refactoring compute.api.create()

3 files changed, 17 insertions, 0 deletions

diff --git a/nova/scheduler/driver.py b/nova/scheduler/driver.py
index 2094e3565..237e31c04 100644
--- a/nova/scheduler/driver.py
+++ b/nova/scheduler/driver.py
@@ -72,6 +72,13 @@ class Scheduler(object):
                 for service in services
                 if self.service_is_up(service)]
 
+    def should_create_all_at_once(self, context=None, *args, **kwargs):
+        """
+        Does this driver prefer single-shot requests or all-at-once?
+        By default, prefer single-shot.
+        """
+        return False
+
     def schedule(self, context, topic, *_args, **_kwargs):
         """Must override at least this method for scheduler to work."""
         raise NotImplementedError(_("Must implement a fallback schedule"))
diff --git a/nova/scheduler/manager.py b/nova/scheduler/manager.py
index a6fc53be5..a29703aaf 100644
--- a/nova/scheduler/manager.py
+++ b/nova/scheduler/manager.py
@@ -74,6 +74,10 @@ class SchedulerManager(manager.Manager):
         """Select a list of hosts best matching the provided specs."""
         return self.driver.select(context, *args, **kwargs)
 
+    def get_scheduler_rules(self, context=None, *args, **kwargs):
+        """Ask the driver how requests should be made of it."""
+        return self.driver.get_scheduler_rules(context, *args, **kwargs)
+
     def _schedule(self, method, context, topic, *args, **kwargs):
         """Tries to call schedule_* method on the driver to retrieve host.
 
diff --git a/nova/scheduler/zone_aware_scheduler.py b/nova/scheduler/zone_aware_scheduler.py
index 58a9eca55..35ffdbde1 100644
--- a/nova/scheduler/zone_aware_scheduler.py
+++ b/nova/scheduler/zone_aware_scheduler.py
@@ -157,6 +157,12 @@ class ZoneAwareScheduler(driver.Scheduler):
         self._provision_resource_from_blob(context, item, instance_id,
                                                request_spec, kwargs)
 
+    def should_create_all_at_once(self, context=None, *args, **kwargs):
+        """
+        This driver prefers all-at-once requests.
+        """
+        return True
+
     def schedule_run_instance(self, context, instance_id, request_spec,
                                         *args, **kwargs):
         """This method is called from nova.compute.api to provision