improve OS preparation, change config structure
diff --git a/wally/discover/discover.py b/wally/discover/discover.py
index 73407c0..3cab884 100644
--- a/wally/discover/discover.py
+++ b/wally/discover/discover.py
@@ -57,7 +57,10 @@
                                                           cluster_info)
             nodes_to_run.extend(os_nodes)
 
-        elif cluster == "fuel":
+        elif cluster == "fuel" or cluster == "fuel_openrc_only":
+            if cluster == "fuel_openrc_only":
+                discover_nodes = False
+
             res = fuel.discover_fuel_nodes(clusters_info['fuel'],
                                            var_dir,
                                            discover_nodes)