Jupyterhub cannot start server - 500 error - jupyter

Question

I am trying to run jupyter hub for multiuser mode. I installed jupyterhub from PIP.
[root#ip-of-machine hadoop]# echo $PATH
/usr/local/bin/jupyterhub-singleuser:/usr/local/bin/jupyterhub:/sbin:/bin:/usr/sbin:/usr/bin:/opt/aws/bin
When I tun jupyterhub I get an error saying
500 : Internal Server Error
Failed to start your server. Please contact admin.
I ran it as
[root#ip-of-machine hadoop]# /usr/local/bin/jupyterhub -f ./jupyterhub/jupyterhub_config.py --no-ssl
The logs contain
[I 2016-05-03 17:13:09.406 JupyterHub spawner:465] Spawning jupyterhub-singleuser --user=jupyter --port=40770 --cookie-name=jupyter-hub-token-jupyter --base-url=/user/jupyter --hub-host= --hub-prefix=/hub/ --hub-api-url=http://127.0.0.1:8081/hub/api --ip=127.0.0.1
[E 2016-05-03 17:13:09.433 JupyterHub user:237] Unhandled error starting jupyter's server: [Errno 2] No such file or directory: 'jupyterhub-singleuser'
But there is singleuser in path. I explicitly added it to path and exported.
Any clues? Thanks.

Answer 1

PATH should contain a list of directories containing executables that should be found, not the executables themselves.
So instead of
/usr/local/bin/jupyterhub-singleuser:/usr/local/bin/jupyterhub:/sbin:/bin:/usr/sbin:/usr/bin:/opt/aws/bin
your PATH should be:
/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/opt/aws/bin
which should find both jupyterhub and jupyterhub-singleuser.