How to remove kernel from list?

[scruel]

(base) scruel@scruel:~$ jupyter kernelspec remove root
[RemoveKernelSpec] WARNING | Config option `kernel_spec_manager_class` not recognized by `RemoveKernelSpec`.
Couldn't find kernel spec(s): root

(base) scruel@scruel:~$ jupyter kernelspec remove base
[RemoveKernelSpec] WARNING | Config option `kernel_spec_manager_class` not recognized by `RemoveKernelSpec`.
Couldn't find kernel spec(s): base

(base) scruel@scruel:~$ jupyter kernelspec remove conda-root-py
[RemoveKernelSpec] WARNING | Config option `kernel_spec_manager_class` not recognized by `RemoveKernelSpec`.
Couldn't find kernel spec(s): conda-root-py

(base) scruel@scruel:~$ python -m nb_conda_kernels remove base
[RemoveKernelSpec] WARNING | Config option `kernel_spec_manager_class` not recognized by `RemoveKernelSpec`.
[RemoveKernelSpec] [nb_conda_kernels] enabled, 4 kernels found
Couldn't find kernel spec(s): base

(base) scruel@scruel:~$ python -m nb_conda_kernels remove root
[RemoveKernelSpec] WARNING | Config option `kernel_spec_manager_class` not recognized by `RemoveKernelSpec`.
[RemoveKernelSpec] [nb_conda_kernels] enabled, 4 kernels found
Couldn't find kernel spec(s): root

(base) scruel@scruel:~$ python -m nb_conda_kernels remove conda_root_py
[RemoveKernelSpec] WARNING | Config option `kernel_spec_manager_class` not recognized by `RemoveKernelSpec`.
[RemoveKernelSpec] [nb_conda_kernels] enabled, 4 kernels found
Couldn't find kernel spec(s): conda_root_py

(base) scruel@scruel:~$ python -m nb_conda_kernels remove test
[RemoveKernelSpec] WARNING | Config option `kernel_spec_manager_class` not recognized by `RemoveKernelSpec`.
[RemoveKernelSpec] [nb_conda_kernels] enabled, 4 kernels found
Couldn't find kernel spec(s): test

(base) scruel@scruel:~$ jupyter kernelspec remove test
[RemoveKernelSpec] WARNING | Config option `kernel_spec_manager_class` not recognized by `RemoveKernelSpec`.
Couldn't find kernel spec(s): test

(base) scruel@scruel:~$ python -m nb_conda_kernels remove conda-env-test-py
[RemoveKernelSpec] WARNING | Config option `kernel_spec_manager_class` not recognized by `RemoveKernelSpec`.
[RemoveKernelSpec] [nb_conda_kernels] enabled, 3 kernels found
Kernel specs to remove:
  conda-env-test-py     /home/scruel/mambaforge/envs/test/share/jupyter/kernels/python3
Remove 1 kernel specs [y/N]: y
Traceback (most recent call last):
  File "/home/scruel/mambaforge/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/home/scruel/mambaforge/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/home/scruel/mambaforge/lib/python3.10/site-packages/nb_conda_kernels/__main__.py", line 7, in <module>
    KernelSpecApp.launch_instance()
  File "/home/scruel/mambaforge/lib/python3.10/site-packages/traitlets/config/application.py", line 982, in launch_instance
    app.start()
  File "/home/scruel/mambaforge/lib/python3.10/site-packages/jupyter_client/kernelspecapp.py", line 324, in start
    return self.subapp.start()
  File "/home/scruel/mambaforge/lib/python3.10/site-packages/jupyter_client/kernelspecapp.py", line 215, in start
    path = self.kernel_spec_manager.remove_kernel_spec(kernel_name)
  File "/home/scruel/mambaforge/lib/python3.10/site-packages/nb_conda_kernels/manager.py", line 386, in remove_kernel_spec
    spec_dir = specs[name]
KeyError: 'conda-env-test-py'

(base) scruel@scruel:~$ python -m nb_conda_kernels list
[ListKernelSpecs] WARNING | Config option `kernel_spec_manager_class` not recognized by `ListKernelSpecs`.
[ListKernelSpecs] [nb_conda_kernels] enabled, 4 kernels found
Available kernels:
  conda-env-d2l-py        /home/scruel/mambaforge/envs/d2l/share/jupyter/kernels/python3
  conda-env-pytorch-py    /home/scruel/mambaforge/envs/pytorch/share/jupyter/kernels/python3
  conda-env-test-py       /home/scruel/mambaforge/envs/test/share/jupyter/kernels/python3
  python3                 /home/scruel/mambaforge/share/jupyter/kernels/python3
  conda-root-py           /home/scruel/mambaforge/share/jupyter/kernels/python3
(base) scruel@scruel:~$ jupyter kernelspec list
[ListKernelSpecs] WARNING | Config option `kernel_spec_manager_class` not recognized by `ListKernelSpecs`.
Available kernels:
  python3    /home/scruel/mambaforge/share/jupyter/kernels/python3

I want to remove conda-root-py, python3 and conda-env-test-py (test env) from kernel list, tried many ways, however, it not works.
Also, how to add them back? (remove should not delete any files)

[scruel]

By the way, will it be possible to remove “Python 3 (ipykenel)” from the list? I don't want to let users use base env at all.

[mahendrapaipuri]

@scruel There is a env_filter config parameter to filter conda envs based on regular expression. There is also whitelist that you can define in the config parameter.

[mcg1969]

Thank you for the input, @mahendrapaipuri , that's correct.