Run NoMachine's client in a container

Download and install NoMachine's proprietary code in a Debian 11 container. You can then mount your X11 socket in that container and run the NoMachine client, if you want to connect to a NoMachine server.

First, build the container image. The following instructions work for Docker and Podman alike:

git clone https://github.com/apyrgio/docker-nomachine
cd docker-nomachine/
docker build -f Dockerfile -t nx

Then, run the NoMachine client (nxplayer) in the container.

docker run --rm -e DISPLAY=${DISPLAY?} -v /tmp/.X11-unix:/tmp/.X11-unix:ro \
    -e XAUTHORITY=${XAUTHORITY?} -v ${XAUTHORITY?}:${XAUTHORITY}  \ # Remove if no XAUTHORITY file
    nx /usr/NX/bin/nxplayer

Caveats:

For compatibility reasons, in Wayland systems this will use XWayland (less secure)
The configuration is amnesiac, meaning that connections are lost after the container exits.
Rebuilding the container image always pulls the .deb file, in order to verify that the step is cached.