static Map<String,Map<String,Set<String>>> keepNewServicesOnly(Map<String,Map<String,Set<String>>> recommendedLayout, Map<String,Map<String,Set<String>>> newServices) {
    HashMap<String, java.util.Map<String, Set<String>>> newServiceRecommendations = new HashMap<>(recommendedLayout);
    newServiceRecommendations.keySet().retainAll(newServices.keySet());
    return newServiceRecommendations;
  }
Reuse information from layout recommendation if it happened
ambari-server/src/main/java/org/apache/ambari/server/topology/addservice/StackAdvisorAdapter.java