Don't pass the entire list of instances to compute

We don't need to pass the entire (potentially large) list of instances
down to the compute node. This will save potentially thousands of
bytes in the message.

Fixes bug 1103669

Change-Id: Ia90a19dffa90575a0f02191603ae9e96ca9258df

nova/scheduler/filter_scheduler.py

@@ -47,15 +47,15 @@ class FilterScheduler(driver.Scheduler):
 
         Returns a list of the instances created.
         """
-        instance_uuids = request_spec.get('instance_uuids')
-        num_instances = len(instance_uuids)
-        LOG.debug(_("Attempting to build %(num_instances)d instance(s)") %
-                locals())
-
         payload = dict(request_spec=request_spec)
         notifier.notify(context, notifier.publisher_id("scheduler"),
                         'scheduler.run_instance.start', notifier.INFO, payload)
 
+        instance_uuids = request_spec.pop('instance_uuids')
+        num_instances = len(instance_uuids)
+        LOG.debug(_("Attempting to build %(num_instances)d instance(s)") %
+                locals())
+
         weighed_hosts = self._schedule(context, request_spec,
                 filter_properties, instance_uuids)
 
@@ -124,6 +124,8 @@ class FilterScheduler(driver.Scheduler):
             filter_properties, requested_networks, injected_files,
             admin_password, is_first_time, instance_uuid=None):
         """Create the requested resource in this Zone."""
+        # NOTE(vish): add our current instance back into the request spec
+        request_spec['instance_uuids'] = [instance_uuid]
         payload = dict(request_spec=request_spec,
                        weighted_host=weighed_host.to_dict(),
                        instance_id=instance_uuid)