automatic discovery of the network node trunk ID via OVN Gateway agent.

Previously, the network node trunk ID had to be manually configured in ml2 config. This had operational overhead and made the system less flexible when underling nodes used to deploy neutron is changed.

Author: syedhaseebahmed

python/neutron-understack/neutron_understack/config.py

@@ -50,13 +50,6 @@
             "is used to trunk all vlans used by a neutron router."
         ),
     ),
-    cfg.StrOpt(
-        "network_node_trunk_uuid",
-        help=(
-            "UUID of the trunk that is used to trunk all vlans used by a Neutron"
-            " router."
-        ),
-    ),
     cfg.StrOpt(
         "network_node_switchport_physnet",
         help=(

python/neutron-understack/neutron_understack/ironic.py

@@ -32,3 +32,10 @@ def _port_by_local_link(self, local_link_info: dict) -> BaremetalPort | None:
             )
         except StopIteration:
             return None
+
+    def baremetal_node_name(self, node_uuid: str) -> str | None:
+        try:
+            node = self.irclient.get_node(node_uuid)
+            return node.name if node else None
+        except Exception:
+            return None

python/neutron-understack/neutron_understack/routers.py

@@ -98,9 +98,11 @@ def add_subport_to_trunk(shared_port: PortDict, segment: NetworkSegmentDict) ->
             },
         ]
     }
+    trunk_id = utils.fetch_network_node_trunk_id()
+
     utils.fetch_trunk_plugin().add_subports(
         context=n_context.get_admin_context(),
-        trunk_id=cfg.CONF.ml2_understack.network_node_trunk_uuid,
+        trunk_id=trunk_id,
         subports=subports,
     )
 
@@ -251,8 +253,7 @@ def handle_router_interface_removal(_resource, _event, trigger, payload) -> None
 
 def handle_subport_removal(port: Port) -> None:
     """Removes router's subport from a network node trunk."""
-    # trunk_id will be discovered dynamically at some point
-    trunk_id = cfg.CONF.ml2_understack.network_node_trunk_uuid
+    trunk_id = utils.fetch_network_node_trunk_id()
     LOG.debug("Router, Removing subport: %s(port)s", {"port": port})
     port_id = port["id"]
     try:

python/neutron-understack/neutron_understack/tests/test_routers.py

@@ -37,8 +37,8 @@ def test_when_successful(self, mocker):
         port = {"id": "port-123"}
         segment = {"segmentation_id": 42}
         mocker.patch(
-            "oslo_config.cfg.CONF.ml2_understack.network_node_trunk_uuid",
-            trunk_id,
+            "neutron_understack.utils.fetch_network_node_trunk_id",
+            return_value=trunk_id,
         )
         mocker.patch(
             "neutron_lib.context.get_admin_context", return_value="admin_context"
@@ -70,7 +70,8 @@ def test_when_successful(self, mocker):
 class TestHandleSubportRemoval:
     def test_when_successful(self, mocker, port_id, trunk_id):
         mocker.patch(
-            "oslo_config.cfg.CONF.ml2_understack.network_node_trunk_uuid", str(trunk_id)
+            "neutron_understack.utils.fetch_network_node_trunk_id",
+            return_value=str(trunk_id),
         )
         mock_remove = mocker.patch("neutron_understack.utils.remove_subport_from_trunk")
         port = {"id": str(port_id)}

