Allow placement endpoint interface to be set

This patch exposes the "interface" option for ks_filter to allow
the placement API to be connected on a specific endpoint interface.

The previous was to force "public", which is default for keystoneauth.
The default for the placement service mirrors this value.

Change-Id: Ic996e596f8473c0b8626e8d0e92e1bf58044b4f8

nova/conf/placement.py

@@ -28,6 +28,13 @@ Possible values:
 
 * Any string representing region name
 """),
+    cfg.StrOpt('os_interface',
+               default="public",
+               choices=["public", "admin", "internal"],
+               help="""
+Endpoint interface for this node. This is used when picking the URL in the
+service catalog.
+""")
 ]
 
 

releasenotes/notes/placement-api-endpoint-interface-set-29af8b9400ce7775.yaml

@@ -0,0 +1,7 @@
+---
+features:
+  - The placement API can be set to connect to a specific
+    keystone endpoint interface using the ``os_interface``
+    option in the ``[placement]`` section inside ``nova.conf``.
+    This value is not required and will default to ``public``.
+    Other acceptable options are  ``admin`` or ``internal``.