Small code improvements.

* avoid None iteration in configs util
* display instances in cluster details
* display more info while provisioning cluster

Change-Id: I33026468911a3f93695468cde8d67db02485a77a

savanna/db/models.py

@@ -135,6 +135,12 @@ class NodeGroup(mb.SavannaBase, mb.IdMixin, mb.ExtraMixin):
 
         return self._all_configs
 
+    def to_dict(self):
+        d = super(NodeGroup, self).to_dict()
+        d['instances'] = [i.dict for i in self.instances]
+
+        return d
+
 
 class Instance(mb.SavannaBase, mb.ExtraMixin):
     """An OpenStack instance created for the cluster."""

savanna/service/instances.py

@@ -131,7 +131,8 @@ def _check_if_up(instance):
         if exit_code:
             return False
     except Exception as ex:
-        LOG.debug("Can't login to node %s reason %s", server.name, ex)
+        LOG.debug("Can't login to node %s (%s), reason %s",
+                  server.name, instance.management_ip, ex)
         return False
 
     instance._is_up = True

savanna/utils/configs.py

@@ -23,9 +23,10 @@ def merge_configs(*configs):
     """
     result = {}
     for config in configs:
-        for a_target in config:
-            if a_target not in result or not result[a_target]:
-                result[a_target] = {}
-            result[a_target].update(config[a_target])
+        if config:
+            for a_target in config:
+                if a_target not in result or not result[a_target]:
+                    result[a_target] = {}
+                result[a_target].update(config[a_target])
 
     return result