--- cloudinit/sources/helpers/openstack.py.orig
+++ cloudinit/sources/helpers/openstack.py
@@ -736,7 +736,11 @@ def convert_net_json(network_json=None,
             if not mac:
                 raise ValueError("No mac_address or name entry for %s" % d)
             if mac not in known_macs:
-                raise ValueError("Unable to find a system nic for %s" % d)
+                # Let's give udev a chance to catch up
+                util.udevadm_settle()
+                known_macs = net.get_interfaces_by_mac()
+                if mac not in known_macs:
+                    raise ValueError("Unable to find a system nic for %s" % d)
             d["name"] = known_macs[mac]
 
         for cfg, key, fmt, targets in link_updates:
--- tests/unittests/sources/test_configdrive.py.orig
+++ tests/unittests/sources/test_configdrive.py
@@ -389,6 +389,7 @@ class TestConfigDriveDataSource(CiTestCa
             M_PATH + "util.find_devs_with", "m_find_devs_with", return_value=[]
         )
         self.tmp = self.tmp_dir()
+        self.allowed_subp = True
 
     def test_ec2_metadata(self):
         populate_dir(self.tmp, CFG_DRIVE_FILES_V2)