Linux Kernel Developers Consider Live Kernel Patching Solution

Updating the Linux kernel without restarting, also known as live kernel patching, is a luxury available so far only to a select few server administrators. But that could change as a result of kGraft and kPatch, which may make reboot-less kernel updates a standard part of the open source operating system.

kGraft and kPatch currently make live kernel patching available in openSUSE, as well as the most recent iteration of its commercial cousin, SUSE Linux Enterprise Server, which launched in October. And as seasoned Linux server administrators probably know,the SUSE-related distributions are not the only ones that can pull off this trick. Other software, including KernelCare and Ksplice, has been around for a while that also does live kernel patching on other Linux flavors. Ksplice supports reboot-less updates on Oracle Linux 7, for example.

But kGraft and kPatch may become notable because Linux kernel developers are now discussing the possibility of integrating them into the core Linux kernel code. That would bring live kernel patching to all Linux distributions, making it possible to apply all updates—even those that bump the lowest-level kernel code up to a new version—without having to reboot.

That may not turn the heads of many open source fans. If you’re running Linux on your PC or mobile device, having to reboot once every few weeks to apply a major kernel update is probably not your biggest problem in life. (If it is, there are plenty of people who’d be happy to exchange their problems for yours.)

But on servers, uptime is just as important as security, reliability and efficiency. Having to reboot to apply kernel patches, including those that fix security issues, is the main reason that 100 percent uptime is not theoretically possible on most Linux servers. But if kPatch and kGraph make it into the mainline kernel code, all Linux servers will be able to boast stand-out uptimes, giving the open source operating system another leg up against proprietary competitors.