How to Change Default kernel in jupyter notebook

I am using ipython 6.4.0 on ubuntu 20.04 and using jupyter kernelspec list , I found, there are 2 kernels :

1. practice_applied_ai
2. python3

When I open any .ipynb file, it directly opens in “python3” but I want to open it in “practice_applied_ai” because I created virtual environment practice_applied_ai and only in this kernel I can import Tensorflow 2.2.0 for my work.
My question is, Is there any way to change my default kernel without removing any kernel ?

[ankitgupta1729]

Sir, Thank you so much for the help 😃

If you’re opening existing notebook files, the kernel-name is part of the file’s metadata - so it will use that kernel.

Yes, I checked now. I thought I can open other files which are used with different kernels in the kernel “practice_applied_ai”. I did not know that kernel name is part of file’s metadata. Now, I understood it.

[kevin-bates]

Sounds like you’re doing the right thing.

when I open any file from that, it opens it in python3 kernel

If you’re opening existing notebook files, the kernel-name is part of the file’s metadata - so it will use that kernel. I’m not sure how to trigger the use of the “default kernel” other than from the REST API I described previously. The Notebook and Lab UIs require the user to select a kernel when creating notebooks and that selection is from the list of available kernels - which includes the default kernel (among others). You might have the wrong idea about when the default kernel name is used.

Another way to determine your configuration of a default kernel is working is to visit this URL via a web browser: http://localhost:8888/api/kernelspecs. This is much easier than issuing a POST request as I described previously.

The response to visiting that URL is the set of kernelspec information. The first portion of which is the name of the default kernel. Again, you’ll see here the the ‘ir’ kernel is (now) configured as my default:

{
  "default": "ir",
  "kernelspecs": {
    "python3": {
      "name": "python3",
      "spec": {
        "argv": [
          "/opt/anaconda3/envs/elyra-dev/bin/python",
          "-m",
          "ipykernel_launcher",
          "-f",
          "{connection_file}"
        ],
        "env": {},
        "display_name": "Python 3",
        "language": "python",
        "interrupt_mode": "signal",
        "metadata": {}
      },
      "resources": {
        "logo-64x64": "/kernelspecs/python3/logo-64x64.png",
        "logo-32x32": "/kernelspecs/python3/logo-32x32.png"
      }
    },
    "ir": {
      "name": "ir",
      "spec": {
        "argv": [
          "/Library/Frameworks/R.framework/Resources/bin/R",
          "--slave",
          "-e",
          "IRkernel::main()",
          "--args",
          "{connection_file}"
        ],
        "env": {},
        "display_name": "R",
        "language": "R",
        "interrupt_mode": "signal",
        "metadata": {}
      },
      "resources": {
        "kernel.js": "/kernelspecs/ir/kernel.js",
        "logo-64x64": "/kernelspecs/ir/logo-64x64.png"
      }
    }
  }
}