It is possible to apply kernel updates to an Ubuntu system without rebooting the server using a feature called "live patching". Live patching allows you to apply certain types of kernel patches without interrupting the running system, by loading the patches into the kernel at runtime.
To use live patching on Ubuntu, you will need to install the Canonical Livepatch Service, which is a tool provided by Canonical (the company behind Ubuntu) that enables live patching on Ubuntu systems.
To install the Canonical Livepatch Service on an Ubuntu system, follow these steps:
Make sure you have a valid Ubuntu Single Sign-On (SSO) account. If you don't have one, you can create one at https://login.ubuntu.com/.
Install the snapd package, which is required to use the Canonical Livepatch Service. You can install it by running the following command:
sudo apt install snapd
sudo snap install canonical-livepatch
sudo canonical-livepatch enable
Once the Canonical Livepatch Service is installed and connected to your Ubuntu SSO account, it will automatically check for and apply available kernel patches without requiring a reboot. You can check the status of the live patching process by running the canonical-livepatch status command.
Note that not all types of kernel patches can be applied using live patching, and some patches may still require a reboot to fully apply. Live patching is primarily intended for applying security patches and other critical updates that need to be applied quickly without interrupting the running system. For more information about live patching and the Canonical Livepatch Service, you can refer to the official documentation at https://docs.ubuntu.com/core/en/livepatch/.