Mostly the configurabilty of clearml-session and how it was designed. Jupyterhub spawns a process at :8000 which we had to port foreward by hand, but spawning new docker containers using jupyterhub.Dockerspawner and connecting them to the correct network (the hub should talk to them without --network host ) seem too difficult or even impossible.

Oh, and there was no JupyterHub stdout in the console output on clearml server, it shows the jupyterlab's output by default