[OVN] Set mcast_flood_reports on LSPs

This patch enables the "mcast_flood_reports" and "mcast_flood" (on
provnet ports only) options in the Logical Switch Ports in the OVN driver.
Without these options, the ovn-controller will consume the IGMP queries
and won't send it to the LSP ports, meaning that external IGMP queries
will never arrive to the VMs.

In talks to the core OVN team, it was suggested [0] to enable the
"mcast_flood_reports" option by default in the OVN driver (at least until
fixed in core OVN) as a workaround to this problem. And, to avoid having
to update all ports (which can be many) based on the igmp_snooping_enable
configuration option, we are always setting "mcast_flood_reports" to
"true" in the LSPs. This won't cause any harm (also confirmed by core OVN
developers [0]) since it will be ignored if multicast snoop is disabled.

[0] https://bugzilla.redhat.com/show_bug.cgi?id=1933990#c3

(Manually cherry picked from Neutron b04d64b90f)

Closes-Bug: #1918108
Signed-off-by: Lucas Alvares Gomes <lucasagomes@gmail.com>
Change-Id: I63853f1b01c9b7444ed592c871a60125fa64f098

networking_ovn/common/constants.py

@@ -271,6 +271,8 @@ LSP_TYPE_VIRTUAL = 'virtual'
 LSP_TYPE_EXTERNAL = 'external'
 LSP_OPTIONS_VIRTUAL_PARENTS_KEY = 'virtual-parents'
 LSP_OPTIONS_VIRTUAL_IP_KEY = 'virtual-ip'
+LSP_OPTIONS_MCAST_FLOOD_REPORTS = 'mcast_flood_reports'
+LSP_OPTIONS_MCAST_FLOOD = 'mcast_flood'
 
 # OVN igmp options
 MCAST_SNOOP = 'mcast_snoop'

networking_ovn/common/maintenance.py

@@ -658,6 +658,34 @@ class DBInconsistenciesPeriodics(SchemaAwarePeriodicsBase):
                     txn.add(cmd)
         raise periodics.NeverAgain()
 
+    # TODO(lucasagomes): Remove this in the Y cycle
+    # A static spacing value is used here, but this method will only run
+    # once per lock due to the use of periodics.NeverAgain().
+    @periodics.periodic(spacing=600, run_immediately=True)
+    def check_for_mcast_flood_reports(self):
+        cmds = []
+        for port in self._nb_idl.lsp_list().execute(check_error=True):
+            port_type = port.type.strip()
+            if port_type in ("vtep", "localport", "router"):
+                continue
+
+            options = port.options
+            if ovn_const.LSP_OPTIONS_MCAST_FLOOD_REPORTS in options:
+                continue
+
+            options.update({ovn_const.LSP_OPTIONS_MCAST_FLOOD_REPORTS: 'true'})
+            if port_type == ovn_const.LSP_TYPE_LOCALNET:
+                options.update({ovn_const.LSP_OPTIONS_MCAST_FLOOD: 'true'})
+
+            cmds.append(self._nb_idl.lsp_set_options(port.name, **options))
+
+        if cmds:
+            with self._nb_idl.transaction(check_error=True) as txn:
+                for cmd in cmds:
+                    txn.add(cmd)
+
+        raise periodics.NeverAgain()
+
 
 class HashRingHealthCheckPeriodics(object):
 

networking_ovn/common/ovn_client.py

@@ -293,6 +293,14 @@ class OVNClient(object):
             options.update({'requested-chassis':
                             port.get(portbindings.HOST_ID, '')})
 
+        # TODO(lucasagomes): Enable the mcast_flood_reports by default,
+        # according to core OVN developers it shouldn't cause any harm
+        # and will be ignored when mcast_snoop is False. We can revise
+        # this once https://bugzilla.redhat.com/show_bug.cgi?id=1933990
+        # (see comment #3) is fixed in Core OVN.
+        if port_type not in ('vtep', 'localport', 'router'):
+            options.update({ovn_const.LSP_OPTIONS_MCAST_FLOOD_REPORTS: 'true'})
+
         device_owner = port.get('device_owner', '')
         sg_ids = ' '.join(utils.get_lsp_security_groups(port))
         return OvnPortInfo(port_type, options, addresses, port_security,
@@ -1561,6 +1569,9 @@ class OVNClient(object):
     def create_provnet_port(self, network_id, segment, txn=None):
         tag = segment.get(segment_def.SEGMENTATION_ID, [])
         physnet = segment.get(segment_def.PHYSICAL_NETWORK)
+        options = {'network_name': physnet,
+                   ovn_const.LSP_OPTIONS_MCAST_FLOOD_REPORTS: 'true',
+                   ovn_const.LSP_OPTIONS_MCAST_FLOOD: 'true'}
         cmd = self._nb_idl.create_lswitch_port(
             lport_name=utils.ovn_provnet_port_name(segment['id']),
             lswitch_name=utils.ovn_name(network_id),
@@ -1568,7 +1579,7 @@ class OVNClient(object):
             external_ids={},
             type=ovn_const.LSP_TYPE_LOCALNET,
             tag=tag,
-            options={'network_name': physnet})
+            options=options)
         self._transaction([cmd], txn=txn)
 
     def delete_provnet_port(self, network_id, segment):

networking_ovn/tests/functional/test_mech_driver.py

@@ -643,13 +643,11 @@ class TestProvnetPorts(base.TestOVNFunctionalBase):
         ovn_localnetport = self._find_port_row_by_name(
             utils.ovn_provnet_port_name(seg_db[0]['id']))
         self.assertEqual(ovn_localnetport.tag, [100])
-        self.assertEqual(ovn_localnetport.options,
-                         {'network_name': 'physnet1'})
+        self.assertEqual(ovn_localnetport.options['network_name'], 'physnet1')
         seg_2 = self.create_segment(n1['id'], 'physnet2', '222')
         ovn_localnetport = self._find_port_row_by_name(
             utils.ovn_provnet_port_name(seg_2['id']))
-        self.assertEqual(ovn_localnetport.options,
-                         {'network_name': 'physnet2'})
+        self.assertEqual(ovn_localnetport.options['network_name'], 'physnet2')
         self.assertEqual(ovn_localnetport.tag, [222])
 
