Fix using host_routes in VIP subnet with amphorav2

Ensure that amphorae_network_config parameter is not modified in
AmphoraPostVIPPlug. Modifying it would break amphorav2 persistence by
introducing non-serializable elements in the subnet dict

Story: 2008955
Task: 42580

Change-Id: I8f0d3ba1d083c7e37e7e26617826400a538a0890

octavia/controller/worker/v2/tasks/amphora_driver_tasks.py

@@ -13,6 +13,7 @@
 # under the License.
 #
 
+import copy
 from cryptography import fernet
 from oslo_config import cfg
 from oslo_log import log as logging
@@ -334,8 +335,9 @@ class AmphoraPostVIPPlug(BaseAmphoraTask):
             **amphorae_network_config[
                 amphora.get(constants.ID)][constants.VRRP_PORT])
         # Required for noop-case
-        vip_arg = amphorae_network_config[amphora.get(
-            constants.ID)][constants.VIP_SUBNET]
+        vip_arg = copy.deepcopy(
+            amphorae_network_config[
+                amphora.get(constants.ID)][constants.VIP_SUBNET])
         if vip_arg:
             host_routes = vip_arg.get('host_routes')
             if host_routes:

octavia/tests/unit/controller/worker/v2/tasks/test_amphora_driver_tasks.py

@@ -630,6 +630,11 @@ class TestAmphoraDriverTasks(base.TestCase):
             self.assertEqual(hr1['destination'], hr2.destination)
             self.assertEqual(hr1['nexthop'], hr2.nexthop)
 
+        self.assertEqual(
+            host_routes,
+            amphorae_net_config_mock[AMP_ID][
+                constants.VIP_SUBNET]['host_routes'])
+
     @mock.patch('octavia.db.repositories.LoadBalancerRepository.update')
     @mock.patch('octavia.db.repositories.LoadBalancerRepository.get')
     def test_amphorae_post_vip_plug(self, mock_lb_get,

releasenotes/notes/fix-host-routes-with-amphorav2-and-persistence-54b99d651a4ee9c4.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fix a serialization error when using host_routes in VIP subnets when
+    persistence in the amphorav2 driver is enabled.