[fedora-virt] Suspending VMs on host shutdown

[Dor Laor]

On 08/15/2011 05:38 AM, Eric Blake wrote:
> On 08/15/2011 04:12 AM, Tom Hughes wrote:
>> My specific example was that this morning qemu-kvm updated from
>> 0.15.0-1.fc15 to 0.15.0-0.3.201108040af4922.fc15 and shortly after that
>> I restarted my host only to find that the VM that had been running for
>> some time wouldn't start. Looking at the logs showed:
>>
>>      Unknown savevm section or instance 'kvmclock' 0
>>      load of migration failed
>
> That's not good, and it would be nice if we could improve the situation.
>    However,

The above is a bug, there is a mechanism to take care of preserving 
older version format by specifying a 'machine type' flag using -M 
qemu0.15. I do think it is there on default so it is just a but in this 
case.

In general, I doubt that savevm is a good thing on host shutdown anyway.
When the guests will be restored, they'll have a time gap and also their 
tcp connections will probably stop be relevant. It's better to trigger 
internal guest hibernation (which has some caveats now) or shutdown the 
guest as you've said).

>
>> There also doesn't seem to be any way to tell libvirt to ignore the
>> saved image and do a new boot.
>
> This already exists.  'virsh managedsave-remove dom' prior to 'virsh
> start' will nuke the saved image and let the start do a fresh boot.
>