If you are a Linux user, you probably know the hassle of rebooting your system after installing a kernel update. This can sometimes be inconvenient, especially if you are running a server or a critical application that needs to be always available. Fortunately, there is a way to apply kernel
I can see this being useful for NixOS. It’s still a glimmer in the postman’s eye, and we’re WAITING for systemd src to come with certain options to make the attaching and reattaching of systemd easier.
But I could easily see
nixpkgs
implement functions that allownixos-rebuild switch
to use either live patching method, or even implementing one specifically for NixOS.This would be twice as neat, because
switch
is already magical in how it shifts from one system to another. If you could then also live patch the kernel? It just adds another super power.Sadly, I could not. Live patching requires extensive knowledge of the previous system state and that is the antithesis to NixOS where any system state is fully independent of any other possible system state.
nixos-rebuild switch
isn’t very magical at all once you understand this principle.Live patching is also not really something you want to use or use frequently. It’s more intended for “this super critical box can only be taken down next Saturday but there’s a fix for a 0-day in the kernel today that we need ASAP”. If it’s at all possible to simply reboot, simply reboot (or kexec).