Select which privileged service can access hdmi display


I’m hoping this is not something anyone has asked before— mods, feel free to link to a relevant post if it exists, I could not find one.

I am currently developing a docker-compose services deployment where two of the services are privileged. One service controls robotics hardware, while another one displays information on a screen connected via the HDMI port. For the sake of this discussion, consider the GUI service to be running balenablocks/browser.

When I build and run only the display service, I have no problems displaying the intended GUI on the screen, however, when I include the other privileged robotics hardware service, the screen goes blank.

I’m guessing that I need to somehow specify some configuration in my docker-compose.yaml file to select which service should have access to the monitor. Is this correct? I could potentially also be completely off on this as I’ve never developed a multi-container deployment with monitor access, so any input is welcomed!

For reference, in my actual deployment I’m using the X11 balenablock to run the GUI, as described in this other post: looking for a light X11 server for production ready deployment of GUI app. - #6 by Sylvain42 .

Hey , yes you need to set the display variable in the environment. See the Usage guide of the xserver block

Great thank you @iamsolankiamit . I’m having a new issue now which I will post about on a separate topic. Cheers