Jupyter notebook 内核无效

（以python2为例，python3以此类推）
参考：https://blog.csdn.net/linhai1028/article/details/79544537
列出可用的kernel，报错如下

root@a64b41a98807 ~# jupyter kernelspec list
[ListKernelSpecs] WARNING | Error loading kernelspec 'python2'
Traceback (most recent call last):
  File "/root/downloa/lib/python2.7/site-packages/jupyter_client/kernelspec.py", line 258, in get_all_specs
    spec = self._get_kernel_spec_by_name(kname, resource_dir)
  File "/root/downloa/lib/python2.7/site-packages/jupyter_client/kernelspec.py", line 201, in _get_kernel_spec_by_name
    return self.kernel_spec_class.from_resource_dir(resource_dir)
  File "/root/downloa/lib/python2.7/site-packages/jupyter_client/kernelspec.py", line 47, in from_resource_dir
    kernel_dict = json.load(f)
  File "/root/downloa/lib/python2.7/json/__init__.py", line 291, in load
    **kw)
  File "/root/downloa/lib/python2.7/json/__init__.py", line 339, in loads
    return _default_decoder.decode(s)
  File "/root/downloa/lib/python2.7/json/decoder.py", line 364, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/root/downloa/lib/python2.7/json/decoder.py", line 380, in raw_decode
    obj, end = self.scan_once(s, idx)
ValueError: Invalid control character at: line 5 column 19 (char 85)
No kernels available

先将坏掉的kernel删掉

root@a64b41a98807 ~# jupyter kernelspec remove python2
Kernel specs to remove:
  python2 /root/downloa/share/jupyter/kernels/python2
Remove 1 kernel specs [y/N]: y
[RemoveKernelSpec] Removed /root/downloa/share/jupyter/kernels/python2

重新安装

root@a64b41a98807 ~# python2 -m ipykernel install
Installed kernelspec python2 in /usr/local/share/jupyter/kernels/python2

若是还未下载ipykernel

root@a64b41a98807 ~# pip2 install ipykernel