl 06:47 0:00 pcmanfm --desktop --profile LXDE
user 944 0.0 0.0 10712 2256 pts/1 S+ 06:49 0:00 grep --color=auto X
but Leafpad still won't be displayed and throws the same error.
Any more ideas?
Last edited by mascip (2015-03-02 08:04:26)