We were looking for a solution for executing selenium bases scenarios written in behave in parallel to speed up the execution time. Unluckily behave doesn't have this in build like cucumber fortunately we came across https://github.com/hugeinc/behave-parallel in which upstemsync was just couple of weeks old :)
I already had a picture in mind how would the entire step would work so creating a demo project wasn't too difficult.
Check out https://github.com/mubbashir/behave-selenium
Following is screen recoding where I had connected to both nodes via VNC and checks were executed in Parallel on features level
$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 34911106818f selenium/node-firefox-debug:2.47.1 "/opt/bin/entry_point" 2 hours ago Up 2 hours 0.0.0.0:32769->5900/tcp condescending_elion 14971ef95408 selenium/node-firefox-debug:2.47.1 "/opt/bin/entry_point" 2 hours ago Up 2 hours 0.0.0.0:32768->5900/tcp trusting_mahavira 10688bf744d4 selenium/hub:2.47.1 "/opt/bin/entry_point" 3 hours ago Up 3 hours 0.0.0.0:4444->4444/tcp selenium-hub
docker port <container-name|container-id> 5900 docker port 34911106818f #=> 0.0.0.0:49338