Merge "Cleanup comments around claim_resources method"

nova/conductor/manager.py

@@ -922,7 +922,7 @@ class ComputeTaskManager(base.Base):
                                 'not found.', instance.host, instance.node,
                                 instance=instance)
 
-        # TODO(mriedem): In Queens, call select_destinations() with a
+        # TODO(mriedem): Call select_destinations() with a
         # skip_filters=True flag so the scheduler does the work of
         # claiming resources on the destination in Placement but still
         # bypass the scheduler filters, which honors the 'force' flag

nova/conductor/tasks/live_migrate.py

@@ -97,7 +97,7 @@ class LiveMigrationTask(base.TaskBase):
             # to the destination compute node. Normally select_destinations()
             # in the scheduler would do this for us, but when forcing the
             # target host we don't call the scheduler.
-            # TODO(mriedem): In Queens, call select_destinations() with a
+            # TODO(mriedem): Call select_destinations() with a
             # skip_filters=True flag so the scheduler does the work of claiming
             # resources on the destination in Placement but still bypass the
             # scheduler filters, which honors the 'force' flag in the API.

nova/scheduler/client/report.py

@@ -1524,13 +1524,16 @@ class SchedulerReportClient(object):
         return allocations.get(
             rp_uuid, {}).get('resources', {})
 
-    # NOTE(jaypipes): Currently, this method is ONLY used in two places:
+    # NOTE(jaypipes): Currently, this method is ONLY used in three places:
     # 1. By the scheduler to allocate resources on the selected destination
     #    hosts.
     # 2. By the conductor LiveMigrationTask to allocate resources on a forced
-    #    destination host. This is a short-term fix for Pike which should be
-    #    replaced in Queens by conductor calling the scheduler in the force
-    #    host case.
+    #    destination host. In this case, the source node allocations have
+    #    already been moved to the migration record so the instance should not
+    #    have allocations and _move_operation_alloc_request will not be called.
+    # 3. By the conductor ComputeTaskManager to allocate resources on a forced
+    #    destination host during evacuate. This case will call the
+    #    _move_operation_alloc_request method.
     # This method should not be called by the resource tracker.
     @safe_connect
     @retries
@@ -1546,10 +1549,7 @@ class SchedulerReportClient(object):
         host). In order to prevent compute nodes currently performing move
         operations from being scheduled to improperly, we create a "doubled-up"
         allocation that consumes resources on *both* the source and the
-        destination host during the move operation. When the move operation
-        completes, the destination host will end up setting allocations for the
-        instance only on the destination host thereby freeing up resources on
-        the source host appropriately.
+        destination host during the move operation.
 
         :param context: The security context
         :param consumer_uuid: The instance's UUID.

nova/scheduler/utils.py

@@ -596,9 +596,7 @@ def claim_resources_on_destination(
             # the host. This is because we need Placement to have an
             # accurate reflection of what's allocated on all nodes so the
             # scheduler can make accurate decisions about which nodes have
-            # capacity for building an instance. We also cannot rely on the
-            # resource tracker in the compute service automatically healing
-            # the allocations since that code is going away in Queens.
+            # capacity for building an instance.
             reason = (_('Unable to move instance %(instance_uuid)s to '
                         'host %(host)s. There is not enough capacity on '
                         'the host for the instance.') %