Unable to get jupyter-fs to show up in JupyterHub

[chippey]

Describe the bug
After installing jupyter-fs via conda into a conda env that runs JupyterHub, various .json files configured fail to get any jupyter-fs tab to show up, and it shows as a greyed out extension in a jupyter server instance. Error log from JupyterHub shows:

/srv/jupyterhub/condaenv/jhub-env/lib/python3.13/site-packages/jupyterfs/extension.py:40: UserWarning: Misconfiguration of MetaManager. Please add:

"ServerApp": {
  "contents_manager_class": "jupyterfs.metamanager.MetaManager"
}

to your Notebook Server config.
  warnings.warn(_mm_config_warning_msg)
[I 2025-07-29 16:38:46.278 ServerApp] jupyterfs.extension | extension was successfully loaded.

despite the json config chunk existing in multiple server config .json files

The conda install creates a jupyter-fs.json in the conda env's jupyter server config folder, ie in: /srv/jupyterhub/condaenv/jhub-env/etc/jupyter/jupyter_server_config.d

After a fresh install, this file includes:

  "ServerApp": {
    "contents_manager_class": "jupyterfs.metamanager.MetaManager",
    "jpserver_extensions": {
      "jupyterfs.extension": true
    }
  },
}

Side note: other extensions installed via conda put their config .jsons in this folder jupyter_server_config.d as well, and are fully functional (ie jupytergis, jupyterlab_nvdashboard, jupyterlab_git).

I've tried also making a jupyter_server_config.json as described in the README on the jupyter-fs github page, and put it in multiple places returned from jupyter --paths:

config:
    /srv/jupyterhub/condaenv/jhub-env/etc/jupyter
    /usr/local/etc/jupyter
    /etc/jupyter

but with no success.

To Reproduce
Steps to reproduce the behavior:

1. Create a conda env
2. Install JupyterHub into the conda env
3. Install jupyter-fs into the conda env
4. See error

Expected behavior
I would expect jupyter-fs to function after the conda install, with the configs as described by the README documentation

Desktop (please complete the following information):

• OS: Rocky Linux 9
• Conda: 25.5.1
• JupyterHub: 5.3
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

[timkpaine]

Does this issue help? #112

[chippey]

No, that appears to reference an issue with the old NotebookApp, which JupyterHub and server haven' used in a long time. The error log I posted shows that it's the ServerApp that's emitting the error (next to the DateTime stamp).

[chippey]

Should I just assume jupyter-fs is incompatible with JupyterHub?

[timkpaine]

Should I just assume jupyter-fs is incompatible with JupyterHub?

you can assume whatever you like. Your instance is not using jupyter-fs as the contents manager, you'll need to follow the jupyterhub documentation for configuring user-specific stuff. There are a bunch of different options depending on your versions of various jupyter dependencies but this is one file/way (it might alternatively be jupyter_notebook_config.py, jupyter_lab_config.py, jupyter_server_config.py, jupyter_notebook_config.json, or jupyter_lab_config.json depending on your setup). The JupyterHub Documentation has some notes about these same options.

[timkpaine]

This might also be due to #324 if used without SSL, will do a release shortly

[dometto]

I ran into the same issue, with the following config dirs:

$ jupyter --paths
config:
    /home/myuser/.jupyter
    /usr/local/jupyterhub/etc/jupyter
    /usr/local/etc/jupyter
    /etc/jupyter
$ ls /usr/local/jupyterhub/etc/jupyter
jupyter_notebook_config.d  jupyter_server_config.d  jupyter_server_config.json  nbconfig

I found out the following:

1. The extension does not show up when I put the jupyterfs config in /usr/local/jupyterhub/etc/jupyter/jupyter_server_config.d/jupyter_fs.json
2. The extension does not show up when I put the jupyterfs config file in /usr/local/jupyterhub/etc/jupyter/jupyter_server_config.d/jupyter_server_config.json
3. The extension does show up when I put the jupyterfs config in /usr/local/jupyterhub/etc/jupyter/jupyter_server_config.json

So it appears that the extension only works when the config is placed in a file literally called jupyter_server_config.json, and is not included from the jupyter_server_config.d directory --- which other extensions installed into my JupyterHub (e.g. the jupyter-git extension) do use.

Since this does not behave the way other extensions do, I would suggest this should perhaps be considered a bug?

[timkpaine]

All of the mechanics of loading those files happen outside this library. So the question is what is Jupyter server doing, and how is Jupyter server determining which files are valid sources of the contents manager override. There is nothing we can change in this library to change the Jupyter server resolution order or mechanics, all we can do is change the docs and potentially change where we install files.