stacker512 wrote:GeoffF100 wrote:If the Linux Kernel is updated a reboot is required. That can be avoided in some cases by using Live Patch, but I believe that you have to pay Canonical for that service.
My experience is that a kernel update doesn't require you to reboot then and there - you continue to use your existing kernel image and modules until the next reboot. If you require any of the kernel updates (a specific bug fix or a feature) to be active, then sure, you would reboot. Otherwise it's going to be enabled on next boot by the simple fact that when you boot up, the kernel image is loaded up and the relevant modules are loaded.
(edit: you do have kexec, which allows you to load and boot a kernel image from an already running kernel image, but I've never tried it and not sure how many of the popular Linux distros use that feature as part of the kernel update mechanism)
Sorry, I did not make that clear. If you click the go ahead to a kernel update, an image of the updated kernel is created in the background, while you are running the system using the old kernel. If you then do a normal reboot, the system will use the new kernel image. The old kernel image is not deleted. If you get problems with the new kernel image, you can still boot with the old kernel image.