         # Delete segments and ensure that localnet

networking_ovn/tests/unit/common/test_maintenance.py

@@ -395,3 +395,40 @@ class TestDBInconsistenciesPeriodics(db_base.DBTestCase,
                       priority=constants.HA_CHASSIS_GROUP_HIGHEST_PRIORITY - 1)
         ]
         nb_idl.ha_chassis_group_add_chassis.assert_has_calls(expected_calls)
+
+    def test_check_for_mcast_flood_reports(self):
+        nb_idl = self.fake_ovn_client._nb_idl
+        lsp0 = fakes.FakeOvsdbRow.create_one_ovsdb_row(
+            attrs={'name': 'lsp0',
+                   'options': {'mcast_flood_reports': 'true'},
+                   'type': ""})
+        lsp1 = fakes.FakeOvsdbRow.create_one_ovsdb_row(
+            attrs={'name': 'lsp1', 'options': {}, 'type': ""})
+        lsp2 = fakes.FakeOvsdbRow.create_one_ovsdb_row(
+            attrs={'name': 'lsp2', 'options': {},
+                   'type': "vtep"})
+        lsp3 = fakes.FakeOvsdbRow.create_one_ovsdb_row(
+            attrs={'name': 'lsp3', 'options': {},
+                   'type': "localport"})
+        lsp4 = fakes.FakeOvsdbRow.create_one_ovsdb_row(
+            attrs={'name': 'lsp4', 'options': {},
+                   'type': "router"})
+        lsp5 = fakes.FakeOvsdbRow.create_one_ovsdb_row(
+            attrs={'name': 'lsp5', 'options': {}, 'type': 'localnet'})
+
+        nb_idl.lsp_list.return_value.execute.return_value = [
+            lsp0, lsp1, lsp2, lsp3, lsp4, lsp5]
+
+        # Invoke the periodic method, it meant to run only once at startup
+        # so NeverAgain will be raised at the end
+        self.assertRaises(periodics.NeverAgain,
+                          self.periodic.check_for_mcast_flood_reports)
+
+        # Assert only lsp1 and lsp5 were called because they are the only
+        # ones meeting the criteria ("mcast_flood_reports" not yet set,
+        # and type "" or localnet)
+        expected_calls = [
+            mock.call('lsp1', mcast_flood_reports='true'),
+            mock.call('lsp5', mcast_flood_reports='true', mcast_flood='true')]
+
+        nb_idl.lsp_set_options.assert_has_calls(expected_calls)

networking_ovn/tests/unit/ml2/test_mech_driver.py

@@ -594,7 +594,9 @@ class TestOVNMechanismDriver(test_plugin.Ml2PluginV2TestCase):
             external_ids={},
             lport_name=ovn_utils.ovn_provnet_port_name(segments[0]['id']),
             lswitch_name=ovn_utils.ovn_name(net['id']),
-            options={'network_name': 'physnet1'},
+            options={'network_name': 'physnet1',
+                     ovn_const.LSP_OPTIONS_MCAST_FLOOD_REPORTS: 'true',
+                     ovn_const.LSP_OPTIONS_MCAST_FLOOD: 'true'},
             tag=2,
             type='localnet')
 
@@ -1957,7 +1959,9 @@ class TestOVNMechanismDriverSegment(test_segment.HostSegmentMappingTestCase):
             external_ids={},
             lport_name=ovn_utils.ovn_provnet_port_name(new_segment['id']),
             lswitch_name=ovn_utils.ovn_name(net['id']),
-            options={'network_name': 'phys_net1'},
+            options={'network_name': 'phys_net1',
+                     ovn_const.LSP_OPTIONS_MCAST_FLOOD_REPORTS: 'true',
+                     ovn_const.LSP_OPTIONS_MCAST_FLOOD: 'true'},
             tag=200,
             type='localnet')
         ovn_nb_api.create_lswitch_port.reset_mock()
@@ -1969,7 +1973,9 @@ class TestOVNMechanismDriverSegment(test_segment.HostSegmentMappingTestCase):
             external_ids={},
             lport_name=ovn_utils.ovn_provnet_port_name(new_segment['id']),
             lswitch_name=ovn_utils.ovn_name(net['id']),
-            options={'network_name': 'phys_net2'},
+            options={'network_name': 'phys_net2',
+                     ovn_const.LSP_OPTIONS_MCAST_FLOOD_REPORTS: 'true',
+                     ovn_const.LSP_OPTIONS_MCAST_FLOOD: 'true'},
             tag=300,
             type='localnet')
         segments = segments_db.get_network_segments(

releasenotes/notes/ovn-mcast-flood-reports-80fb529120f2af1c.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fixes a configuration problem in the OVN driver that prevented
+    external IGMP queries from reaching the Virtual Machines. See
+    `bug 1918108 <https://bugs.launchpad.net/neutron/+bug/1918108>`_
+    for details.