Ubuntu systemd-networkd: VLAN ifname heuristics

Add a regular expression match to verify that VLAN
interfaces are named like VLAN interfaces, enabling
non-VLAN interfaces to exist on a network where the
VLAN ID is defined.

Co-Authored-By: Mark Goddard <mark@stackhpc.com>
Story: 2009270
Task: 43511
Change-Id: If09c4840bbe51168a8b94be0db85e6610c21aa82

kayobe/plugins/filter/networkd.py

@@ -488,8 +488,9 @@ def _add_to_result(result, prefix, device, config):
     # This should not happen.
     if key in result:
         raise errors.AnsibleFilterError(
-            "Programming error: duplicate interface configuration for %s"
-            % device)
+            "Programming error: duplicate interface configuration for %s: "
+            "have %s"
+            % (device, result))
     result[key] = config
 
 
@@ -511,7 +512,8 @@ def networkd_netdevs(context, names, inventory_hostname=None):
     result = {}
 
     # VLANs.
-    for name in networks.net_select_vlans(context, names, inventory_hostname):
+    for name in networks.net_select_vlan_interfaces(context, names,
+                                                    inventory_hostname):
         device = networks.get_and_validate_interface(context, name,
                                                      inventory_hostname)
         netdev = _vlan_netdev(context, name, inventory_hostname)

kayobe/plugins/filter/networks.py

@@ -535,6 +535,14 @@ def net_is_vlan(context, name, inventory_hostname=None):
     return net_vlan(context, name) is not None
 
 
+@jinja2.contextfilter
+def net_is_vlan_interface(context, name, inventory_hostname=None):
+    device = get_and_validate_interface(context, name, inventory_hostname)
+    # Use a heuristic to match conventional VLAN names, ending with a
+    # period and a numerical extension to an interface name
+    return re.match(r"^[a-zA-Z0-9_\-]+\.[1-9][\d]{0,3}$", device)
+
+
 @jinja2.contextfilter
 def net_select_ethers(context, names, inventory_hostname=None):
     return [name for name in names
@@ -559,6 +567,12 @@ def net_select_vlans(context, names, inventory_hostname=None):
             if net_is_vlan(context, name, inventory_hostname)]
 
 
+@jinja2.contextfilter
+def net_select_vlan_interfaces(context, names, inventory_hostname=None):
+    return [name for name in names
+            if net_is_vlan_interface(context, name, inventory_hostname)]
+
+
 @jinja2.contextfilter
 def net_reject_vlans(context, names, inventory_hostname=None):
     return [name for name in names

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

@@ -74,6 +74,19 @@ class TestNetworkdNetDevs(BaseNetworkdTest):
         devs = networkd.networkd_netdevs(self.context, [])
         self.assertEqual({}, devs)
 
+    def test_eth(self):
+        devs = networkd.networkd_netdevs(self.context, ["net1"])
+        expected = {}
+        self.assertEqual(expected, devs)
+
+    def test_eth_untagged_vlan(self):
+        # An untagged interface on a network with a VLAN defined should not
+        # create a VLAN subinterface.
+        self._update_context({"net1_vlan": 42})
+        devs = networkd.networkd_netdevs(self.context, ["net1"])
+        expected = {}
+        self.assertEqual(expected, devs)
+
     def test_vlan(self):
         devs = networkd.networkd_netdevs(self.context, ["net2"])
         expected = {
@@ -154,6 +167,23 @@ class TestNetworkdNetDevs(BaseNetworkdTest):
         self.assertRaises(errors.AnsibleFilterError,
                           networkd.networkd_netdevs, self.context, ["net3"])
 
+    def test_bridge_untagged_vlan(self):
+        # A bridge on a network with a VLAN defined should not create a VLAN
+        # subinterface.
+        self._update_context({"net3_vlan": 42})
+        devs = networkd.networkd_netdevs(self.context, ["net3"])
+        expected = {
+            "50-kayobe-br0": [
+                {
+                    "NetDev": [
+                        {"Name": "br0"},
+                        {"Kind": "bridge"},
+                    ]
+                },
+            ]
+        }
+        self.assertEqual(expected, devs)
+
     def test_bond(self):
         devs = networkd.networkd_netdevs(self.context, ["net4"])
         expected = {
@@ -207,6 +237,23 @@ class TestNetworkdNetDevs(BaseNetworkdTest):
         self.assertRaises(errors.AnsibleFilterError,
                           networkd.networkd_netdevs, self.context, ["net4"])
 
+    def test_bond_untagged_vlan(self):
+        # A bridge on a network with a VLAN defined should not create a VLAN
+        # subinterface.
+        self._update_context({"net4_vlan": 42})
+        devs = networkd.networkd_netdevs(self.context, ["net4"])
+        expected = {
+            "50-kayobe-bond0": [
+                {
+                    "NetDev": [
+                        {"Name": "bond0"},
+                        {"Kind": "bond"},
+                    ]
+                },
+            ]
+        }
+        self.assertEqual(expected, devs)
+
     def test_veth(self):
         self._update_context({"external_net_names": ["net3"]})
         devs = networkd.networkd_netdevs(self.context, ["net3"])

releasenotes/notes/fix-networkd-vlan-netdev-1668f8e0f9647ef8.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fixes an issue with ``systemd-networkd`` configuration for VLAN interfaces
+    when the interface is untagged.