[openstack-dev] [Nova] Migration state machine proposal.

Jay Pipes jaypipes at gmail.com
Tue Oct 27 23:17:20 UTC 2015

On 10/27/2015 05:27 PM, Tang Chen wrote:
> On 10/27/2015 08:02 AM, Jay Pipes wrote:
>> Evacuate does *not* migrate/move anything. Evacuate *rebuilds* VMs
>> from their original source image.
> Well, I just dug into the source code. I think there could be some
> difference between evacuate in nova server side and client side. In nova
> compute, the evacuate API does call rebuild process as you said. But in
> novaclient, there is a command "nova host-evacuate-live", which will
> live-migrate all running VMs, which made me believe that evacuate also
> migrates VMs. Please refer to:
> https://github.com/openstack/python-novaclient/blob/master/novaclient/v2/contrib/host_evacuate_live.py#L72
> I think this is also a reason why I always got confused in all these
> concepts: cold-migrate, evacuate, evacuate-live, rebuild, resize.

Yes, this is a most unfortunate issue :( host-evacuate in the 
python-novaclient is not related at all to the evacuate server API.

We need to clean up this mess.


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