diff --git a/unit_tests/utilities/test_zaza_utilities_generic.py b/unit_tests/utilities/test_zaza_utilities_generic.py
index 0f3ff9c..f1a648f 100644
--- a/unit_tests/utilities/test_zaza_utilities_generic.py
+++ b/unit_tests/utilities/test_zaza_utilities_generic.py
@@ -429,6 +429,20 @@ class TestGenericUtils(ut_utils.BaseTestCase):
         actual = generic_utils.get_unit_hostnames(_units)
 
         self.assertEqual(actual, expected)
+        expected_run_calls = [
+            mock.call('testunit/1', 'hostname'),
+            mock.call('testunit/2', 'hostname')]
+        self._run.assert_has_calls(expected_run_calls)
+
+        self._run.reset_mock()
+        self._run.side_effect = [{"Stdout": _hostname1},
+                                 {"Stdout": _hostname2}]
+        expected_run_calls = [
+            mock.call('testunit/1', 'hostname -f'),
+            mock.call('testunit/2', 'hostname -f')]
+
+        actual = generic_utils.get_unit_hostnames(_units, fqdn=True)
+        self._run.assert_has_calls(expected_run_calls)
 
     def test_port_knock_units(self):
         self.patch(
diff --git a/zaza/openstack/utilities/generic.py b/zaza/openstack/utilities/generic.py
index e342369..9143297 100644
--- a/zaza/openstack/utilities/generic.py
+++ b/zaza/openstack/utilities/generic.py
@@ -113,11 +113,14 @@ def get_network_config(net_topology, ignore_env_vars=False,
     return net_info
 
 
-def get_unit_hostnames(units):
+def get_unit_hostnames(units, fqdn=False):
     """Return a dict of juju unit names to hostnames."""
     host_names = {}
     for unit in units:
-        output = model.run_on_unit(unit.entity_id, 'hostname')
+        cmd = 'hostname'
+        if fqdn:
+            cmd = cmd + ' -f'
+        output = model.run_on_unit(unit.entity_id, cmd)
         hostname = output['Stdout'].strip()
         host_names[unit.entity_id] = hostname
     return host_names