Monitor phys_bridges to reconfigured it if created again

In case when external bridge configured in OVS agent's bridge_mappings
will be destroyed and created again (for example by running ifup-ovs
script on Centos) bridge wasn't configured by OVS agent.
That might cause broken connectivity for OpenStack's dataplane if
dataplane network also uses same bridge.

This patch adds additional ovsdb-monitor to monitor if any
of physical bridges configured in bridge_mappings was created.
If so, agent will reconfigure it to restore proper openflow rules
on it.

Change-Id: I9c0dc587e70327e03be5a64522d0c679665f79bd
Closes-Bug: #1768990

neutron/agent/linux/ovsdb_monitor.py

@@ -12,6 +12,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import contextlib
+
+import eventlet
+from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_serialization import jsonutils
 
@@ -19,6 +23,7 @@ from neutron.agent.linux import async_process
 from neutron.agent.ovsdb import api as ovsdb
 from neutron.agent.ovsdb.native import helpers
 from neutron.common import utils
+from neutron.plugins.ml2.drivers.openvswitch.agent.common import constants
 
 
 LOG = logging.getLogger(__name__)
@@ -29,11 +34,28 @@ OVSDB_ACTION_DELETE = 'delete'
 OVSDB_ACTION_NEW = 'new'
 
 
+@contextlib.contextmanager
+def get_bridges_monitor(
+        bridges, ovsdb_monitor_respawn_interval=(
+            constants.DEFAULT_OVSDBMON_RESPAWN)):
+
+    mon = SimpleBridgesMonitor(
+        bridges,
+        respawn_interval=ovsdb_monitor_respawn_interval,
+        ovsdb_connection=cfg.CONF.OVS.ovsdb_connection)
+    mon.start()
+    try:
+        yield mon
+    finally:
+        mon.stop()
+
+
 class OvsdbMonitor(async_process.AsyncProcess):
     """Manages an invocation of 'ovsdb-client monitor'."""
 
     def __init__(self, table_name, columns=None, format=None,
                  respawn_interval=None, ovsdb_connection=None):
+        self.table_name = table_name
         if ovsdb_connection:
             # if ovsdb connection is configured (e.g. tcp:ip:port), use it,
             # and there is no need to run as root
@@ -51,6 +73,18 @@ class OvsdbMonitor(async_process.AsyncProcess):
                                            respawn_interval=respawn_interval,
                                            log_output=True,
                                            die_on_error=True)
+        self.new_events = {'added': [], 'removed': []}
+
+    def get_events(self):
+        self.process_events()
+        events = self.new_events
+        self.new_events = {'added': [], 'removed': []}
+        return events
+
+    def start(self, block=False, timeout=5):
+        super(OvsdbMonitor, self).start()
+        if block:
+            utils.wait_until_true(self.is_active)
 
 
 class SimpleInterfaceMonitor(OvsdbMonitor):
@@ -69,7 +103,6 @@ class SimpleInterfaceMonitor(OvsdbMonitor):
             respawn_interval=respawn_interval,
             ovsdb_connection=ovsdb_connection
         )
-        self.new_events = {'added': [], 'removed': []}
 
     @property
     def has_updates(self):
@@ -80,17 +113,11 @@ class SimpleInterfaceMonitor(OvsdbMonitor):
         temporary if respawn_interval is set.
         """
         if not self.is_active():
-            LOG.error("Interface monitor is not active")
+            LOG.error("%s monitor is not active", self.table_name)
         else:
             self.process_events()
         return bool(self.new_events['added'] or self.new_events['removed'])
 
-    def get_events(self):
-        self.process_events()
-        events = self.new_events
-        self.new_events = {'added': [], 'removed': []}
-        return events
-
     def process_events(self):
         devices_added = []
         devices_removed = []
@@ -118,7 +145,35 @@ class SimpleInterfaceMonitor(OvsdbMonitor):
         for event in self.new_events['added']:
             event['ofport'] = dev_to_ofport.get(event['name'], event['ofport'])
 
