Open Stack

When we create a new instance via _build_instance() or 
_build_and_run_instance(), in both cases we call instance_claim() to 
reserve and test for resources.

During a cold migration I see us calling prep_resize() which calls 
resize_claim().

How come we don't need to do something like this when we live migrate an 
instance?  Do we track the hypervisor overhead somewhere in the instance?

Chris