register-nodes: add support for fake_pxe

The fake_pxe driver in Ironic is a driver with a non-op power interface,
so all the power actions needs to be performed manually.

This updates the register-nodes command to support use of the fake_pxe
driver with Ironic.

The flake8 C901 was also added to the tox.ini to be ignored. This error
is raised because we have too much if..elif conditions as part of the
_extract_driver_info() function. It will need some refactoring later,
so ignoring the error for now.

Change-Id: I2de9643ddbdb73c5b49b7572cf476016d4911550

os_cloud_config/nodes.py

@@ -54,6 +54,10 @@ def _extract_driver_info(node):
             driver_info["iboot_relay_id"] = node["pm_relay_id"]
         if "pm_port" in node:
             driver_info["iboot_port"] = node["pm_port"]
+    elif node["pm_type"] == "fake_pxe":
+        # The fake_pxe driver doesn't need any credentials since there's
+        # no power management
+        pass
     else:
         raise ValueError("Unknown pm_type: %s" % node["pm_type"])
     if "pxe" in node["pm_type"]:

tox.ini

@@ -30,7 +30,7 @@ commands = python setup.py test --coverage --coverage-package-name='os_cloud_con
 # E123, E125 skipped as they are invalid PEP-8.
 
 show-source = True
-ignore = E123,E125,H302,H803
+ignore = E123,E125,H302,H803,C901
 builtins = _
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
 max-complexity=14