python/neutron-understack/neutron_understack/tests/test_trunk.py

@@ -336,13 +336,13 @@ class TestCheckSubportsSegmentationId:
     def test_when_trunk_id_is_network_node_trunk_id(
         self,
         mocker,
-        oslo_config,
         understack_trunk_driver,
         trunk_id,
     ):
-        oslo_config.config(
-            network_node_trunk_uuid=str(trunk_id),
-            group="ml2_understack",
+        # Mock fetch_network_node_trunk_id to return the trunk_id
+        mocker.patch(
+            "neutron_understack.utils.fetch_network_node_trunk_id",
+            return_value=str(trunk_id),
         )
         # Mock to ensure the function returns early and doesn't call this
         allowed_ranges_mock = mocker.patch(
@@ -362,6 +362,11 @@ def test_when_segmentation_id_is_in_allowed_range(
         trunk_id,
         subport,
     ):
+        # Mock fetch_network_node_trunk_id to return a different trunk ID
+        mocker.patch(
+            "neutron_understack.utils.fetch_network_node_trunk_id",
+            return_value="different-trunk-id",
+        )
         allowed_ranges = mocker.patch(
             "neutron_understack.utils.allowed_tenant_vlan_id_ranges",
             return_value=[(1, 1500)],
@@ -380,6 +385,11 @@ def test_when_segmentation_id_is_not_in_allowed_range(
         trunk_id,
         subport,
     ):
+        # Mock fetch_network_node_trunk_id to return a different trunk ID
+        mocker.patch(
+            "neutron_understack.utils.fetch_network_node_trunk_id",
+            return_value="different-trunk-id",
+        )
         mocker.patch(
             "neutron_understack.utils.allowed_tenant_vlan_id_ranges",
             return_value=[(1, 1500)],

python/neutron-understack/neutron_understack/tests/test_utils.py

@@ -1,3 +1,4 @@
+from unittest.mock import MagicMock
 from unittest.mock import patch
 
