Connect two pi’s - one home assistant and one OpenHAB?

I’m trying an interesting experiment here, trying to link two pi’s to each other (pi 3+ with OpenHAB, pi zero with home assistant) so that I can have the best of both systems.

OpenHAB is leaps and bounds ahead with the insteon binding but does not have the ability to start rules based on Apple TV play state like Home Assistant…

I tried tonight to setup MQTT on both and failed miserably. Does anyone have any suggestions for this setup or guidance on MQTT within either system?

how are you trying to do mqtt connection?

I do this but I have One server receiving all events and processing automatons. The others only send events. frontends for all work but only use the one main server frontend normally

OpenHAB will be “in charge”. I need the following functions:
-OpenHAB can see on/off state of “dummy switches” that will be triggered by home assistant based on Apple TV play state
-OpenHAB can see and control the gpio pins of the home assistant (pi zero) - it’s controlling a few relays

I tried to install the built in mqtt broker on both systems but got completely lost and never got either running. Really any guidance will be appreciated - especially from someone who has a similar setup running.

i use a seperate broker running in docker container
use statestream to send mqtt to openhab
use gpio binary switch in HA to create switch and control gpio
you’ll need automation to catch mqtt topic from openhab and control the gpio switc

some people have issue with HA and Gpio control.
if HA not needed may create python scipt to control gpio and send/rcv mqtt commands

Not mqtt based but check this thread for ideas to connect with node red.