KernelSpecManager.ensure_native_kernel=False doesn't work and default jupyter kernel still appears

[venkatesh-g-patil]

Hi Team,

Reference issue: jupyter-server/jupyter_server#1461 (comment)

We are currently using jupyterhub=5.3.0, jupyter_client=7.4.9 and wanted to know if there is any fix to avoid having default jupyter kernel appearing on jupyterhub with the libraries related to jupyter python environment. We do not want any kernel to be exposed to some of the users and right now have to create a dummy kernel with python3 name since by default jupyter kernel appears for all users.

Please let us know if this issue will be solved in any of the next releases. Also if there is a work around such as a config change which can completely remove the default kernel from appearing please let us know. Thank you.

Regards,
Venkatesh Patil

[minrk]

Have you removed share/jupyter/kernels/python3? The python3 (aka 'native') kernelspec is installed as part of installing ipykernel. The ensure_native_kernel behavior is for making sure python3 is available even if no kernelspec is installed for ipykernel, which is an increasingly rare situation, and indicates an at least partially broken install. In the vast majority of installations, this option does nothing because the case of ipykernel being installed but no python3 kernelspec being found doesn't happen if ipykernel is properly installed.

If you want to specify what kernelspecs are available in configuration, you can:

c.KernelSpecManager.allowed_kernelspecs = ["kernel1", "kernel2", "..."]

Then whatever other kernelspecs are installed won't be available.

[venkatesh-g-patil]

Hi @minrk thank you for the response. After removing the /use/local/share/jupyter/kernels/python3 there is a kernel that appears on jupyterhub with the name python3 and it points to the juoyter python environment. I don't want to expose any kernel to a set of users. Any suggestions regarding this will be very helpful.

[minrk]

As I mentioned above, using allowed_kernelspecs should give you complete control over what's available, regardless of what's installed.

[venkatesh-g-patil]

Thank you @minrk this is working when tested. I wanted to check in there anything available similar to 'NotebookApp.terminals_enabled=False' which is used to disable terminal, if we want to disable the 'Markdown File', 'Text File', Filebrowser options on launcher for a set of users and not globally. Something that we can specify in the config file. Thanks

[minrk]

Those are mostly UI questions, and probably best directed at the jupyterlab repo or forum