JupyterHub not passing IP parameter to single user notebook?

[ldi...@zynga.com]

Hey all,

Long time lurker, first time poster - thank you all for the work you do on this awesome environment!

I'm trying to set up a Jupyterlabhub system and I'm running into some issues as of the most recent release.

Specifically, I've:

- Set up a clean virtualenv on one of our EC2 instance and then installed jupyterhub and jupterlab through pip.

- I've generated a config file and tweaked it to default to /lab as its URL

- I launch it with 'sudo jupyterhub --port=8800'

This works great for my personal login credentials, but when anyone else tries to access it they get an error 500 and on the output I get a long error which is best summarised with the following:

[I 2018-02-28 22:20:53.578 JupyterHub spawner:978] Spawning jupyterhub-singleuser --port=55638

<snip: output explaining argument usage of a single-user server>

[C 2018-02-28 22:20:54.458 SingleUserNotebookApp application:90] Bad config encountered during initialization:

[C 2018-02-28 22:20:54.458 SingleUserNotebookApp application:91] The 'ip' trait of a SingleUserNotebookApp instance must be a unicode string, but a value of None <class 'NoneType'> was specified.

I've now tried this directing the system to the vanilla notebook instead of lab, and I'm getting the same behaviour. It reads to me like some weirdness in how the spawner is instantiating the single user notebook but I'm unclear what I can do differently to get this working.

Does anyone else have experience with this or at least have guidance on where I should start digging?

Thanks,

Luke