-    def start(self, block=False, timeout=5):
-        super(SimpleInterfaceMonitor, self).start()
-        if block:
-            utils.wait_until_true(self.is_active)
+
+class SimpleBridgesMonitor(OvsdbMonitor):
+    """Monitors the Bridge table of the local host's ovsdb for changes.
+
+    The bridges_added() method returns all newly created bridges in ovsdb
+    since the monitor started or since the previous access.
+    """
+
+    def __init__(self, bridges, respawn_interval=None, ovsdb_connection=None):
+        super(SimpleBridgesMonitor, self).__init__(
+            'Bridge',
+            columns=['name'],
+            format='json',
+            respawn_interval=respawn_interval,
+            ovsdb_connection=ovsdb_connection
+        )
+        self.bridges = bridges
+
+    @property
+    def bridges_added(self):
+        eventlet.sleep()
+        return self.get_events()['added']
+
+    def process_events(self):
+        bridges_added = []
+        for row in self.iter_stdout():
+            json = jsonutils.loads(row).get('data')
+            for ovs_id, action, name in json:
+                if name in self.bridges and action == OVSDB_ACTION_INSERT:
+                    bridges_added.append(name)
+
+        self.new_events['added'].extend(bridges_added)

neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py

@@ -47,6 +47,7 @@ from neutron.agent.common import ovs_lib
 from neutron.agent.common import polling
 from neutron.agent.common import utils
 from neutron.agent.l2 import l2_agent_extensions_manager as ext_manager
+from neutron.agent.linux import ovsdb_monitor
 from neutron.agent.linux import xenapi_root_helper
 from neutron.agent import rpc as agent_rpc
 from neutron.agent import securitygroups_rpc as agent_sg_rpc
@@ -750,7 +751,7 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
     def port_bound(self, port, net_uuid,
                    network_type, physical_network,
                    segmentation_id, fixed_ips, device_owner,
-                   ovs_restarted):
+                   provisioning_needed):
         '''Bind port to net_uuid/lsw_id and install flow for inbound traffic
         to vm.
 
@@ -761,9 +762,11 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
         :param segmentation_id: the VID for 'vlan' or tunnel ID for 'tunnel'
         :param fixed_ips: the ip addresses assigned to this port
         :param device_owner: the string indicative of owner of this port
-        :param ovs_restarted: indicates if this is called for an OVS restart.
+        :param provisioning_needed: indicates if this is called for an OVS
+                                    restart or recreated physical bridges
+                                    and requires to do local vlan provisioning
         '''
-        if net_uuid not in self.vlan_manager or ovs_restarted:
+        if net_uuid not in self.vlan_manager or provisioning_needed:
             self.provision_local_vlan(net_uuid, network_type,
                                       physical_network, segmentation_id)
         lvm = self.vlan_manager.get(net_uuid)
@@ -1062,6 +1065,19 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
         self.tun_br.setup_default_table(self.patch_int_ofport,
                                         self.arp_responder_enabled)
 
+    def _reconfigure_physical_bridges(self, bridges):
+        sync = False
+        bridge_mappings = {}
+        for bridge in bridges:
+            LOG.info("Physical bridge %s was just re-created.", bridge)
+            for phys_net, phys_br in self.bridge_mappings.items():
+                if bridge == phys_br:
+                    bridge_mappings[phys_net] = bridge
+        if bridge_mappings:
+            sync = True
+            self.setup_physical_bridges(bridge_mappings)
+        return sync
+
     def setup_physical_bridges(self, bridge_mappings):
         '''Setup the physical network bridges.
 
@@ -1393,7 +1409,7 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
 
     def treat_vif_port(self, vif_port, port_id, network_id, network_type,
                        physical_network, segmentation_id, admin_state_up,
-                       fixed_ips, device_owner, ovs_restarted):
+                       fixed_ips, device_owner, provisioning_needed):
         # When this function is called for a port, the port should have
         # an OVS ofport configured, as only these ports were considered
         # for being treated. If that does not happen, it is a potential
@@ -1408,7 +1424,7 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
                 port_needs_binding = self.port_bound(
                     vif_port, network_id, network_type,
                     physical_network, segmentation_id,
-                    fixed_ips, device_owner, ovs_restarted)
+                    fixed_ips, device_owner, provisioning_needed)
             else:
                 LOG.info("VIF port: %s admin state up disabled, "
                          "putting on the dead VLAN", vif_port.vif_id)
@@ -1492,7 +1508,7 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
                     br.cleanup_tunnel_port(ofport)
                     self.tun_br_ofports[tunnel_type].pop(remote_ip, None)
 
