[OVN] DB sync host/physnet - filter on agent_type

When syncing hostname and physical networks, filter neutron
hosts on agent_type. Only segmenthostmappings for hosts
with agent 'OVN Controller agent' should be cleaned up.

Since change: I935186b6ee95f0cae8dc05869d9742c8fb3353c3 there
is de-duplication of segmenthostmapping updates from agents.
If the OVN DB sync clears/deletes mappings for hosts owned by
other agents/plugins the mappings are never re-created.

Closes-Bug: #2040172

Change-Id: Iaf15e560e1b1ec31618b2ebc6206a938463c1094
Signed-off-by: Harald Jensås <[email protected]>
(cherry picked from commit 3aafeef)

Author: hjensas

neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovn_db_sync.py

@@ -1353,7 +1353,8 @@ def sync_hostname_and_physical_networks(self, ctx):
         LOG.debug('OVN-SB Sync hostname and physical networks started')
         host_phynets_map = self.ovn_api.get_chassis_hostname_and_physnets()
         current_hosts = set(host_phynets_map)
-        previous_hosts = segments_db.get_hosts_mapped_with_segments(ctx)
+        previous_hosts = segments_db.get_hosts_mapped_with_segments(
+            ctx, include_agent_types={ovn_const.OVN_CONTROLLER_AGENT})
 
         stale_hosts = previous_hosts - current_hosts
         for host in stale_hosts:

neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_ovn_db_sync.py

@@ -1818,6 +1818,22 @@ def setUp(self):
     def _sync_resources(self):
         self.sb_synchronizer.sync_hostname_and_physical_networks(self.ctx)
 
+    def create_agent(self, host, bridge_mappings=None, agent_type=None):
+        if agent_type is None:
+            agent_type = ovn_const.OVN_CONTROLLER_AGENT
+        if bridge_mappings is None:
+            bridge_mappings = {}
+        agent = {
+            'host': host,
+            'agent_type': agent_type,
+            'binary': '/bin/test',
+            'topic': 'test_topic',
+            'configurations': {'bridge_mappings': bridge_mappings}
+        }
+        _, status = self.plugin.create_or_update_agent(self.context, agent)
+
+        return status['id']
+
     def create_segment(self, network_id, physical_network, segmentation_id):
         segment_data = {'network_id': network_id,
                         'physical_network': physical_network,
@@ -1858,6 +1874,7 @@ def test_ovn_sb_sync_delete_stale_host(self):
         segment = self.create_segment(network_id, 'physnet1', 50)
         segments_db.update_segment_host_mapping(
             self.ctx, 'host1', {segment['id']})
+        _ = self.create_agent('host1', bridge_mappings={'physnet1': 'eth0'})
         segment_hosts = segments_db.get_hosts_mapped_with_segments(self.ctx)
         self.assertEqual({'host1'}, segment_hosts)
         # Since there is no chassis in the sb DB, host1 is the stale host
@@ -1866,6 +1883,36 @@ def test_ovn_sb_sync_delete_stale_host(self):
         segment_hosts = segments_db.get_hosts_mapped_with_segments(self.ctx)
         self.assertFalse(segment_hosts)
 
+    def test_ovn_sb_sync_host_with_no_agent_not_deleted(self):
+        with self.network() as network:
+            network_id = network['network']['id']
+        segment = self.create_segment(network_id, 'physnet1', 50)
+        segments_db.update_segment_host_mapping(
+            self.ctx, 'host1', {segment['id']})
+        _ = self.create_agent('host1', bridge_mappings={'physnet1': 'eth0'},
+                              agent_type="Not OVN Agent")
+        segment_hosts = segments_db.get_hosts_mapped_with_segments(self.ctx)
+        self.assertEqual({'host1'}, segment_hosts)
+        # There is no chassis in the sb DB, host1 does not have an agent
+        # so it is not deleted.
+        self._sync_resources()
+        segment_hosts = segments_db.get_hosts_mapped_with_segments(self.ctx)
+        self.assertEqual({'host1'}, segment_hosts)
+
+    def test_ovn_sb_sync_host_with_other_agent_type_not_deleted(self):
+        with self.network() as network:
+            network_id = network['network']['id']
+        segment = self.create_segment(network_id, 'physnet1', 50)
+        segments_db.update_segment_host_mapping(
+            self.ctx, 'host1', {segment['id']})
+        segment_hosts = segments_db.get_hosts_mapped_with_segments(self.ctx)
+        self.assertEqual({'host1'}, segment_hosts)
+        # There is no chassis in the sb DB, host1 does not have an agent
+        # so it is not deleted.
+        self._sync_resources()
+        segment_hosts = segments_db.get_hosts_mapped_with_segments(self.ctx)
+        self.assertEqual({'host1'}, segment_hosts)
+
     def test_ovn_sb_sync(self):
         with self.network() as network:
             network_id = network['network']['id']
@@ -1878,6 +1925,9 @@ def test_ovn_sb_sync(self):
         segments_db.update_segment_host_mapping(
             self.ctx, 'host3', {seg1['id']})
         segment_hosts = segments_db.get_hosts_mapped_with_segments(self.ctx)
+        _ = self.create_agent('host1')
+        _ = self.create_agent('host2', bridge_mappings={'physnet2': 'eth0'})
+        _ = self.create_agent('host3', bridge_mappings={'physnet3': 'eth0'})
         self.assertEqual({'host1', 'host2', 'host3'}, segment_hosts)
         self.add_fake_chassis('host2', ['physnet2'])
         self.add_fake_chassis('host3', ['physnet3'])

neutron/tests/unit/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_ovn_db_sync.py

@@ -1169,8 +1169,10 @@ def test_ovn_sb_sync(self):
 
         with mock.patch.object(ovn_db_sync.segments_db,
                                'get_hosts_mapped_with_segments',
-                               return_value=hosts_in_neutron):
+                               return_value=hosts_in_neutron) as mock_ghmws:
             ovn_sb_synchronizer.sync_hostname_and_physical_networks(mock.ANY)
+            mock_ghmws.assert_called_once_with(
+                mock.ANY, include_agent_types={ovn_const.OVN_CONTROLLER_AGENT})
             all_hosts = set(hostname_with_physnets.keys()) | hosts_in_neutron
             self.assertEqual(
                 len(all_hosts),

releasenotes/notes/ovn-db-sync-host-physnet-filter-agent-type-9e22942bed304807.yaml

@@ -0,0 +1,10 @@
+---
+fixes:
+  - |
+    When synchronizing the OVN databases, either when running the migration
+    command or during startup, the code responsible for synchronization will
+    only clean up segment-to-host mappings for hosts with agent_type
+    ``OVN Controller agent``. Before, the synchronization would clean up
+    (delete) segment-to-host mappings for non-OVN hosts. Fixes bug:
+    `2040172 <https://bugs.launchpad.net/neutron/+bug/2040172>`_.
+