 import pytest
@@ -236,3 +237,281 @@ def test_single_range(
         expected_result = [(1, 499), (701, 2000)]
         result = utils.allowed_tenant_vlan_id_ranges()
         assert result == expected_result
+
+
+class TestIsUuid:
+    def test_valid_uuid(self):
+        assert utils._is_uuid("7ca98881-bca5-4c82-9369-66eb36292a95") is True
+
+    def test_invalid_uuid(self):
+        assert utils._is_uuid("not-a-uuid") is False
+
+    def test_hostname(self):
+        assert utils._is_uuid("1327172-hp1") is False
+
+    def test_empty_string(self):
+        assert utils._is_uuid("") is False
+
+
+class TestFetchNetworkNodeTrunkId:
+    @pytest.fixture(autouse=True)
+    def reset_cache(self):
+        """Reset the cache before each test."""
+        utils._cached_network_node_trunk_id = None
+        yield
+        utils._cached_network_node_trunk_id = None
+
+    def test_successful_discovery_with_hostname(self, mocker):
+        """Test successful trunk discovery when gateway host is a hostname."""
+        # Mock context and plugin
+        mock_context = MagicMock()
+        mock_plugin = MagicMock()
+
+        mocker.patch("neutron_lib.context.get_admin_context", return_value=mock_context)
+        mocker.patch("neutron_lib.plugins.directory.get_plugin", return_value=mock_plugin)
+
+        # Mock gateway agent with hostname
+        mock_plugin.get_agents.return_value = [
+            {"host": "gateway-host-1", "id": "agent-1"}
+        ]
+
+        # Mock port with binding
+        mock_port = MagicMock()
+        mock_port.id = "port-123"
+        mock_port.bindings = [MagicMock(host="gateway-host-1")]
+
+        mocker.patch(
+            "neutron.objects.ports.Port.get_objects", return_value=[mock_port]
+        )
+
+        # Mock trunk
+        mock_trunk = MagicMock()
+        mock_trunk.id = "trunk-456"
+        mock_trunk.port_id = "port-123"
+
+        mocker.patch(
+            "neutron.objects.trunk.Trunk.get_objects", return_value=[mock_trunk]
+        )
+
+        result = utils.fetch_network_node_trunk_id()
+
+        assert result == "trunk-456"
+        assert utils._cached_network_node_trunk_id == "trunk-456"
+
+    def test_successful_discovery_with_uuid(self, mocker):
+        """Test successful trunk discovery when gateway host is a UUID."""
+        mock_context = MagicMock()
+        mock_plugin = MagicMock()
+
+        mocker.patch("neutron_lib.context.get_admin_context", return_value=mock_context)
+        mocker.patch("neutron_lib.plugins.directory.get_plugin", return_value=mock_plugin)
+
+        # Mock gateway agent with UUID
+        gateway_uuid = "7ca98881-bca5-4c82-9369-66eb36292a95"
+        mock_plugin.get_agents.return_value = [{"host": gateway_uuid, "id": "agent-1"}]
+
+        # Mock Ironic client
+        mock_ironic = MagicMock()
+        mock_ironic.baremetal_node_name.return_value = "gateway-host-1"
+        mocker.patch(
+            "neutron_understack.utils.IronicClient", return_value=mock_ironic
+        )
+
+        # Mock port bound to UUID
+        mock_port = MagicMock()
+        mock_port.id = "port-123"
+        mock_port.bindings = [MagicMock(host=gateway_uuid)]
+
+        mocker.patch(
+            "neutron.objects.ports.Port.get_objects", return_value=[mock_port]
+        )
+
+        # Mock trunk
+        mock_trunk = MagicMock()
+        mock_trunk.id = "trunk-456"
+        mock_trunk.port_id = "port-123"
+
+        mocker.patch(
+            "neutron.objects.trunk.Trunk.get_objects", return_value=[mock_trunk]
+        )
+
+        result = utils.fetch_network_node_trunk_id()
+
+        assert result == "trunk-456"
+        mock_ironic.baremetal_node_name.assert_called_once_with(gateway_uuid)
+
+    def test_cache_returns_cached_value(self, mocker):
+        """Test that subsequent calls return cached value without querying."""
+        mock_context = MagicMock()
+        mock_plugin = MagicMock()
+
+        mocker.patch("neutron_lib.context.get_admin_context", return_value=mock_context)
+        mocker.patch("neutron_lib.plugins.directory.get_plugin", return_value=mock_plugin)
+
+        mock_plugin.get_agents.return_value = [
+            {"host": "gateway-host-1", "id": "agent-1"}
+        ]
+
+        mock_port = MagicMock()
+        mock_port.id = "port-123"
+        mock_port.bindings = [MagicMock(host="gateway-host-1")]
+
+        mock_get_objects = mocker.patch(
+            "neutron.objects.ports.Port.get_objects", return_value=[mock_port]
+        )
+
+        mock_trunk = MagicMock()
+        mock_trunk.id = "trunk-456"
+        mock_trunk.port_id = "port-123"
+
+        mocker.patch(
+            "neutron.objects.trunk.Trunk.get_objects", return_value=[mock_trunk]
+        )
+
+        # First call
+        result1 = utils.fetch_network_node_trunk_id()
+        assert result1 == "trunk-456"
+
+        # Second call should use cache
+        result2 = utils.fetch_network_node_trunk_id()
+        assert result2 == "trunk-456"
+
+        # Port.get_objects should only be called once (first call)
+        assert mock_get_objects.call_count == 1
+
+    def test_no_gateway_agents_found(self, mocker):
+        """Test exception when no alive gateway agents found."""
