Teach resource tracker about stashed instance types

This removes instance_type-related database queries from the
resource_tracker.

Related to blueprint no-db-compute

Change-Id: Ia5dd407181fa733cc81d3ce03edc1c06c2aae762

2 files changed, 38 insertions, 23 deletions

diff --git a/nova/compute/resource_tracker.py b/nova/compute/resource_tracker.py
index f5d3a8008..825422e86 100644
--- a/nova/compute/resource_tracker.py
+++ b/nova/compute/resource_tracker.py
@@ -144,7 +144,8 @@ class ResourceTracker(object):
 
             # Mark the resources in-use for the resize landing on this
             # compute host:
-            self._update_usage_from_migration(self.compute_node, migration_ref)
+            self._update_usage_from_migration(instance_ref, self.compute_node,
+                                              migration_ref)
             elevated = context.elevated()
             self._update(elevated, self.compute_node)
 
@@ -158,12 +159,7 @@ class ResourceTracker(object):
         be done while the COMPUTE_RESOURCES_SEMAPHORE is held so the resource
         claim will not be lost if the audit process starts.
         """
-        # TODO(russellb): no-db-compute: Send the old instance type
-        # info that is needed via rpc so db access isn't required
-        # here.
-        old_instance_type_id = instance['instance_type_id']
-        old_instance_type = instance_types.get_instance_type(
-                old_instance_type_id)
+        old_instance_type = instance_types.extract_instance_type(instance)
 
         return self.conductor_api.migration_create(context, instance,
                 {'dest_compute': self.host,
@@ -379,7 +375,7 @@ class ResourceTracker(object):
         resources['running_vms'] = self.stats.num_instances
         resources['vcpus_used'] = self.stats.num_vcpus_used
 
-    def _update_usage_from_migration(self, resources, migration):
+    def _update_usage_from_migration(self, instance, resources, migration):
         """Update usage for a single migration.  The record may
         represent an incoming or outbound migration.
         """
@@ -392,7 +388,7 @@ class ResourceTracker(object):
                     migration['source_node'] == self.nodename)
         same_node = (incoming and outbound)
 
-        instance = self.tracked_instances.get(uuid, None)
+        record = self.tracked_instances.get(uuid, None)
         itype = None
 
         if same_node:
@@ -400,27 +396,25 @@ class ResourceTracker(object):
             # instance is *not* in:
             if (instance['instance_type_id'] ==
                 migration['old_instance_type_id']):
-
-                itype = migration['new_instance_type_id']
+                itype = instance_types.extract_instance_type(instance)
             else:
                 # instance record already has new flavor, hold space for a
                 # possible revert to the old instance type:
-                itype = migration['old_instance_type_id']
+                itype = instance_types.extract_instance_type(instance, 'old_')
 
-        elif incoming and not instance:
+        elif incoming and not record:
             # instance has not yet migrated here:
-            itype = migration['new_instance_type_id']
+            itype = instance_types.extract_instance_type(instance, 'new_')
 
-        elif outbound and not instance:
+        elif outbound and not record:
             # instance migrated, but record usage for a possible revert:
-            itype = migration['old_instance_type_id']
+            itype = instance_types.extract_instance_type(instance, 'old_')
 
         if itype:
-            instance_type = instance_types.get_instance_type(itype)
-            self.stats.update_stats_for_migration(instance_type)
-            self._update_usage(resources, instance_type)
+            self.stats.update_stats_for_migration(itype)
+            self._update_usage(resources, itype)
             resources['stats'] = self.stats
-            self.tracked_migrations[uuid] = (migration, instance_type)
+            self.tracked_migrations[uuid] = (migration, itype)
 
     def _update_usage_from_migrations(self, resources, migrations):
 
@@ -453,7 +447,8 @@ class ResourceTracker(object):
 
         for migration in filtered.values():
             try:
-                self._update_usage_from_migration(resources, migration)
+                self._update_usage_from_migration(instance, resources,
+                                                  migration)
             except exception.InstanceTypeNotFound:
                 LOG.warn(_("InstanceType could not be found, skipping "
                            "migration."), instance_uuid=uuid)
diff --git a/nova/tests/compute/test_resource_tracker.py b/nova/tests/compute/test_resource_tracker.py
index eaa0df5bf..f1d0d1f0c 100644
--- a/nova/tests/compute/test_resource_tracker.py
+++ b/nova/tests/compute/test_resource_tracker.py
@@ -19,6 +19,7 @@
 
 import uuid
 
+from nova.compute import instance_types
 from nova.compute import resource_tracker
 from nova.compute import task_states
 from nova.compute import vm_states
@@ -152,8 +153,22 @@ class BaseTestCase(test.TestCase):
         }
         return service
 
+    def _fake_instance_system_metadata(self, instance_type, prefix=''):
+        sys_meta = []
+        for key in instance_types.system_metadata_instance_type_props.keys():
+            sys_meta.append({'key': '%sinstance_type_%s' % (prefix, key),
+                             'value': instance_type[key]})
+        return sys_meta
+
     def _fake_instance(self, *args, **kwargs):
 
+        # Default to an instance ready to resize to or from the same
+        # instance_type
+        itype = self._fake_instance_type_create()
+        sys_meta = (self._fake_instance_system_metadata(itype) +
+                    self._fake_instance_system_metadata(itype, 'new_') +
+                    self._fake_instance_system_metadata(itype, 'old_'))
+
         instance_uuid = str(uuid.uuid1())
         instance = {
             'uuid': instance_uuid,
@@ -169,6 +184,7 @@ class BaseTestCase(test.TestCase):
             'node': None,
             'instance_type_id': 1,
             'launched_on': None,
+            'system_metadata': sys_meta,
         }
         instance.update(kwargs)
 
@@ -183,6 +199,9 @@ class BaseTestCase(test.TestCase):
             'vcpus': FAKE_VIRT_VCPUS,
             'root_gb': FAKE_VIRT_LOCAL_GB / 2,
             'ephemeral_gb': FAKE_VIRT_LOCAL_GB / 2,
+            'swap': 0,
+            'rxtx_factor': 1.0,
+            'vcpu_weight': 1,
             'flavorid': 'fakeflavor'
         }
         instance_type.update(**kwargs)
@@ -714,11 +733,12 @@ class ResizeClaimTestCase(BaseTrackerTestCase):
         # make an instance of src_type:
         instance = self._fake_instance(memory_mb=1, root_gb=1, ephemeral_gb=0,
                 vcpus=1, instance_type_id=2)
-
+        instance['system_metadata'] = self._fake_instance_system_metadata(
+            dest_type)
         self.tracker.instance_claim(self.context, instance, self.limits)
 
         # resize to dest_type:
-        claim = self.tracker.resize_claim(self.context, self.instance,
+        claim = self.tracker.resize_claim(self.context, instance,
                 dest_type, self.limits)
 
         self._assert(3, 'memory_mb_used')