-    def treat_devices_added_or_updated(self, devices, ovs_restarted):
+    def treat_devices_added_or_updated(self, devices, provisioning_needed):
         skipped_devices = []
         need_binding_devices = []
         devices_details_list = (
@@ -1530,7 +1546,7 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
                                                    details['admin_state_up'],
                                                    details['fixed_ips'],
                                                    details['device_owner'],
-                                                   ovs_restarted)
+                                                   provisioning_needed)
                 if need_binding:
                     need_binding_devices.append(details)
                 self._update_port_network(details['port_id'],
@@ -1617,7 +1633,7 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
         if failed_devices:
             LOG.debug("Port down failed for %s", failed_devices)
 
-    def process_network_ports(self, port_info, ovs_restarted):
+    def process_network_ports(self, port_info, provisioning_needed):
         failed_devices = {'added': set(), 'removed': set()}
         # TODO(salv-orlando): consider a solution for ensuring notifications
         # are processed exactly in the same order in which they were
@@ -1639,7 +1655,7 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
             (skipped_devices, need_binding_devices,
             failed_devices['added']) = (
                 self.treat_devices_added_or_updated(
-                    devices_added_updated, ovs_restarted))
+                    devices_added_updated, provisioning_needed))
             LOG.debug("process_network_ports - iteration:%(iter_num)d - "
                       "treat_devices_added_or_updated completed. "
                       "Skipped %(num_skipped)d devices of "
@@ -1983,7 +1999,7 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
             polling_manager.stop()
             polling_manager.start()
 
-    def rpc_loop(self, polling_manager=None):
+    def rpc_loop(self, polling_manager=None, bridges_monitor=None):
         if not polling_manager:
             polling_manager = polling.get_polling_manager(
                 minimize_polling=False)
@@ -2005,6 +2021,7 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
                 LOG.info("rpc_loop doing a full sync.")
                 sync = True
                 self.fullsync = False
+            bridges_recreated = False
             port_info = {}
             ancillary_port_info = {}
             start = time.time()
@@ -2021,6 +2038,11 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
                 port_stats = self.get_port_stats({}, {})
                 self.loop_count_and_wait(start, port_stats)
                 continue
+            # Check if any physical bridge wasn't recreated recently
+            if bridges_monitor:
+                bridges_recreated = self._reconfigure_physical_bridges(
+                    bridges_monitor.bridges_added)
+                sync |= bridges_recreated
             # Notify the plugin of tunnel IP
             if self.enable_tunneling and tunnel_sync:
                 try:
@@ -2069,8 +2091,10 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
                         ovs_restarted):
                         LOG.debug("Starting to process devices in:%s",
                                   port_info)
+                        provisioning_needed = (
+                                ovs_restarted or bridges_recreated)
                         failed_devices = self.process_network_ports(
-                            port_info, ovs_restarted)
+                            port_info, provisioning_needed)
                         if need_clean_stale_flow:
                             self.cleanup_stale_flows()
                             need_clean_stale_flow = False
@@ -2115,11 +2139,15 @@ class OVSNeutronAgent(l2population_rpc.L2populationRpcCallBackTunnelMixin,
         signal.signal(signal.SIGTERM, self._handle_sigterm)
         if hasattr(signal, 'SIGHUP'):
             signal.signal(signal.SIGHUP, self._handle_sighup)
+        br_names = [br.br_name for br in self.phys_brs.values()]
         with polling.get_polling_manager(
-            self.minimize_polling,
-            self.ovsdb_monitor_respawn_interval) as pm:
+                self.minimize_polling,
+                self.ovsdb_monitor_respawn_interval) as pm,\
+            ovsdb_monitor.get_bridges_monitor(
+                br_names,
+                self.ovsdb_monitor_respawn_interval) as bm:
 
-            self.rpc_loop(polling_manager=pm)
+            self.rpc_loop(polling_manager=pm, bridges_monitor=bm)
 
     def _handle_sigterm(self, signum, frame):
         self.catch_sigterm = True

neutron/tests/fullstack/resources/environment.py

@@ -141,10 +141,10 @@ class Host(fixtures.Fixture):
                     agent_cfg_fixture.get_br_tun_name())).bridge
             self.connect_to_internal_network_via_tunneling()
         else:
-            br_phys = self.useFixture(
+            self.br_phys = self.useFixture(
                 net_helpers.OVSBridgeFixture(
                     agent_cfg_fixture.get_br_phys_name())).bridge
-            self.connect_to_internal_network_via_vlans(br_phys)
+            self.connect_to_internal_network_via_vlans(self.br_phys)
 
         self.ovs_agent = self.useFixture(
             process.OVSAgentFixture(

neutron/tests/fullstack/test_l3_agent.py

@@ -208,6 +208,22 @@ class TestLegacyL3Agent(TestL3Agent):
         # Verify north-south connectivity using ping6 to external_vm.
         vm.block_until_ping(external_vm.ipv6)
 
