run GUI app in docker container from XRDP client - docker

Question

I have two machines,
machine A: system ubuntu 20.04 (DISPLAY :0)
machine B: system windows 10
in machine A, I create a docker container with the following command:
docker run --rm -it -v /tmp/.X11-unix:/tmp/.X11-unix -e DISPLAY=$DISPLAY -v $(pwd):/home/walid/notebooks opencv bash
the docker container has Visual Studio Code installed and OpenCV, I run the following command to go in the container bash:
docker exec -it $containerId bash
inside the container, I go into the folder notebooks and run the following commands:
code . # to launch the visual studio code
result; the visual studio code opens
python read.py # to open a video capture with OpenCV
result; good the video capture opens
now int the machine B; I use the Remote Desktop Connection to machine B, when I go inside the container to open Visual Studio Code nothings happing doesn't open, when I try python read.py I get an error could not connect to display :10.0
I figure out where I was doing it wrong:
(base) adminsst#admins:~$ xhost
access control enabled, only authorized clients can connect
SI:localuser:adminsst
(base) adminsst#admins:~$ sudo su
root#admins:/home/adminsst# xhost
No protocol specified
xhost: unable to open display ":10.0"
whene I was runing the container in the sudo su it doesn't work, but when I sudo docker run .... it works.
but now when I login to another user in the server (machine A) and do the same think it doesn't work anymore and I will get the same error could not connect to display :11.0

Answer 1

SOLUTION 1
here's the solution I did and it works for me:
first if you run the following command in the new user you will get:
walid#admins:~$ xhost
access control enabled, only authorized clients can connect
now run the this one again to have this result:
walid#admins:~$ xhost +local:
non-network local connections being added to access control list
to launch the GUI app you need to pass the new DISPLAY to the container because it will had been changed every time you login to solve this problem just run the following command:
walid#admins:~$ sudo docker exec -it -e DISPLAY=$DISPLAY open bash
that's all now you will be able to launch the GUI app without any problem, but still every time you login you should exect the following command xhost +local: before starting the container, if someone has a solution for that please let me know
SOLUTION 2
see the following url here
xhost +local:`docker inspect --format='{{ .Config.Hostname }}' $containerId`
docker start $containerId
there more useful solutions
--------
Another thing I have faced, that even when I do the above steps, sometimes doesn't work, I simply change the display ID in the docker container to the same as Local machine ID by the following;
first figure out the local machine display ID by
echo $DISPLAY
then in the docker container do the following
$DISPLAY=:ID