+        mock_context = MagicMock()
+        mock_plugin = MagicMock()
+
+        mocker.patch("neutron_lib.context.get_admin_context", return_value=mock_context)
+        mocker.patch("neutron_lib.plugins.directory.get_plugin", return_value=mock_plugin)
+
+        mock_plugin.get_agents.return_value = []
+
+        with pytest.raises(Exception, match="No alive OVN Controller Gateway agents"):
+            utils.fetch_network_node_trunk_id()
+
+    def test_no_core_plugin(self, mocker):
+        """Test exception when core plugin is not available."""
+        mock_context = MagicMock()
+
+        mocker.patch("neutron_lib.context.get_admin_context", return_value=mock_context)
+        mocker.patch("neutron_lib.plugins.directory.get_plugin", return_value=None)
+
+        with pytest.raises(Exception, match="Unable to obtain core plugin"):
+            utils.fetch_network_node_trunk_id()
+
+    def test_ironic_resolution_fails(self, mocker):
+        """Test exception when Ironic fails to resolve UUID."""
+        mock_context = MagicMock()
+        mock_plugin = MagicMock()
+
+        mocker.patch("neutron_lib.context.get_admin_context", return_value=mock_context)
+        mocker.patch("neutron_lib.plugins.directory.get_plugin", return_value=mock_plugin)
+
+        gateway_uuid = "7ca98881-bca5-4c82-9369-66eb36292a95"
+        mock_plugin.get_agents.return_value = [{"host": gateway_uuid, "id": "agent-1"}]
+
+        mock_ironic = MagicMock()
+        mock_ironic.baremetal_node_name.return_value = None
+        mocker.patch(
+            "neutron_understack.utils.IronicClient", return_value=mock_ironic
+        )
+
+        with pytest.raises(Exception, match="Failed to resolve baremetal node UUID"):
+            utils.fetch_network_node_trunk_id()
+
+    def test_no_ports_bound_to_gateway(self, mocker):
+        """Test exception when no ports are bound to gateway host."""
+        mock_context = MagicMock()
+        mock_plugin = MagicMock()
+
+        mocker.patch("neutron_lib.context.get_admin_context", return_value=mock_context)
+        mocker.patch("neutron_lib.plugins.directory.get_plugin", return_value=mock_plugin)
+
+        mock_plugin.get_agents.return_value = [
+            {"host": "gateway-host-1", "id": "agent-1"}
+        ]
+
+        # Mock port with different binding
+        mock_port = MagicMock()
+        mock_port.id = "port-123"
+        mock_port.bindings = [MagicMock(host="different-host")]
+
+        mocker.patch(
+            "neutron.objects.ports.Port.get_objects", return_value=[mock_port]
+        )
+
+        with pytest.raises(Exception, match="No ports found bound to gateway hosts"):
+            utils.fetch_network_node_trunk_id()
+
+    def test_no_trunk_found(self, mocker):
+        """Test exception when no trunk matches gateway ports."""
+        mock_context = MagicMock()
+        mock_plugin = MagicMock()
+
+        mocker.patch("neutron_lib.context.get_admin_context", return_value=mock_context)
+        mocker.patch("neutron_lib.plugins.directory.get_plugin", return_value=mock_plugin)
+
+        mock_plugin.get_agents.return_value = [
+            {"host": "gateway-host-1", "id": "agent-1"}
+        ]
+
+        mock_port = MagicMock()
+        mock_port.id = "port-123"
+        mock_port.bindings = [MagicMock(host="gateway-host-1")]
+
+        mocker.patch(
+            "neutron.objects.ports.Port.get_objects", return_value=[mock_port]
+        )
+
+        # Mock trunk with different parent port
+        mock_trunk = MagicMock()
+        mock_trunk.id = "trunk-456"
+        mock_trunk.port_id = "different-port"
+
+        mocker.patch(
+            "neutron.objects.trunk.Trunk.get_objects", return_value=[mock_trunk]
+        )
+
+        with pytest.raises(Exception, match="Unable to find network node trunk"):
+            utils.fetch_network_node_trunk_id()
+
+    def test_port_bound_to_resolved_hostname(self, mocker):
+        """Test when port is bound to resolved hostname instead of UUID."""
+        mock_context = MagicMock()
+        mock_plugin = MagicMock()
+
+        mocker.patch("neutron_lib.context.get_admin_context", return_value=mock_context)
+        mocker.patch("neutron_lib.plugins.directory.get_plugin", return_value=mock_plugin)
+
+        gateway_uuid = "7ca98881-bca5-4c82-9369-66eb36292a95"
+        mock_plugin.get_agents.return_value = [{"host": gateway_uuid, "id": "agent-1"}]
+
+        mock_ironic = MagicMock()
+        mock_ironic.baremetal_node_name.return_value = "gateway-host-1"
+        mocker.patch(
+            "neutron_understack.utils.IronicClient", return_value=mock_ironic
+        )
+
+        # Port bound to hostname, not UUID
+        mock_port = MagicMock()
+        mock_port.id = "port-123"
+        mock_port.bindings = [MagicMock(host="gateway-host-1")]
+
+        mocker.patch(
+            "neutron.objects.ports.Port.get_objects", return_value=[mock_port]
+        )
+
+        mock_trunk = MagicMock()
+        mock_trunk.id = "trunk-456"
+        mock_trunk.port_id = "port-123"
+
+        mocker.patch(
+            "neutron.objects.trunk.Trunk.get_objects", return_value=[mock_trunk]
+        )
+
+        result = utils.fetch_network_node_trunk_id()
+
+        assert result == "trunk-456"