Merge "add arp_responder flag to linuxbridge agent"

neutron/plugins/ml2/drivers/linuxbridge/agent/common/config.py

@@ -44,6 +44,12 @@ vxlan_opts = [
                 help=_("Extension to use alongside ml2 plugin's l2population "
                        "mechanism driver. It enables the plugin to populate "
                        "VXLAN forwarding table.")),
+    cfg.BoolOpt('arp_responder', default=False,
+                help=_("Enable local ARP responder which provides local "
+                       "responses instead of performing ARP broadcast into "
+                       "the overlay. Enabling local ARP responder is not fully"
+                       "compatible with the allowed-address-pairs extension.")
+                ),
 ]
 
 bridge_opts = [

neutron/plugins/ml2/drivers/linuxbridge/agent/linuxbridge_neutron_agent.py

@@ -270,7 +270,7 @@ class LinuxBridgeManager(amb.CommonAgentManagerBase):
             if cfg.CONF.VXLAN.tos:
                 args['tos'] = cfg.CONF.VXLAN.tos
             if cfg.CONF.VXLAN.l2_population:
-                args['proxy'] = True
+                args['proxy'] = cfg.CONF.VXLAN.arp_responder
             try:
                 int_vxlan = self.ip.add_vxlan(interface, segmentation_id,
                                               **args)

neutron/tests/unit/plugins/ml2/drivers/linuxbridge/agent/test_linuxbridge_neutron_agent.py

@@ -336,7 +336,7 @@ class TestLinuxBridgeManager(base.BaseTestCase):
                 add_vlan_fn.assert_called_with('eth0.1', 'eth0', '1')
                 dv6_fn.assert_called_once_with()
 
-    def test_ensure_vxlan(self):
+    def test_ensure_vxlan(self, expected_proxy=False):
         seg_id = "12345678"
         self.lbm.local_int = 'eth0'
         self.lbm.vxlan_mode = lconst.VXLAN_MCAST
@@ -360,7 +360,11 @@ class TestLinuxBridgeManager(base.BaseTestCase):
                 add_vxlan_fn.assert_called_with("vxlan-" + seg_id, seg_id,
                                                 group="224.0.0.1",
                                                 dev=self.lbm.local_int,
-                                                proxy=True)
+                                                proxy=expected_proxy)
+
+    def test_ensure_vxlan_arp_responder_enabled(self):
+        cfg.CONF.set_override('arp_responder', True, 'VXLAN')
+        self.test_ensure_vxlan(expected_proxy=True)
 
     def test_update_interface_ip_details(self):
         gwdict = dict(gateway='1.1.1.1',

releasenotes/notes/linuxbridge_vxlan_arp_responder-e9ea91552e1b62a7.yaml

@@ -0,0 +1,21 @@
+---
+upgrade:
+    When using ML2 and the Linux Bridge agent, the default value for the ARP
+    Responder under L2Population has changed. The responder is now disabled to
+    improve compatibility with the allowed-address-pair extension and to match
+    the default behavior of the ML2 OVS agent. The logical network will now
+    utilize traditional flood and learn through the overlay. When upgrading,
+    existing vxlan devices will retain their old setup and be unimpacted by
+    changes to this flag. To apply this to older devices created with the
+    Liberty agent, the vxlan device must be removed and then the Mitaka agent
+    restarted. The agent will recreate the vxlan devices with the current
+    settings upon restart. To maintain pre-Mitaka behavior, enable the
+    arp_responder in the Linux Bridge agent VXLAN config file prior to starting
+    the updated agent.
+
+fixes:
+    The Linuxbridge agent now supports the ability to toggle the local ARP
+    responder when L2Population is enabled. This ensures compatibility with
+    the allowed-address-pairs extension.
+  - closes bug 1445089
+