...
- update jupyterhub_config
- service jupyterhub stop: use "docker ps" you can find docker container is still running
- docker stop <main CONTAINER ID> : browser stops running.
- service jupyterhub start (don't use /home/ubuntu/start_jupyterhub.sh)
you cannot set ACCESS-CONTROL as '*', it is not working. https://github.com/jupyterhub/jupyterhub/issues/1087