libvirt users - Sep 2014 - Re: time setting after suspend/resume

Hi,
	I am using libvirt with qemu/kvm with qemu-guest-agent and
suspend/save/resume linux and windows vm's.  Time in Windows gets
handled fine with ntp but I can get neither ntp or chrony to sync after
resume without manually setting the time close to correct first.

Searching has gotten me to the point where I can manually set the time
using qemu-guest-agent but I cant figure out how to get libvirt to
automaticly trigger this on resume.  I am finding information saying it
works but not how, or that its still work in progress and not
implemented yet (but patches exist).  Can someone either say "its not
working yet" or explain what I am missing please?

BillK

On Fri, Sep 26, 2014 at 08:16:25AM +0800, Bill Kenworthy
wrote:
>Hi,
>	I am using libvirt with qemu/kvm with qemu-guest-agent and
>suspend/save/resume linux and windows vm's.  Time in Windows gets
>handled fine with ntp but I can get neither ntp or chrony to sync after
>resume without manually setting the time close to correct first.
>
>Searching has gotten me to the point where I can manually set the time
>using qemu-guest-agent but I cant figure out how to get libvirt to
>automaticly trigger this on resume.  I am finding information saying it
>works but not how, or that its still work in progress and not
>implemented yet (but patches exist).  Can someone either say "its not
>working yet" or explain what I am missing please?
>
What version of libvirt are you using?  Since 1.2.5 there's
virDomainSetTime() API that can do this and since 1.2.8 it's called
automatically after resume.

Martin

On 29/09/14 16:28, Martin Kletzander wrote:
> On Fri, Sep 26, 2014 at 08:16:25AM +0800, Bill Kenworthy wrote:
>> Hi,
>>     I am using libvirt with qemu/kvm with qemu-guest-agent and
>> suspend/save/resume linux and windows vm's.  Time in Windows gets
>> handled fine with ntp but I can get neither ntp or chrony to sync after
>> resume without manually setting the time close to correct first.
>>
>> Searching has gotten me to the point where I can manually set the time
>> using qemu-guest-agent but I cant figure out how to get libvirt to
>> automaticly trigger this on resume.  I am finding information saying it
>> works but not how, or that its still work in progress and not
>> implemented yet (but patches exist).  Can someone either say "its
not
>> working yet" or explain what I am missing please?
>>
> 
> What version of libvirt are you using?  Since 1.2.5 there's
> virDomainSetTime() API that can do this and since 1.2.8 it's called
> automatically after resume.
> 
> Martin
Thanks Martin for replying.

I am using 1.2.6.  I presume that there is no way to get 1.2.6 to
trigger it after resume (has to be manual) so I'll have to upgrade to 1.2.8.

Thanks,
BillK

On 09/29/2014 02:28 AM, Martin Kletzander wrote:
> On Fri, Sep 26, 2014 at 08:16:25AM +0800, Bill Kenworthy wrote:
>> Hi,
>>     I am using libvirt with qemu/kvm with qemu-guest-agent and
>> suspend/save/resume linux and windows vm's.  Time in Windows gets
>> handled fine with ntp but I can get neither ntp or chrony to sync after
>> resume without manually setting the time close to correct first.
>>
>> Searching has gotten me to the point where I can manually set the time
>> using qemu-guest-agent but I cant figure out how to get libvirt to
>> automaticly trigger this on resume.  I am finding information saying it
>> works but not how, or that its still work in progress and not
>> implemented yet (but patches exist).  Can someone either say "its
not
>> working yet" or explain what I am missing please?
>>
> 
> What version of libvirt are you using?  Since 1.2.5 there's
> virDomainSetTime() API that can do this and since 1.2.8 it's called
> automatically after resume.
Umm, I have a problem with that statement.  Anything that requires guest
interaction (which guest-agent set-time does) must NOT default to being
automatic; it is only safe to enable if explicitly allowed.  What is the
domain XML that must be explicitly set in order to turn on automatic
time-set after resume?

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org