According to our resident Xen expert, any PV kernel automatically syncs to the hardware clock on dom0.
On 5/15/13 9:50 AM, "John Burwell" <jburw...@basho.com> wrote: >Marcus, > >Agreed. I think we need to add a set of hypervisor agnostic time >keeping guidelines to the documentation. I just wanted to make sure >there wasn't anything KVM specific that should be added as well. > >Thanks, >-John > >On May 15, 2013, at 12:48 PM, Marcus Sorensen <shadow...@gmail.com> wrote: > >> Just the general one that system vms sync their time to the >> hypervisor, thus admins need to keep the hypervisor time correct. It >> sounds like that will be the case for all three, if we can manage it. >> >> On Wed, May 15, 2013 at 10:44 AM, John Burwell <jburw...@basho.com> >>wrote: >>> Marcus, >>> >>> Excellent. So, it looks like we have KVM resolved. We just need to >>>address Xen and VMWare now. Do you think we need to any guidance to >>>the documentation regarding KVM time keeping (e.g. environmental >>>prerequisites)? >>> >>> Thanks, >>> -John >>> >>> >>> >>> On May 15, 2013, at 12:39 PM, Marcus Sorensen <shadow...@gmail.com> >>>wrote: >>> >>>> KVM LibvirtComputingResource has been patched in master. Tested on >>>> master, 4.1, and both the acton and current system vm templates. This >>>> patch makes system vms use 'kvmclock' for their timer, which is a vm >>>> driver that gets it's time from the hypervisor. No change to the >>>> system vm template itself. >>>> >>>> bfc5887a1bf6b41e88dd7a8f9987fcee8d3d9175 >>>> >>>> On Wed, May 15, 2013 at 9:08 AM, Chip Childers >>>> <chip.child...@sungard.com> wrote: >>>>> On Wed, May 15, 2013 at 11:03:16AM -0400, John Burwell wrote: >>>>>> Chip, >>>>>> >>>>>> One other item I neglected to mention was that clock sync, at least >>>>>>for Xen system VMs, wasn't an issue in the Jan-Feb timeframe. >>>>>>Previously when I encountered these issues, syncing the host's clock >>>>>>and rebuilding the system VMs addressed the issue. I assumed, but >>>>>>never verified, that the SSVM was syncing back against the host's >>>>>>clock through hypervisor. During my testing yesterday, aside from >>>>>>hard setting the clock, I was unable to force clock sync on the SSVM. >>>>>> >>>>>> Thanks, >>>>>> -John >>>>> >>>>> I think that's our issue right now... answering the question: Why is >>>>> this only an issue now? Did we just get lucky up to this point? >>>>>Since >>>>> the SSVMs are the same template as the timeframe you mention, I tend >>>>>to >>>>> believe that you / we were just lucky. >>>>> >>>>> Anyone else have thoughts? >>>>> >>>>>> >>>>>> On May 15, 2013, at 10:18 AM, Chip Childers >>>>>><chip.child...@sungard.com> wrote: >>>>>> >>>>>>> Starting a thread on this specific issue. >>>>>>> >>>>>>> CLOUDSTACK-2492 was opened, which is basically the fact that the >>>>>>>System >>>>>>> VMs aren't syncing time to the host or to an NTP server. The S3 >>>>>>> integration is broken because of this problem, and therefore could >>>>>>>not >>>>>>> be considered a function available in 4.1 if we release as is. >>>>>>> >>>>>>> We need input from people that know about the current system VMs >>>>>>>(the >>>>>>> 3.x VMs), as well as the possibility of using the newer ones that >>>>>>>we >>>>>>> have been considering experimental for 4.1.0. >>>>>>> >>>>>>> What should we do? >>>>>>> >>>>>>> -chip >>>>>> >>>>>> >>> >
