[OVN] The OVN agent should handle its own tags and status

The OVN agent should handle its own tags, written in the
"Chassis_Private.external_ids" dictionary. These are:
* neutron:ovn-neutron-agent-sb-cfg
* neutron:description-neutron-agent
* neutron:ovn-neutron-agent-id

The "metadata" extension should not create nor update these tags.
This patch removes from the "metadata" extension the
``SbGlobalUpdateEvent`` and ``ChassisPrivateCreateEvent`` events.

Partial-Bug: #2119097
Signed-off-by: Rodolfo Alonso Hernandez <ralonsoh@redhat.com>
Change-Id: I7f0ecf8f8727e363d98e981948c999305ae33426

neutron/agent/ovn/agent/ovn_neutron_agent.py

@@ -49,6 +49,32 @@ class SbGlobalUpdateEvent(row_event.RowEvent):
                                      ('external_ids', ext_ids)).execute()
 
 
+class ChassisPrivateCreateEvent(row_event.RowEvent):
+    """Row create event - Chassis name == our_chassis.
+
+    On connection, we get a dump of all chassis so if we catch a creation
+    of our own chassis it has to be a reconnection. In this case, we need
+    to do a full sync to make sure that we capture all changes while the
+    connection to OVSDB was down.
+    """
+    def __init__(self, ovn_agent):
+        self._first_time = True
+        self.ovn_agent = ovn_agent
+        events = (self.ROW_CREATE,)
+        super().__init__(events, 'Chassis_Private', None)
+        self.conditions = (('name', '=', self.ovn_agent.chassis),)
+        self.event_name = self.__class__.__name__
+
+    def run(self, event, row, old):
+        if self._first_time:
+            self._first_time = False
+            return
+
+        # Re-register the OVN agent with the local chassis in case its
+        # entry was re-created (happens when restarting the ovn-controller)
+        self.ovn_agent.register_ovn_agent()
+
+
 class OVNNeutronAgent(service.Service):
 
     def __init__(self, conf):
@@ -139,7 +165,9 @@ class OVNNeutronAgent(service.Service):
         return ovsdb.MonitorAgentOvnNbIdl(tables, events).start()
 
     def _load_sb_idl(self):
-        events = [SbGlobalUpdateEvent]
+        events = [SbGlobalUpdateEvent,
+                  ChassisPrivateCreateEvent,
+                  ]
         tables = ['SB_Global', 'Chassis_Private']
         for extension in self.ext_manager:
             events += extension.obj.sb_idl_events

neutron/agent/ovn/extensions/extension_manager.py

@@ -19,6 +19,7 @@ import threading
 from neutron_lib.agent import extension
 from neutron_lib import exceptions
 from oslo_log import log as logging
+from oslo_service import service
 
 from neutron._i18n import _
 from neutron.agent import agent_extensions_manager as agent_ext_mgr
@@ -33,6 +34,35 @@ class ConfigException(exceptions.NeutronException):
     message = _('Error configuring the OVN Neutron Agent: %(description)s.')
 
 
+class OVNExtensionEvent(metaclass=abc.ABCMeta):
+    """Implements a method to retrieve the correct caller agent
+
+    The events inheriting from this class could be called from the OVN metadata
+    agent or as part of an extension of the OVN agent ("metadata" extension,
+    for example). In future releases, the OVN metadata agent will be superseded
+    by the OVN agent (with the "metadata" extension) and this class removed,
+    keeping only the compatibility with the OVN agent (to be removed in C+2).
+    """
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._agent_or_extension = None
+        self._agent = None
+
+    @property
+    def agent(self):
+        """This method provide support for the OVN agent
+
+        This event can be used in the OVN metadata agent and in the OVN
+        agent metadata extension.
+        """
+        if not self._agent_or_extension:
+            if isinstance(self._agent, service.Service):
+                self._agent_or_extension = self._agent['metadata']
+            else:
+                self._agent_or_extension = self._agent
+        return self._agent_or_extension
+
+
 class OVNAgentExtensionManager(agent_ext_mgr.AgentExtensionsManager):
 
     def __init__(self, conf):

neutron/agent/ovn/extensions/metadata.py

@@ -115,8 +115,6 @@ class MetadataExtension(extension_manager.OVNAgentExtension,
     def sb_idl_events(self):
         return [metadata_agent.PortBindingUpdatedEvent,
                 metadata_agent.PortBindingDeletedEvent,
-                metadata_agent.SbGlobalUpdateEvent,
-                metadata_agent.ChassisPrivateCreateEvent,
                 ]
 
     # NOTE(ralonsoh): the following properties are needed during the migration
@@ -162,7 +160,6 @@ class MetadataExtension(extension_manager.OVNAgentExtension,
         """
         self.agent_api.load_config()
         self._update_chassis_private_config()
-        self.agent_api.update_neutron_sb_cfg_key()
         self.sync()
 
     def start(self):

neutron/agent/ovn/metadata/agent.py

@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import abc
 import collections
 import functools
 import re
@@ -31,7 +30,7 @@ from ovsdbapp.backend.ovs_idl import vlog
 from neutron.agent.linux import external_process
 from neutron.agent.linux import ip_lib
 from neutron.agent.linux import iptables_manager
-from neutron.agent.ovn.agent import ovn_neutron_agent
+from neutron.agent.ovn.extensions import extension_manager
 from neutron.agent.ovn.metadata import driver as metadata_driver
 from neutron.agent.ovn.metadata import ovsdb
 from neutron.agent.ovn.metadata import server_socket as metadata_server
@@ -87,36 +86,8 @@ class ConfigException(Exception):
     """
 
