diff --git a/tripleo_ansible/ansible_plugins/modules/tripleo_derive_hci_parameters.py b/tripleo_ansible/ansible_plugins/modules/tripleo_derive_hci_parameters.py
index 0a57621e1..896d59f40 100644
--- a/tripleo_ansible/ansible_plugins/modules/tripleo_derive_hci_parameters.py
+++ b/tripleo_ansible/ansible_plugins/modules/tripleo_derive_hci_parameters.py
@@ -259,13 +259,20 @@ def count_osds(tripleo_environment_parameters):
 
 def count_memory(ironic):
     """
-    Counts the memory found in the ironic introspection data as
-    represented by memory_mb. Returns integer of memory in GB.
+    Counts the memory found in the ironic introspection data. If
+    memory_mb is 0, uses ['inventory']['memory']['total'] in bytes.
+    Returns integer of memory in GB.
     """
-    try:
-        memory = ironic['data']['memory_mb'] / float(MB_PER_GB)
-    except KeyError:
-        memory = 0
+    memory = 0
+    if 'data' in ironic:
+        if 'memory_mb' in ironic['data']:
+            if int(ironic['data']['memory_mb']) > 0:
+                memory = int(ironic['data']['memory_mb']) / float(MB_PER_GB)
+            elif 'inventory' in ironic['data']:
+                if 'memory' in ironic['data']['inventory']:
+                    if 'total' in ironic['data']['inventory']['memory']:
+                        memory = int(ironic['data']['inventory']['memory']['total']) \
+                            / float(MB_PER_GB) / float(MB_PER_GB) / float(MB_PER_GB)
     return memory
 
 
diff --git a/tripleo_ansible/tests/modules/test_derive_hci_parameters.py b/tripleo_ansible/tests/modules/test_derive_hci_parameters.py
index 078c70995..256bd4ff0 100644
--- a/tripleo_ansible/tests/modules/test_derive_hci_parameters.py
+++ b/tripleo_ansible/tests/modules/test_derive_hci_parameters.py
@@ -161,3 +161,18 @@ class TestTripleoDeriveHciParameters(tests_base.TestCase):
         der = derive_params.derive(mem_gb=256, vcpus=56, osds=16)
         self.assertFalse(der['failed'])
         self.assertEqual(der['nova_reserved_mem_mb'], 81920)
+
+    def test_count_memory(self):
+        """Test that the count_memory method can the right number
+        regardless of which value ironic might provide.
+        """
+        mock_ironic_memory_mb = {'data':
+                                 {'memory_mb': 262144}}
+        mock_ironic_memory_bytes = {'data':
+                                    {'memory_mb': 0,
+                                     'inventory':
+                                     {'memory':
+                                      {'total': 274877906944}}}}
+        gb_from_mb = derive_params.count_memory(mock_ironic_memory_mb)
+        gb_from_bytes = derive_params.count_memory(mock_ironic_memory_bytes)
+        self.assertEqual(gb_from_mb, gb_from_bytes)