Add faults test which destroys and creates physical bridges

Test is destroying physical bridges on the node where router is
hosted so that floating IP shouldn't work at all.
Then it creates bridges again and checks if neutron-ovs-agent
was able to properly recover from that and FIP will work again.

Unfortunatelly this test can't work in e.g. devstack based u/s jobs
as there is additional bridge br-infra which provides connection between
nodes and this br-infra bridge is connected with br-ex by patch port.
When tobiko deletes br-ex and creates it again, there is this patch port
to br-infra missing and test is failing alwasy.

Test should works fine on deployments based on TripleO.

Change-Id: I125285f5f8abd2b2a285a7e46c954d6180d3ec32

tobiko/openstack/neutron/__init__.py

@@ -45,6 +45,7 @@ NoSuchNetwork = _client.NoSuchNetwork
 NoSuchPort = _client.NoSuchPort
 NoSuchRouter = _client.NoSuchRouter
 NoSuchSubnet = _client.NoSuchSubnet
+AgentNotFoundOnHost = _agent.AgentNotFoundOnHost
 
 new_ipv4_cidr = _cidr.new_ipv4_cidr
 new_ipv6_cidr = _cidr.new_ipv6_cidr

tobiko/openstack/neutron/_agent.py

@@ -17,6 +17,10 @@ import tobiko
 from tobiko.openstack.neutron import _client
 
 
+class AgentNotFoundOnHost(tobiko.TobikoException):
+    message = ("Agent {agent_type!s} not found on the host {host!s}")
+
+
 class NetworkingAgentFixture(tobiko.SharedFixture):
 
     client = None

tobiko/tests/faults/agents/test_neutron_agents.py

@@ -31,10 +31,6 @@ from tobiko.shell import sh
 LOG = log.getLogger(__name__)
 
 
-class AgentNotFoundOnHost(tobiko.TobikoException):
-    message = ("Agent {agent_type!s} not found on the host {host!s}")
-
-
 class AgentTestMixin(object):
 
     def stop_service_on_agents(self, service_name, agents):
@@ -350,8 +346,8 @@ class OvsAgentTest(testtools.TestCase, AgentTestMixin):
         for agent in self.ovs_agents:
             if host_shortname == tobiko.get_short_hostname(agent['host']):
                 return agent
-        raise AgentNotFoundOnHost(agent_type="neutron-ovs-agent",
-                                  host=host.name)
+        raise neutron.AgentNotFoundOnHost(agent_type="neutron-ovs-agent",
+                                          host=host.name)
 
     def test_vm_reachability_during_stop_ovs_agent(self):
         # Check if vm is reachable before test

tobiko/tests/faults/neutron/test_ovs.py

@@ -0,0 +1,91 @@
+# Copyright (c) 2020 Red Hat
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+from __future__ import absolute_import
+
+import collections
+
+import testtools
+
+import tobiko
+from tobiko.openstack import neutron
+from tobiko.openstack import stacks
+from tobiko.openstack import topology
+from tobiko.shell import ping
+from tobiko.shell import sh
+from tobiko.tripleo import undercloud
+
+
+@neutron.skip_if_missing_networking_agents(binary='neutron-openvswitch-agent')
+@neutron.skip_if_missing_networking_agents(binary='neutron-l3-agent')
+class OpenvswitchTest(testtools.TestCase):
+
+    stack = tobiko.required_setup_fixture(stacks.CirrosServerStackFixture)
+
+    def setUp(self):
+        super(OpenvswitchTest, self).setUp()
+        self.ovs_agents = neutron.list_agents(agent_type="Open vSwitch agent")
+        self.router_id = self.stack.network_stack.gateway_id
+
+        self.deleted_bridges = collections.defaultdict(set)
+
+    def tearDown(self):
+        super(OpenvswitchTest, self).tearDown()
+        # Try to create all bridges which were deleted during the tests
+        self._create_bridges()
+
+    def _create_bridges(self):
+        for host, bridges in self.deleted_bridges.items():
+            self._create_bridge(host, bridges)
+
+    def _create_bridge(self, hostname, bridges):
+        for br_name in bridges:
+            agent_host = topology.get_openstack_node(hostname=hostname)
+            sh.execute(
+                "sudo ovs-vsctl --may-exist add-br %s" % br_name,
+                ssh_client=agent_host.ssh_client)
+
+    def _delete_bridges(self, hostname, bridges):
+        for br_name in bridges:
+            agent_host = topology.get_openstack_node(hostname=hostname)
+            sh.execute(
+                "sudo ovs-vsctl del-br %s" % br_name,
+                ssh_client=agent_host.ssh_client)
+            self.deleted_bridges[hostname].add(br_name)
+
+    def _get_agent_from_host(self, hostname):
+        host_shortname = tobiko.get_short_hostname(hostname)
+        for agent in self.ovs_agents:
+            if host_shortname == tobiko.get_short_hostname(agent['host']):
+                return agent
+        raise neutron.AgentNotFoundOnHost(agent_type="neutron-ovs-agent",
+                                          host=hostname)
+
+    @undercloud.skip_if_missing_undercloud
+    def test_recreate_physical_bridge(self):
+        # Check if vm is reachable before test
+        ping.ping_until_received(self.stack.ip_address).assert_replied()
+
+        network_l3_agents = neutron.list_l3_agent_hosting_routers(
+            self.router_id)
+        for agent in network_l3_agents:
+            # Get neutron-ovs-agent bridge mappings
+            ovs_agent = self._get_agent_from_host(agent['host'])
+            self._delete_bridges(
+                agent['host'],
+                ovs_agent['configurations']['bridge_mappings'].values())
+
+        ping.ping_until_unreceived(self.stack.ip_address).assert_not_replied()
+        self._create_bridges()
+        ping.ping_until_received(self.stack.ip_address).assert_replied()