Remove requirement of specifying hardware stats

With introspection in place, there is no longer a hard requirement of
knowing the hardware statistics (cpu, memory, disk, arch) of nodes when
initially registering them with Ironic.

The requirement was never on the Ironic side, it was only enforced here
in os-cloud-config. Previously, to get around the requirement, one could
just specify an empty string value for these statistics in the nodes
json file.

This change makes it such that these keys do not even have to exist in
the json anymore.

Add a unit test as well that verifies this change.

Change-Id: Idcc5a9a4ac043c88fe0102626eefb327476819fd

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
 ----------------------------------------------------------

os_cloud_config/nodes.py

@@ -80,10 +80,13 @@ 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:

os_cloud_config/tests/test_nodes.py

@@ -152,6 +152,36 @@ 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",