From d8f7638d02f7354cea7283bde626d05fb11ae3db Mon Sep 17 00:00:00 2001
From: Vladyslav Drok <vdrok@mirantis.com>
Date: Fri, 31 Aug 2018 16:04:22 +0300
Subject: [PATCH] Fix resource tracker updates during instance evacuation

Current _update_usage_from_migrations code takes into account
only REBUILDING task state, while not handling properly rebuilding
spawn and rebuilding volume attachments. This can cause issues with
numa topologies or pci devices if several instances are being
evacuated and some of them begin evacuation prior to
update_available_resource periodic pass and others immediately after,
causing latter ones to claim e.g. already pinned cpus.

Closes-Bug: 1791075
Change-Id: I22aa680b00ae839c4acbc06cbfbc56dd27d5ab73
---
 nova/compute/resource_tracker.py              |  5 ++---
 nova/compute/task_states.py                   |  7 +++++++
 .../unit/compute/test_resource_tracker.py     | 21 +++++++++++++++++++
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/nova/compute/resource_tracker.py b/nova/compute/resource_tracker.py
index de99246dc2..d326bdc0d6 100644
--- a/nova/compute/resource_tracker.py
+++ b/nova/compute/resource_tracker.py
@@ -65,9 +65,8 @@ def _instance_in_resize_state(instance):
         return True
 
     if (vm in [vm_states.ACTIVE, vm_states.STOPPED]
-            and task in [task_states.RESIZE_PREP,
-            task_states.RESIZE_MIGRATING, task_states.RESIZE_MIGRATED,
-            task_states.RESIZE_FINISH, task_states.REBUILDING]):
+            and task in (
+                task_states.resizing_states + task_states.rebuild_states)):
         return True
 
     return False
diff --git a/nova/compute/task_states.py b/nova/compute/task_states.py
index b247d8696f..d549eb70a7 100644
--- a/nova/compute/task_states.py
+++ b/nova/compute/task_states.py
@@ -123,3 +123,10 @@ ALLOW_REBOOT = [None, REBOOTING, REBOOT_PENDING, REBOOT_STARTED, RESUMING,
 # These states indicate a reboot
 soft_reboot_states = (REBOOTING, REBOOT_PENDING, REBOOT_STARTED)
 hard_reboot_states = (REBOOTING_HARD, REBOOT_PENDING_HARD, REBOOT_STARTED_HARD)
+
+# These states indicate a resize in progress
+resizing_states = (RESIZE_PREP, RESIZE_MIGRATING, RESIZE_MIGRATED,
+                   RESIZE_FINISH)
+
+# These states indicate a rebuild
+rebuild_states = (REBUILDING, REBUILD_BLOCK_DEVICE_MAPPING, REBUILD_SPAWNING)
diff --git a/nova/tests/unit/compute/test_resource_tracker.py b/nova/tests/unit/compute/test_resource_tracker.py
index 0ef183779e..b77fd77ba9 100644
--- a/nova/tests/unit/compute/test_resource_tracker.py
+++ b/nova/tests/unit/compute/test_resource_tracker.py
@@ -2758,6 +2758,27 @@ class TestUpdateUsageFromMigrations(BaseTestCase):
         self.assertFalse(upd_mock.called)
         self.assertEqual(mig1.status, "error")
 
+    @mock.patch('nova.objects.migration.Migration.save')
+    @mock.patch.object(resource_tracker.ResourceTracker,
+                       '_update_usage_from_migration')
+    def test_evacuate_and_resizing_states(self, mock_update_usage, mock_save):
+        self._setup_rt()
+        migration_context = objects.MigrationContext(migration_id=1)
+        instance = objects.Instance(
+            vm_state=vm_states.STOPPED, task_state=None,
+            migration_context=migration_context)
+        migration = objects.Migration(
+            source_compute='other-host', source_node='other-node',
+            dest_compute=_HOSTNAME, dest_node=_NODENAME,
+            instance_uuid=uuids.instance, id=1, instance=instance)
+        for state in task_states.rebuild_states + task_states.resizing_states:
+            instance.task_state = state
+            self.rt._update_usage_from_migrations(
+                mock.sentinel.ctx, [migration], _NODENAME)
+            mock_update_usage.assert_called_once_with(
+                mock.sentinel.ctx, instance, migration, _NODENAME)
+            mock_update_usage.reset_mock()
+
 
 class TestUpdateUsageFromInstance(BaseTestCase):