[CentOS-virt] Timezone issues with migrations between host kernel 3.10 and 3.18

Thu Jul 30 17:06:23 UTC 2015
Nathan March <nathan at gt.net>

> -----Original Message-----
> From: centos-virt-bounces at centos.org [mailto:centos-virt-
> bounces at centos.org] On Behalf Of Johnny Hughes
> Sent: Thursday, July 30, 2015 4:41 AM
> To: centos-virt at centos.org
> Subject: Re: [CentOS-virt] Timezone issues with migrations between host
> kernel 3.10 and 3.18
> 
> On 07/30/2015 06:38 AM, Johnny Hughes wrote:
> > On 07/29/2015 11:38 AM, Nathan March wrote:
> >> Hi All,
> >>
> >>
> >>
> >> I'm seeing clock issues with live migrations on the latest kernel
> >> packages, migrating a VM from 3.10.68-11 to 3.18.17-13 results in the
> >> VM clock being off by 7 hours (I'm PST, so appears to be a timezone
> issue).
> >> This is also between xen versions, but rolling the target back to
> >> 3.10 resolved so don't believe the recent XSA's are related.
> >>
> >>
> >>
> >> Anyone else seen behavior like this or have any ideas on how to resolve?
> >
> > Some versions of CentOS have a hardware clock uses UTC check box.  If
> > that is on, and if your hardware clock is instead set to local time,
> > that can cause issues.
> >
> > Can you check that there is no UTC=True in /etc/sysconfig/clock
> 
> also, you can use tzselect to make sure the correct timezone is used.
> 

I considered that so I did use hwclock to confirm that the hardware clock / system clock were both the same between the two servers, and comparing /etc/adjtime between the two indicates the hwclock should have been local time on both sides (unless this got changed when I downgraded the kernel to resolve the issue).

Unfortunately I don't have a test machine for this at the moment, but can follow up in a couple weeks.

- Nathan