On Sat, 2020-09-26 at 11:45 -0400, Sam Varshavchik wrote:
Patrick O'Callaghan writes:
There is a long-standing project that aims to do something like that ( https://github.com/dynup/kpatch), but AFAIK it's not production quality so far. Personally, I'm sceptical that it will ever be useful except in very constrained conditions. For one thing, it's not clear that there's much demand for it.
No, that's not what this is trying to do. Not even close.
This project attempts to implement the ability to patch the running kernel, in a number of limited situations.
This is nowhere close to loading a brand new kernel and somehow seamlessly switching to it.
For completeness, I'll mention that there are solutions that semantically reboot into a brand new kernel but transfer the userspace state to it with a minimum of actual downtime:
https://criu.org/Seamless_kernel_upgrade
This is like hibernating and immediately resuming except that the userspace state is transferred in a format that is compatible across kernel versions. However, it's unclear if any of these solutions are reasonable for typical end users.
Matt