Merge "[OVN] Handle OVN agents when "Chassis" register is deleted" into stable/victoria

neutron/plugins/ml2/drivers/ovn/agent/neutron_agent.py

@@ -20,6 +20,12 @@ from neutron.common.ovn import constants as ovn_const
 from neutron.common.ovn import utils as ovn_utils
 
 
+class DeletedChassis(object):
+    external_ids = {}
+    hostname = '("Chassis" register deleted)'
+    name = '("Chassis" register deleted)'
+
+
 class NeutronAgent(abc.ABC):
     types = {}
 
@@ -35,9 +41,12 @@ class NeutronAgent(abc.ABC):
     def get_chassis(chassis_private):
         try:
             return chassis_private.chassis[0]
-        except (AttributeError, IndexError):
+        except AttributeError:
             # No Chassis_Private support, just use Chassis
             return chassis_private
+        except IndexError:
+            # Chassis register has been deleted but not Chassis_Private.
+            return DeletedChassis
 
     @property
     def updated_at(self):

neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/test_mech_driver.py

@@ -846,12 +846,12 @@ class AgentWaitEvent(event.WaitEvent):
 
     ONETIME = False
 
-    def __init__(self, driver, chassis_names):
+    def __init__(self, driver, chassis_names, events=None, timeout=None):
         table = driver.agent_chassis_table
-        events = (self.ROW_CREATE,)
+        events = events or (self.ROW_CREATE,)
         self.chassis_names = chassis_names
-        super().__init__(events, table, None)
-        self.event_name = 'AgentWaitEvent'
+        super().__init__(events, table, None, timeout=timeout)
+        self.event_name = "AgentWaitEvent"
 
     def match_fn(self, event, row, old):
         return row.name in self.chassis_names
@@ -909,6 +909,21 @@ class TestAgentApi(base.TestOVNFunctionalBase):
             self.context, filters={'host': self.host})]
         self.assertCountEqual(list(self.agent_types.values()), agent_ids)
 
+        # "ovn-controller" ends without deleting "Chassis" and
+        # "Chassis_Private" registers. If "Chassis" register is deleted,
+        # then Chassis_Private.chassis = []; both metadata and controller
+        # agents will still be present in the agent list.
+        agent_event = AgentWaitEvent(self.mech_driver, [self.chassis],
+                                     events=(event.RowEvent.ROW_UPDATE,),
+                                     timeout=1)
+        self.sb_api.idl.notify_handler.watch_event(agent_event)
+        self.sb_api.chassis_del(self.chassis, if_exists=True).execute(
+            check_error=False)
+        agent_event.wait()
+        agent_ids = [a['id'] for a in self.plugin.get_agents(
+            self.context, filters={'host': self.host})]
+        self.assertCountEqual(list(self.agent_types.values()), agent_ids)
+
 
 class ConnectionInactivityProbeSetEvent(event.WaitEvent):
     """Wait for a Connection (NB/SB) to have the inactivity probe set"""