 
-class _OVNExtensionEvent(metaclass=abc.ABCMeta):
+class PortBindingEvent(extension_manager.OVNExtensionEvent,
-    """Implements a method to retrieve the correct caller agent
+                       row_event.RowEvent):
-
-    The events inheriting from this class could be called from the OVN metadata
-    agent or as part of an extension of the OVN agent ("metadata" extension,
-    for example). In future releases, the OVN metadata agent will be superseded
-    by the OVN agent (with the "metadata" extension) and this class removed,
-    keeping only the compatibility with the OVN agent (to be removed in C+2).
-    """
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-        self._agent_or_extension = None
-        self._agent = None
-
-    @property
-    def agent(self):
-        """This method provide support for the OVN agent
-
-        This event can be used in the OVN metadata agent and in the OVN
-        agent metadata extension.
-        """
-        if not self._agent_or_extension:
-            if isinstance(self._agent, ovn_neutron_agent.OVNNeutronAgent):
-                self._agent_or_extension = self._agent['metadata']
-            else:
-                self._agent_or_extension = self._agent
-        return self._agent_or_extension
-
-
-class PortBindingEvent(_OVNExtensionEvent, row_event.RowEvent):
     def __init__(self, agent):
         table = 'Port_Binding'
         super().__init__((self.__class__.EVENT,), table, None)
@@ -301,7 +272,7 @@ class PortBindingDeletedEvent(PortBindingEvent):
         return True
 
 
-class ChassisPrivateCreateEvent(_OVNExtensionEvent, row_event.RowEvent):
+class ChassisPrivateCreateEvent(row_event.RowEvent):
     """Row create event - Chassis name == our_chassis.
 
     On connection, we get a dump of all chassis so if we catch a creation
@@ -314,9 +285,7 @@ class ChassisPrivateCreateEvent(_OVNExtensionEvent, row_event.RowEvent):
         self.first_time = True
         events = (self.ROW_CREATE,)
         super().__init__(events, 'Chassis_Private', None)
-        # NOTE(ralonsoh): ``self._agent`` needs to be assigned before being
+        self.agent = agent
-        # used in the property ``self.agent``.
-        self._agent = agent
         self.conditions = (('name', '=', self.agent.chassis),)
         self.event_name = self.__class__.__name__
 
@@ -332,14 +301,14 @@ class ChassisPrivateCreateEvent(_OVNExtensionEvent, row_event.RowEvent):
             self.agent.sync()
 
 
-class SbGlobalUpdateEvent(_OVNExtensionEvent, row_event.RowEvent):
+class SbGlobalUpdateEvent(row_event.RowEvent):
     """Row update event on SB_Global table."""
 
     def __init__(self, agent):
         table = 'SB_Global'
         events = (self.ROW_UPDATE,)
         super().__init__(events, table, None)
-        self._agent = agent
+        self.agent = agent
         self.event_name = self.__class__.__name__
         self.first_run = True
 

neutron/tests/functional/agent/ovn/agent/test_ovn_neutron_agent.py

@@ -18,6 +18,7 @@ import uuid
 
 from oslo_config import fixture as fixture_config
 from oslo_utils import uuidutils
+from ovsdbapp.backend.ovs_idl import idlutils
 
 from neutron.agent.ovn.agent import ovn_neutron_agent
 from neutron.agent.ovn.agent import ovsdb as agent_ovsdb
@@ -94,6 +95,29 @@ class TestOVNNeutronAgentBase(base.TestOVNFunctionalBase):
         return agt
 
 
+class TestOVNNeutronAgent(TestOVNNeutronAgentBase):
+    def setUp(self, **kwargs):
+        super().setUp(extensions=[METADATA_EXTENSION], **kwargs)
+
+    def test_chassis_private_create_event(self):
+        def _check_chassis_private():
+            try:
+                ext_ids = self.ovn_agent.sb_idl.db_get(
+                    'Chassis_Private', self.chassis_name,
+                    'external_ids').execute(check_error=True)
+                return (ext_ids.get(ovn_const.OVN_AGENT_NEUTRON_ID_KEY)
+                        is not None)
+            except idlutils.RowNotFound:
+                return False
+
+        # If the "Chassis_Private" register is deleted and created again,
+        # the agent should be able to re-register itself.
+        self.ovn_agent.sb_idl.chassis_del(self.chassis_name).execute(
+            check_error=True)
+        self.add_fake_chassis(self.host_name, name=self.chassis_name)
+        n_utils.wait_until_true(_check_chassis_private, timeout=10)
+
+
 class TestOVNNeutronAgentFakeAgent(TestOVNNeutronAgentBase):
 
     def setUp(self, **kwargs):