allows api servers to have a list of regions, allowing multi-cluster support if you have a shared image store and user database.

nova/endpoint/cloud.py

@@ -162,9 +162,18 @@ class CloudController(object):
 
     @rbac.allow('all')
     def describe_regions(self, context, region_name=None, **kwargs):
-        # TODO(vish): region_name is an array.  Support filtering
-        return {'regionInfo': [{'regionName': 'nova',
-                                'regionUrl': FLAGS.ec2_url}]}
+        if FLAGS.region_list:
+            regions = []
+            for region in FLAGS.region_list:
+                name, _sep, url = region.partition('=')
+                regions.append({'regionName': name,
+                                'regionEndpoint': url})
+        else:
+            regions = [{'regionName': 'nova',
+                        'regionEndpoint': FLAGS.ec2_url}]
+        if region_name:
+            regions = [r for r in regions if r['regionName'] in region_name]
+        return {'regionInfo': regions }
 
     @rbac.allow('all')
     def describe_snapshots(self,

nova/flags.py

@@ -167,6 +167,9 @@ def DECLARE(name, module_string, flag_values=FLAGS):
 # Define any app-specific flags in their own files, docs at:
 # http://code.google.com/p/python-gflags/source/browse/trunk/gflags.py#39
 
+DEFINE_list('region_list',
+            [],
+            'list of region=url pairs separated by commas')
 DEFINE_string('connection_type', 'libvirt', 'libvirt, xenapi or fake')
 DEFINE_integer('s3_port', 3333, 's3 port')
 DEFINE_string('s3_host', '127.0.0.1', 's3 host')