An example of one possible approach for running X11 GUI applications from within a Docker container. This example is NOT focused on security, but instead on minimizing the amount of dependencies on the host machine. Docker Compose is needed for running the example script as is, but it is not mandatory for following this approach.

$ bin/xeyes.sh

Before launching the GUI application we generate a custom .Xauthority file with a FamilyWild connection family. This will allow any connection access to the current X server session. Special care should be taken to avoid leaking this file to untrusted parties. Afterwards we launch the application passing along the current DISPLAY environment variable. We also mount /tmp/.X11-unix/ and our custom .Xauthority file as read-only volumes.