Jupyterhub on Centos7: ruamel.yaml error (Jupyter Notebook works)

JupyterHub
1

Hi all

After installing JupyterHub via python3 pip, I get this error:

(base) root@host [~/.jupyter]# jupyterhub -hTraceback (most recent call last): File “/usr/local/bin/jupyterhub”, line 5, in
from jupyterhub.app import main
File “/usr/local/lib/python3.6/site-packages/jupyterhub/app.py”, line 64, in
from jupyter_telemetry.eventlog import EventLog
File “/usr/local/lib/python3.6/site-packages/jupyter_telemetry/init.py”, line 6, in
from .eventlog import EventLog # noqa
File “/usr/local/lib/python3.6/site-packages/jupyter_telemetry/eventlog.py”, line 10, in
from ruamel.yaml import YAML
ImportError: cannot import name ‘YAML’

I do have ruamel.yaml installed in /usr/lib64/python3.6/site-packages (version 0.13.14), and this Centos7 system works perfectly with a Notebook server.

Why is Jupyterhub not working and/or not seeing/searching installed modules properly?

2

You’ve mentioned two different Python environments, one under /usr/local and one under /usr/lib64. There’s no guarantee that packages from these two environments can be combined. To avoid these types of problems you can create an independent virtualenv instead and install everything in that.

3

Hi, thanks for your feedback, I thought the same but actually that system works perfectly with everything else. Looking into another forum for another software, I came to the fact that the problem lies into ruamel.yaml package, that gives problems quite often apparently.

The solution posted was to install instead a patched version of the same package, called ruamel_yaml, always via pip, and that solved the problem.