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To be clear - the changes that Yunhong describes below are not part of the extensible-resource-tracking blueprint. Extensible-resource-tracking has the more modest aim to provide plugins to track additional resource data.
	
Paul.

-----Original Message-----
From: Jiang, Yunhong [mailto:yunhong.jiang at intel.com] 
Sent: 17 January 2014 05:54
To: OpenStack Development Mailing List (not for usage questions)
Subject: Re: [openstack-dev] [nova] how is resource tracking supposed to work for live migration and evacuation?

There are some related discussion on this before. 

There is a BP at https://blueprints.launchpad.net/nova/+spec/extensible-resource-tracking which try to support more resources.

And I have a documentation at  https://docs.google.com/document/d/1gI_GE0-H637lTRIyn2UPfQVebfk5QjDi6ohObt6MIc0 . My idea is to keep the claim as an object which can be invoked remotely, and the claim result is kept in DB as the instance's usage. I'm working on it now.

Thanks
--jyh

> -----Original Message-----
> From: Vishvananda Ishaya [mailto:vishvananda at gmail.com]
> Sent: Thursday, January 16, 2014 2:27 PM
> To: OpenStack Development Mailing List (not for usage questions)
> Subject: Re: [openstack-dev] [nova] how is resource tracking supposed 
> to work for live migration and evacuation?
> 
> 
> On Jan 16, 2014, at 1:12 PM, Chris Friesen 
> <chris.friesen at windriver.com>
> wrote:
> 
> > Hi,
> >
> > I'm trying to figure out how resource tracking is intended to work 
> > for live
> migration and evacuation.
> >
> > For a while I thought that maybe we were relying on the call to
> ComputeManager._instance_update() in
> ComputeManager.post_live_migration_at_destination().  However, in
> > ResourceTracker.update_usage() we see that on a live migration the
> instance that has just migrated over isn't listed in 
> self.tracked_instances and so we don't actually update its usage.
> >
> > As far as I can see, the current code will just wait for the audit 
> > to run at
> some unknown time in the future and call update_available_resource(), 
> which will add the newly-migrated instance to self.tracked_instances 
> and update the resource usage.
> >
> > From my poking around so far the same thing holds true for 
> > evacuation
> as well.
> >
> > In either case, just waiting for the audit seems somewhat haphazard.
> >
> > Would it make sense to do something like
> ResourceTracker.instance_claim() during the migration/evacuate and 
> properly track the resources rather than wait for the audit?
> 
> Yes that makes sense to me. Live migration was around before we had a 
> resource tracker so it probably was just never updated.
> 
> Vish
> 
> >
> > Chris
> >
> > _______________________________________________
> > OpenStack-dev mailing list
> > OpenStack-dev at lists.openstack.org
> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev


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