@Override
                 public String isConditionMet() {
                     if (currentState == null) {
                         return "No cluster state defined yet";
                     }
                     NodeState distState = currentState.getNodeState(new Node(NodeType.DISTRIBUTOR, 0));
                     if (distState.getState() != State.DOWN) {
                         return "Distributor not detected down yet: " + currentState.toString();
                     }
                     NodeState storState = currentState.getNodeState(new Node(NodeType.STORAGE, 9));
                     if (!storState.getState().oneOf("md")) {
                         return "Storage node not detected down yet: " + currentState.toString();
                     }
                     return null;
                 }
Note: RpcServer is only used in unit tests

@author humbe
clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/RpcServerTest.java