Handle several dhcp agents for metadata over ipv6

[0] added the capability to the dhcp agent of handling metadata traffic
over ipv6. However, the added code doesn't handle the case when a
network is managed by more than one dhcp agent. This change fixes the
issue.

[0] https://review.opendev.org/c/openstack/neutron/+/715482

Change-Id: Ie1e0739f2c7390031af196e72c678ee626d0f8b8
Closes-Bug: #1989979
(cherry picked from commit 41a7479)

Author: Miguel Lavalle

neutron/agent/dhcp/agent.py

@@ -753,7 +753,7 @@ def enable_isolated_metadata_proxy(self, network):
                         'get_metadata_bind_interface', network, port=p)
                     for p in network.ports
                     if (p.device_owner == constants.DEVICE_OWNER_DHCP and
-                        p.admin_state_up)
+                        p.admin_state_up and self._is_port_on_this_agent(p))
                 ]
                 if len(dhcp_ifaces) == 1:
                     kwargs['bind_interface'] = dhcp_ifaces[0]

neutron/tests/unit/agent/dhcp/test_agent.py

@@ -1088,18 +1088,38 @@ def _test_enable_isolated_metadata_proxy_ipv6(self, network):
 
     def test_enable_isolated_metadata_proxy_with_metadata_network_ipv6(self):
         network = copy.deepcopy(fake_meta_network)
-        network.ports = [fake_dhcp_port]
+        dhcp_port_this_host = copy.deepcopy(fake_dhcp_port)
+        dhcp_port_this_host.device_id = utils.get_dhcp_agent_device_id(
+            network.id, self.dhcp.conf.host)
+        network.ports = [dhcp_port_this_host]
         self._test_enable_isolated_metadata_proxy_ipv6(network)
 
     def test_enable_isolated_metadata_proxy_with_metadata_network_dvr_ipv6(
             self):
         network = copy.deepcopy(fake_meta_dvr_network)
-        network.ports = [fake_dhcp_port]
+        dhcp_port_this_host = copy.deepcopy(fake_dhcp_port)
+        dhcp_port_this_host.device_id = utils.get_dhcp_agent_device_id(
+            network.id, self.dhcp.conf.host)
+        network.ports = [dhcp_port_this_host]
         self._test_enable_isolated_metadata_proxy_ipv6(network)
 
     def test_enable_isolated_metadata_proxy_with_dist_network_ipv6(self):
         network = copy.deepcopy(fake_dist_network)
-        network.ports = [fake_dhcp_port]
+        dhcp_port_this_host = copy.deepcopy(fake_dhcp_port)
+        dhcp_port_this_host.device_id = utils.get_dhcp_agent_device_id(
+            network.id, self.dhcp.conf.host)
+        network.ports = [dhcp_port_this_host]
+        self._test_enable_isolated_metadata_proxy_ipv6(network)
+
+    def test_enable_isolated_metadata_proxy_with_2_agents_network_ipv6(self):
+        network = copy.deepcopy(fake_meta_network)
+        dhcp_port_this_host = copy.deepcopy(fake_dhcp_port)
+        dhcp_port_this_host.device_id = utils.get_dhcp_agent_device_id(
+            network.id, self.dhcp.conf.host)
+        dhcp_port_other_host = copy.deepcopy(fake_dhcp_port)
+        dhcp_port_other_host.device_id = utils.get_dhcp_agent_device_id(
+            network.id, 'otherhostname')
+        network.ports = [dhcp_port_this_host, dhcp_port_other_host]
         self._test_enable_isolated_metadata_proxy_ipv6(network)
 
     def _test_disable_isolated_metadata_proxy(self, network):