Update resources once in update_available_resource

This change ensures that resources are updated only once per
update_available_resource() call.

Compute resources were previously updated during host
object initialization and at the end of
update_available_resource(). It could cause inconsistencies
in resource tracking between compute host and DB for couple
of second when final _update() at the end of
update_available_resource() is being called.

For example: nova-api shows that host uses 10GB of RAM, but
in fact its 12GB because DB doesn't have resources that belongs
to shutdown instance.

Because of that fact nova-scheduler (CachingScheduler) could
choose (based on imcomplete information) host which is already full.

For more informations please see realted bug: #1729621

Conflicts:
    nova/tests/unit/compute/test_resource_tracker.py

NOTE: The conflict is due to the backporting order of this patch and
I9fa1d509a3de405d6246fb8670612c65c10cc93b to pike has changed. This
caused the conflict in first place, and also modification needed in
test_compute_node_create_fail_retry_works(), which is now exactly the
same as it was originally implemented in queens by the patch mentioned
above.

Change-Id: I120a98cc4c11772f24099081ef3ac44a50daf71d
Closes-Bug: #1729621
(cherry picked from commit c9b74bcfa09d11c2046ce1bfb6dd8463b3a2f3b0)
(cherry picked from commit 36d93675d9a6bf903ed64c216243c74a639a2087)

2 files changed, 13 insertions, 13 deletions

diff --git a/nova/compute/resource_tracker.py b/nova/compute/resource_tracker.py
index 4ffafd3a34..adf26260c3 100644
--- a/nova/compute/resource_tracker.py
+++ b/nova/compute/resource_tracker.py
@@ -583,7 +583,6 @@ class ResourceTracker(object):
             cn = self.compute_nodes[nodename]
             self._copy_resources(cn, resources)
             self._setup_pci_tracker(context, cn, resources)
-            self._update(context, cn)
             return
 
         # now try to get the compute node record from the
@@ -593,7 +592,6 @@ class ResourceTracker(object):
             self.compute_nodes[nodename] = cn
             self._copy_resources(cn, resources)
             self._setup_pci_tracker(context, cn, resources)
-            self._update(context, cn)
             return
 
         if self._check_for_nodes_rebalance(context, resources, nodename):
@@ -616,7 +614,6 @@ class ResourceTracker(object):
                  {'host': self.host, 'node': nodename, 'uuid': cn.uuid})
 
         self._setup_pci_tracker(context, cn, resources)
-        self._update(context, cn)
 
     def _setup_pci_tracker(self, context, compute_node, resources):
         if not self.pci_tracker:
diff --git a/nova/tests/unit/compute/test_resource_tracker.py b/nova/tests/unit/compute/test_resource_tracker.py
index 4d440f17ca..9e9534b9cd 100644
--- a/nova/tests/unit/compute/test_resource_tracker.py
+++ b/nova/tests/unit/compute/test_resource_tracker.py
@@ -568,6 +568,7 @@ class TestUpdateAvailableResources(BaseTestCase):
         actual_resources = update_mock.call_args[0][1]
         self.assertTrue(obj_base.obj_equal_prims(expected_resources,
                                                  actual_resources))
+        update_mock.assert_called_once()
 
     @mock.patch('nova.objects.InstancePCIRequests.get_by_instance',
                 return_value=objects.InstancePCIRequests(requests=[]))
@@ -608,6 +609,7 @@ class TestUpdateAvailableResources(BaseTestCase):
         actual_resources = update_mock.call_args[0][1]
         self.assertTrue(obj_base.obj_equal_prims(expected_resources,
                                                  actual_resources))
+        update_mock.assert_called_once()
 
     @mock.patch('nova.objects.InstancePCIRequests.get_by_instance',
                 return_value=objects.InstancePCIRequests(requests=[]))
@@ -655,6 +657,7 @@ class TestUpdateAvailableResources(BaseTestCase):
         actual_resources = update_mock.call_args[0][1]
         self.assertTrue(obj_base.obj_equal_prims(expected_resources,
                                                  actual_resources))
+        update_mock.assert_called_once()
 
     @mock.patch('nova.objects.InstancePCIRequests.get_by_instance',
                 return_value=objects.InstancePCIRequests(requests=[]))
@@ -718,6 +721,7 @@ class TestUpdateAvailableResources(BaseTestCase):
         actual_resources = update_mock.call_args[0][1]
         self.assertTrue(obj_base.obj_equal_prims(expected_resources,
                                                  actual_resources))
+        update_mock.assert_called_once()
 
