--sudouser cannot run GUI applications with sudo

[mviereck]

If running a container with --sudouser, running GUI applications with su or sudo fails with an authentication error.
DISPLAY and XAUTHORITY are set correctly.
Running with --user=root instead works fine.

Workarounds found so far:

• Run with --sudouser --xoverip
• Run with --sudouser --hostnet

A message explaining the workarounds is shown if one uses --sudouser.

I am not exactly sure why it does not work to run GUI applications with sudo, but --user=root works.
X has some sort of dbus authentication next to the classic XAUTHORITY cookie method.
This might explain why --xoverip and --hostnet can be used as a workaround. But this does not explain the different behaviour of sudo vs. --user=root. For that case I would expect to fail --user=root the same way like sudo with --sudouser does.

[hongyi-zhao]

I tried you above suggestion with --home --user=root --sudouser, and meet the following error:

x11docker ERROR: Option --home: Could not create persistent home folder for
  user 'root' on host. Can e.g. happen with option --user.
  Four possibilities to solve issue:
  1.) Run x11docker one time as user 'root'.
  2.) Run x11docker one time as user 'root'.
  3.) Use option --home=DIR with DIR pointing to a writeable folder.
  4.) Use option --home=VOLUME to use a docker volume.

Very strange, in the above message, 1.) and 2.) are completely same.

[mviereck]

Very strange, in the above message, 1.) and 2.) are completely same.

ok, hat looks a bit odd here. It would look different if you would run with another user name, e.g. --user=someoneelse.
However, that is not related to the X authentication issue of this ticket but a special case of --home --user=root.

[hongyi-zhao]

I still can't figure out why x11docker prevent the use of the following two options at the same time:

--home --user=root

[mviereck]

I still can't figure out why x11docker prevent the use of the following two options at the same time:
--home --user=root

This would need access to HOME of root, i.e. folder /root on host. You would need to run x11docker as root to allow this, at least one time to let it create /root/.local/share/x11docker/IMAGENAME. Your regular user werner is not allowed to do this.