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Comment by bjackman | Hacker News Reader

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bjackman·

This is cool as fuck, I didn't know about kpatch or kGraft.

Does anyone know if any other OSs have live kernel patching?

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FreeBSD has not gone quite that far, but there was a PoC for loading new kernels without rebooting.

https://www.bsdcan.org/2012/schedule/events/325.en.html

Yup Linux has had a similar feature, kexec, for several years.

Everyone I talked to about it since has said "nobody seems to care enough to bother completing it"

It is kind of a niche feature, really.

Linux has this create feature of being able to include the operating system in the initrd. Put this with a nice PXE infrastructure where you pxe the OS and download the initrd with the OS in it. Then you simply kexec to upgrade or downgrade the entire operating system in ~30 seconds. I used to manage a production environment that worked exactly this way for several thousand nodes.

Not sure I'd call it niche, but yes, somewhat specialized.

Not that it matters too much for the current ecosystem, but Lisp Machines had this 25 years+ ago.

Windows Server 2003 had a live patching feature [1] and it was also applicable to kernel patching according to [2]. For some reason it was quickly abandoned, though.

[1] https://technet.microsoft.com/en-us/library/cc781109%28v=ws....

[2] http://jpassing.com/2011/05/01/windows-hotpatching/

I was told by Andrew Tanenbaum some time ago that Minix has had this kind of feature for a number of years now.

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