     @mock.patch('nova.objects.InstancePCIRequests.get_by_instance',
                 return_value=objects.InstancePCIRequests(requests=[]))
@@ -780,6 +784,7 @@ class TestUpdateAvailableResources(BaseTestCase):
         actual_resources = update_mock.call_args[0][1]
         self.assertTrue(obj_base.obj_equal_prims(expected_resources,
                                                  actual_resources))
+        update_mock.assert_called_once()
 
     @mock.patch('nova.objects.InstancePCIRequests.get_by_instance',
                 return_value=objects.InstancePCIRequests(requests=[]))
@@ -839,6 +844,7 @@ class TestUpdateAvailableResources(BaseTestCase):
         actual_resources = update_mock.call_args[0][1]
         self.assertTrue(obj_base.obj_equal_prims(expected_resources,
                                                  actual_resources))
+        update_mock.assert_called_once()
 
     @mock.patch('nova.objects.InstancePCIRequests.get_by_instance',
                 return_value=objects.InstancePCIRequests(requests=[]))
@@ -894,6 +900,7 @@ class TestUpdateAvailableResources(BaseTestCase):
         actual_resources = update_mock.call_args[0][1]
         self.assertTrue(obj_base.obj_equal_prims(expected_resources,
                                                  actual_resources))
+        update_mock.assert_called_once()
 
     @mock.patch('nova.objects.InstancePCIRequests.get_by_instance',
                 return_value=objects.InstancePCIRequests(requests=[]))
@@ -962,6 +969,7 @@ class TestUpdateAvailableResources(BaseTestCase):
         actual_resources = update_mock.call_args[0][1]
         self.assertTrue(obj_base.obj_equal_prims(expected_resources,
                                                  actual_resources))
+        update_mock.assert_called_once()
 
 
 class TestInitComputeNode(BaseTestCase):
@@ -987,7 +995,7 @@ class TestInitComputeNode(BaseTestCase):
         self.assertFalse(get_mock.called)
         self.assertFalse(create_mock.called)
         self.assertTrue(pci_mock.called)
-        self.assertTrue(update_mock.called)
+        self.assertFalse(update_mock.called)
 
     @mock.patch('nova.objects.PciDeviceList.get_by_compute_node',
                 return_value=objects.PciDeviceList())
@@ -1011,7 +1019,7 @@ class TestInitComputeNode(BaseTestCase):
         get_mock.assert_called_once_with(mock.sentinel.ctx, _HOSTNAME,
                                          _NODENAME)
         self.assertFalse(create_mock.called)
-        self.assertTrue(update_mock.called)
+        self.assertFalse(update_mock.called)
 
     @mock.patch('nova.objects.ComputeNodeList.get_by_hypervisor')
     @mock.patch('nova.objects.PciDeviceList.get_by_compute_node',
@@ -1165,7 +1173,7 @@ class TestInitComputeNode(BaseTestCase):
         create_mock.assert_called_once_with()
         self.assertTrue(obj_base.obj_equal_prims(expected_compute, cn))
         setup_pci.assert_called_once_with(mock.sentinel.ctx, cn, resources)
-        self.assertTrue(update_mock.called)
+        self.assertFalse(update_mock.called)
 
     @mock.patch('nova.compute.resource_tracker.ResourceTracker.'
                 '_setup_pci_tracker')
@@ -1195,11 +1203,8 @@ class TestInitComputeNode(BaseTestCase):
             _cn.uuid = uuids.cn_uuid
             return original_copy_resources(_cn, _resources)
 
-        with test.nested(
-            mock.patch.object(self.rt, '_copy_resources',
-                              fake_copy_resources),
-            mock.patch.object(self.rt, '_update')
-        ) as (mock_copy_resources, mock_update):
+        with mock.patch.object(self.rt, '_copy_resources',
+                               fake_copy_resources):
             self.rt._init_compute_node(ctxt, resources)
         self.assertIn(_NODENAME, self.rt.compute_nodes)
         mock_get.assert_has_calls([mock.call(
@@ -1207,8 +1212,6 @@ class TestInitComputeNode(BaseTestCase):
         self.assertEqual(2, mock_create.call_count)
         mock_setup_pci.assert_called_once_with(
             ctxt, test.MatchType(objects.ComputeNode), resources)
-        mock_update.assert_called_once_with(
-            ctxt, self.rt.compute_nodes[_NODENAME])
 
     @mock.patch('nova.objects.ComputeNodeList.get_by_hypervisor')
     @mock.patch('nova.objects.ComputeNode.create')