Use sysmetadata to get instance_name in API

Change-Id: If2ca9ff307f0d9b977d76f6ba8f34fb828c893cd

nova/api/openstack/compute/contrib/extended_server_attributes.py

@@ -14,15 +14,26 @@
 
 """The Extended Server Attributes API extension."""
 
+from oslo.config import cfg
+
 from nova.api.openstack import extensions
 from nova.api.openstack import wsgi
 from nova.api.openstack import xmlutil
+from nova import utils
+
+CONF = cfg.CONF
 
 authorize = extensions.soft_extension_authorizer('compute',
                                                  'extended_server_attributes')
 
 
 class ExtendedServerAttributesController(wsgi.Controller):
+    def _get_hypervisor_instance_name(self, context, instance):
+        if not CONF.cells.enable:
+            return instance['name']
+        sys_metadata = utils.instance_sys_meta(instance)
+        return sys_metadata.get('instance_name', '')
+
     def _extend_server(self, context, server, instance):
         key = "%s:hypervisor_hostname" % Extended_server_attributes.alias
         server[key] = instance['node']
@@ -31,9 +42,11 @@ def _extend_server(self, context, server, instance):
             if attr == 'name':
                 key = "%s:instance_%s" % (Extended_server_attributes.alias,
                                           attr)
+                server[key] = self._get_hypervisor_instance_name(context,
+                                                                 instance)
             else:
                 key = "%s:%s" % (Extended_server_attributes.alias, attr)
-            server[key] = instance[attr]
+                server[key] = instance[attr]
 
     @wsgi.extends
     def show(self, req, resp_obj, id):