Search
⌃K

Manage kernels

The kernel is the execution environment that performs computation for a notebook's code in a particular programming language, such as Python or R. This article will cover how to manage kernels.
A notebook needs to be connected to a kernel in order to execute Python or R code.

Start a kernel

To manually start a kernel:
  1. 1.
    Go to a notebook.
  2. 2.
    Click Kernel from the notebook menu bar.
  3. 3.
    Select
    Launch from the menu.
  4. 4.
    When complete, the status will show as Connected in the footer.
A kernel will start automatically when a new notebook is created or a user executes a cell in an existing notebook.
Managing kernels

Restart a kernel

You can restart the kernel using the menu option or the button in the footer:
Menu
Footer
  1. 1.
    Go to the notebook.
  2. 2.
    Click Kernel from the notebook menu bar.
  3. 3.
    Select
    Restart from the menu.
  4. 4.
    When complete, the status will show as Connected in the footer.
Click on the
Restart button in the footer page.
When complete, the status will show as Connected in the footer.
To clear current outputs while restarting, select
Restart Kernel & Clear All Outputs.

Change kernel

To switch between Python and R kernels:
  1. 1.
    Go to a notebook.
  2. 2.
    Click Kernel from the notebook menu bar.
  3. 3.
    Select
    Change kernel from the menu.
  4. 4.
    Pick the desired kernel.

Interrupt a Kernel

At times, with long executing code cells, you may want to interrupt the kernel.
To interrupt a running cell:
Menu
Cell
Footer
  1. 1.
    Go to the notebook.
  2. 2.
    Click Kernel from the notebook menu bar.
  3. 3.
    Select
    Interrupt from the menu.
  4. 4.
    When complete, the status will show as Not Connected in the footer.
  1. 1.
    Select
    Interrupt from the cell status bar. This will only appear when the cell is executing.
  2. 2.
    When complete, the status will show as Not Connected in the footer.
  1. 1.
    Select
    Interrupt from the notebook footer. This will only appear when the notebook is executing.
  2. 2.
    When complete, the status will show as Not Connected in the footer.

Shutdown a Kernel

To shutdown the kernel:
  1. 1.
    Go to a notebook.
  2. 2.
    Click Kernel from the notebook menu bar.
  3. 3.
    Select
    Shutdown from the menu.
  4. 4.
    When complete, the status will show as Not Connected in the footer.

Learn more

Kernels can be customized to have different compute profiles based on user needs. To learn more about how to configure memory and CPU profiles for kernels, please read: