diff --git a/doc/source/usage.rst b/doc/source/usage.rst
index 5628ba6..4cc7f2c 100644
--- a/doc/source/usage.rst
+++ b/doc/source/usage.rst
@@ -79,6 +79,10 @@ Where ``/tmp/one-node`` contains::
       }
     ]
 
+ .. note::
+
+    The memory, disk, arch, and cpu fields are optional and can be omitted.
+
 ----------------------------------------------------------
 Generating keys and certificates for use with Keystone PKI
 ----------------------------------------------------------
diff --git a/os_cloud_config/nodes.py b/os_cloud_config/nodes.py
index 8abf35c..e5ac5f9 100644
--- a/os_cloud_config/nodes.py
+++ b/os_cloud_config/nodes.py
@@ -162,10 +162,13 @@ def _extract_driver_info(node):
 
 
 def register_ironic_node(service_host, node, client=None, blocking=True):
-    properties = {"cpus": six.text_type(node["cpu"]),
-                  "memory_mb": six.text_type(node["memory"]),
-                  "local_gb": six.text_type(node["disk"]),
-                  "cpu_arch": node["arch"]}
+    mapping = {'cpus': 'cpu',
+               'memory_mb': 'memory',
+               'local_gb': 'disk',
+               'cpu_arch': 'arch'}
+    properties = {k: six.text_type(node.get(v))
+                  for k, v in mapping.items()
+                  if node.get(v) is not None}
     driver_info = _extract_driver_info(node)
 
     if 'capabilities' in node:
diff --git a/os_cloud_config/tests/test_nodes.py b/os_cloud_config/tests/test_nodes.py
index 616f54d..692bca9 100644
--- a/os_cloud_config/tests/test_nodes.py
+++ b/os_cloud_config/tests/test_nodes.py
@@ -226,6 +226,36 @@ class NodesTest(base.TestCase):
         node["pm_type"] = "unknown_type"
         self.assertRaises(ValueError, nodes._extract_driver_info, node)
 
+    def test_register_all_nodes_ironic_no_hw_stats(self):
+        node_list = [self._get_node()]
+
+        # Remove the hardware stats from the node dictionary
+        node_list[0].pop("cpu")
+        node_list[0].pop("memory")
+        node_list[0].pop("disk")
+        node_list[0].pop("arch")
+
+        # Node properties should be created with empty string values for the
+        # hardware statistics
+        node_properties = {"capabilities": "num_nics:6"}
+
+        ironic = mock.MagicMock()
+        nodes.register_all_nodes('servicehost', node_list, client=ironic)
+        pxe_node_driver_info = {"ssh_address": "foo.bar",
+                                "ssh_username": "test",
+                                "ssh_key_contents": "random",
+                                "ssh_virt_type": "virsh"}
+        pxe_node = mock.call(driver="pxe_ssh",
+                             name='node1',
+                             driver_info=pxe_node_driver_info,
+                             properties=node_properties)
+        port_call = mock.call(node_uuid=ironic.node.create.return_value.uuid,
+                              address='aaa')
+        power_off_call = mock.call(ironic.node.create.return_value.uuid, 'off')
+        ironic.node.create.assert_has_calls([pxe_node, mock.ANY])
+        ironic.port.create.assert_has_calls([port_call])
+        ironic.node.set_power_state.assert_has_calls([power_off_call])
+
     def test_register_all_nodes_ironic(self):
         node_list = [self._get_node()]
         node_properties = {"cpus": "1",