[openstack-dev] [nova][object] One question to the resource tracker session

yunhong jiang yunhong.jiang at linux.intel.com
Tue Nov 19 00:17:04 UTC 2013

On Fri, 2013-11-15 at 22:42 +0000, Jiang, Yunhong wrote:
> I have no particular part thus any part that need help is ok for me.
> My own purpose is to support dynamic resource claim to support live migration to instance with hardware allocated. For instance with device assigned (PCI device, USB or everything), we can't migrate it unless it's unplugged.
> Also currently the resource tracker is more than tracker, it in fact also update host to the instance, which I assume should be done by conducto. It even create the migration object, which I  think should also be created by conductor. IIUC, the reason is to keep the atomic operation to avoid race with the audit. 
> Combine the above two, I'm considering if we can change current resource tracker. Instead of passing the instance/flavor, a new object, resource requirement is used.  The process is: the conductor calculate the resource requirement for the instance on both building and resize , and passing it to the resource tracker, the resource tracker will add the hypervisor overhead, and then claim it. If the claim is success, the resource tracker save this resource requirement to the database.
> For build time, this should work well. For resize, this should also work, only that the instance will have two resource requirement. And there will be no race condition here. Other than that, another benefit is, the resource tracker don't need care for the flavor anymore. I'm not sure if we can totally remove the new_/old_ flavor information in system_metadata, but we can move the key user of it.
> Your opinion?

Paul/Andrew, I created a documentation about my idea at
https://docs.google.com/document/d/1gI_GE0-H637lTRIyn2UPfQVebfk5QjDi6ohObt6MIc0 , can you have a look on it?


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