Ksplice: kernel patches without reboots [LWN.net]

Ksplice: kernel patches without reboots

Posted Apr 30, 2008 3:11 UTC (Wed) by joey (subscriber, #328)
Parent article: Ksplice: kernel patches without reboots

One use case I can see is large xen hosting providers. Upgrading the domU kernels is a real
pain for such providers, because just rebooting all the user's machines won't work; a certian
number will fail to come up, users will hate you. Instead, a good hosting provider will let
the user choose when to reboot into a fixed kernel. But then some percentage of users never
will, and instead get cracked.

So I can see hotpatching the kernel being really appealing in that situation, even if it's
annoying to manage.

(Personally, I'd rather my xen hosting provider just let me build and run my *own* kernel. But
that's just me.)

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Foolish, not good

Posted Apr 30, 2008 4:33 UTC (Wed) by khim (subscriber, #9252) [Link]

Instead, a good hosting provider will let the user choose when to reboot into a fixed kernel.

Why? Xen long had a way to solve this problem: live migration. When and how user updates kernel in VPS installation is another question...

Foolish, not good

Posted Apr 30, 2008 6:51 UTC (Wed) by joey (subscriber, #328) [Link]

Live migration to a different version of the kernel?

I thought that xen's migration was of a whole domU, including kernel.

Foolish, not good

Posted May 1, 2008 13:20 UTC (Thu) by BenHutchings (subscriber, #37955) [Link]

You are correct. khim is probably thinking of what you do when dom0's kernel needs to be
patched.