This patch replaces the scheduler's use of GET
/resource_providers?resources=XXX with GET
/allocation_candidates?resources=XXX.
In doing so, we move the interaction with the placement API out of the
scheduler driver interface and up into the scheduler manager. This
allows us to make fewer changes to the underlying HostManager and
SchedulerDriver interfaces and isolate communication with the placement
API in a single place.
The provider_summaries part of the response from GET
/allocation_candidates is used to generate the UUIDs that winnow the
number of compute nodes retrieved by the filter scheduler during
scheduling. Following patches will add in support for actually doing
the claim from the scheduler against one or more resources providers by
examining the allocation_requests part of the HTTP response and picking
one that contains the host the scheduler picked during its _schedule()
loop.
Change-Id: I1c0bd2987dcbc38f23b71db2bc8e3267f85168c8
blueprint: placement-allocation-requests