[libvirt] [PATCH V4] implement offline migration

[Kamezawa Hiroyuki]

(2012/09/06 14:32), liguang wrote:
> Hello, Eric & Daniel
>
> 在 2012-09-05三的 11:08 -0600，Eric Blake写道：
>> On 09/05/2012 02:48 AM, Daniel P. Berrange wrote:
>>>>>
>>>>> I really don't like the general design of this patch, even
>>>>> ignoring all the code bugs. I think this entire patch is
>>>>> really just a solution in search of a problem. Offline migration
>>>>> is already possible with existing libvirt APIs:
>>
>> I agree that the existing patches are making too many assumptions and
>> not honoring flags correctly; but I'm still not sure why the user must
>> decompose offline migration into a sequence of calls...
>
> yes, my original thought was to do all things together.
>
>>
>>>>>
>>>>>     domsrc = virDomainLookupByName(connsrc, "someguest");
>>>>>     xml = virDomainGetXMLDesc(domsrc);
>>>>>     domdst virDomainDefine(conndst, xml);
>>>>>
>>>>
>>>> Um, maybe you mean offline migration is just redefinition of domain at
>>>> target side, but what about disk images the domain used without sharing
>>>> files between source and target, do we have to take a look at this case?
>>>
>>> Which can also be done already
>>>
>>>     virStorageVolDownload + virStorageVolUpload
>>
>> ...when a single virMigrate API could do the same decomposition as
>> syntactic sugar, if the patch were cleaned up to actually obey flags.
>> That is, why must virMigrate be a live-only operation, forcing
>> virt-manager and all other wrappers to re-implement the same giant
>> sequence of API calls for offline migration?
>>
>
> so, libvirt may prefer APIs do one thing only?
> maybe I have to just migrate the definition.
>

Can you try to move the definition in an atomic way ?
copy to the dest + delete the original with preventing other ops to the
target vm. I hope virsh migrate can support this "move" of definition....

Thanks,
-Kame