Ubuntu: Fix networkd config for multiple VLANs without MTU

TypeError: '>' not supported between instances of 'NoneType' and
'NoneType'

Story: 2009013
Task: 42729

Change-Id: I8e25fdc459102ca6e13bd3d38191554ba32c1f48

kayobe/plugins/filter/networkd.py

@@ -626,7 +626,8 @@ def networkd_networks(context, names, inventory_hostname=None):
                             set(bond_member_to_bond))
     for device in implied_vlan_parents:
         vlan_interfaces = interface_to_vlans[device]
-        mtu = max([vlan["mtu"] for vlan in vlan_interfaces])
+        vlan_mtus = [vlan["mtu"] for vlan in vlan_interfaces if vlan["mtu"]]
+        mtu = max(vlan_mtus) if vlan_mtus else None
         net = _vlan_parent_network(device, mtu,
                                    [vlan["device"]
                                     for vlan in vlan_interfaces])

kayobe/tests/unit/plugins/filter/test_networkd.py

@@ -420,6 +420,44 @@ class TestNetworkdNetworks(BaseNetworkdTest):
         }
         self.assertEqual(expected, nets)
 
+    def test_vlan_multiple(self):
+        # Test the case with multiple VLANs on an implied parent without MTUs.
+        # https://storyboard.openstack.org/#!/story/2009013
+        self._update_context({
+            "net5_interface": "eth0.3",
+            "net5_vlan": 3})
+        nets = networkd.networkd_networks(self.context, ["net2", "net5"])
+        expected = {
+            "50-kayobe-eth0": [
+                {
+                    "Match": [
+                        {"Name": "eth0"}
+                    ],
+                },
+                {
+                    "Network": [
+                        {"VLAN": "eth0.2"},
+                        {"VLAN": "eth0.3"},
+                    ]
+                },
+            ],
+            "50-kayobe-eth0.2": [
+                {
+                    "Match": [
+                        {"Name": "eth0.2"}
+                    ]
+                },
+            ],
+            "50-kayobe-eth0.3": [
+                {
+                    "Match": [
+                        {"Name": "eth0.3"}
+                    ]
+                },
+            ]
+        }
+        self.assertEqual(expected, nets)
+
     def test_vlan_with_parent(self):
         nets = networkd.networkd_networks(self.context, ["net1", "net2"])
         expected = {

releasenotes/notes/fix-networkd-vlans-8d5d85da4d2e50ae.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixes an issue with systemd-networkd configuration on Ubuntu with multiple
+    VLAN interfaces. See `story 2009013
+    <https://storyboard.openstack.org/#!/story/2009013>`__ for details.