+        # Now let's remove and create again phys bridge and check connectivity
+        # once again
+        br_phys = self.environment.hosts[0].br_phys
+        br_phys.destroy()
+        br_phys.create()
+        self.environment.hosts[0].connect_to_internal_network_via_vlans(
+            br_phys)
+
+        # ping floating ip from external vm
+        external_vm.block_until_ping(fip['floating_ip_address'])
+
+        # Verify VM is able to reach the router interface.
+        vm.block_until_ping(vm.gateway_ipv6)
+        # Verify north-south connectivity using ping6 to external_vm.
+        vm.block_until_ping(external_vm.ipv6)
+
 
 class TestHAL3Agent(TestL3Agent):
 

neutron/tests/unit/plugins/ml2/drivers/openvswitch/agent/test_ovs_neutron_agent.py

@@ -1672,14 +1672,59 @@ class TestOvsNeutronAgent(object):
             self.agent.reclaim_local_vlan('net2')
             tun_br.delete_port.assert_called_once_with('gre-02020202')
 
-    def test_daemon_loop_uses_polling_manager(self):
+    def test_ext_br_recreated(self):
+        bridge_mappings = {'physnet0': 'br-ex0',
+                           'physnet1': 'br-ex1'}
+        ex_br_mocks = [mock.Mock(br_name='br-ex0'),
+                       mock.Mock(br_name='br-ex1')]
+        phys_bridges = {'physnet0': ex_br_mocks[0],
+                        'physnet1': ex_br_mocks[1]},
+        bm_mock = mock.Mock()
         with mock.patch(
-            'neutron.agent.common.polling.get_polling_manager') as mock_get_pm:
-            with mock.patch.object(self.agent, 'rpc_loop') as mock_loop:
-                self.agent.daemon_loop()
+            'neutron.agent.linux.ovsdb_monitor.get_bridges_monitor',
+            return_value=bm_mock),\
+                mock.patch.object(
+                    self.agent,
+                    'check_ovs_status',
+                    return_value=constants.OVS_NORMAL),\
+                mock.patch.object(
+                    self.agent,
+                    '_agent_has_updates',
+                    side_effect=TypeError('loop exit')),\
+                mock.patch.dict(
+                    self.agent.bridge_mappings, bridge_mappings, clear=True),\
+                mock.patch.dict(
+                    self.agent.phys_brs, phys_bridges, clear=True),\
+                mock.patch.object(
+                    self.agent,
+                    'setup_physical_bridges') as setup_physical_bridges:
+            bm_mock.bridges_added = ['br-ex0']
+            try:
+                self.agent.rpc_loop(polling_manager=mock.Mock(),
+                                    bridges_monitor=bm_mock)
+            except TypeError:
+                pass
+        setup_physical_bridges.assert_called_once_with(
+            {'physnet0': 'br-ex0'})
+
+    def test_daemon_loop_uses_polling_manager(self):
+        ex_br_mock = mock.Mock(br_name="br-ex0")
+        with mock.patch(
+            'neutron.agent.common.polling.get_polling_manager'
+        ) as mock_get_pm, mock.patch(
+            'neutron.agent.linux.ovsdb_monitor.get_bridges_monitor'
+        ) as mock_get_bm, mock.patch.object(
+            self.agent, 'rpc_loop'
+        ) as mock_loop, mock.patch.dict(
+            self.agent.phys_brs, {'physnet0': ex_br_mock}, clear=True):
+
+            self.agent.daemon_loop()
         mock_get_pm.assert_called_with(True,
                                        constants.DEFAULT_OVSDBMON_RESPAWN)
-        mock_loop.assert_called_once_with(polling_manager=mock.ANY)
+        mock_get_bm.assert_called_once_with(
+            ['br-ex0'], constants.DEFAULT_OVSDBMON_RESPAWN)
+        mock_loop.assert_called_once_with(
+            polling_manager=mock.ANY, bridges_monitor=mock.ANY)
 
     def test_setup_tunnel_port_invalid_ofport(self):
         remote_ip = '1.2.3.4'