Maybe I misunderstand, but I thought: kexec - lets you boot a new kernel/initrd starting at the point a boot loader would skipping the bios init. All previous running processes are not running in the new boot just like a normal reboot.
CRIU - Lets you snapshot/restart running processes. While you could use both together to upgrades kernel while leaving all the processes running after the reboot, I don't think that's very tested at the moment. checkpointing the system memory is not without cost too. Restarting the services may be faster. I think we're pretty far off in a tangent though. My main point was, if you can't selectively restart services as needed, I'm not sure how useful patching the image really is over a full reboot. It should take on the same order of magnitude service unavailability I think. Thanks, Kevin ________________________________________ From: Clint Byrum [cl...@fewbar.com] Sent: Wednesday, January 22, 2014 12:36 PM To: openstack-dev Subject: Re: [openstack-dev] [TripleO] our update story: can people live with it? Excerpts from Fox, Kevin M's message of 2014-01-22 12:19:56 -0800: > I think most of the time taken to reboot is spent in bringing down/up the > services though, so I'm not sure what it really buys you if you do it all. It > may let you skip the crazy long bootup time on "enterprise" hardware, but > that could be worked around with kexec on the full reboot method too. > If we could get kexec reliable.. but I have no evidence that it is anything but a complete flake. What it saves you is losing running processes that you don't end up killing, which is expensive on many types of services.. Nova Compute being a notable example. _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
