diff --git a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/clusterconfig/ClusterConfig.java b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/clusterconfig/ClusterConfig.java
index 49309ec..db18e53 100644
--- a/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/clusterconfig/ClusterConfig.java
+++ b/pregelix/pregelix-core/src/main/java/edu/uci/ics/pregelix/core/jobgen/clusterconfig/ClusterConfig.java
@@ -26,6 +26,7 @@
 import java.util.Map;
 import java.util.Properties;
 import java.util.Random;
+import java.util.TreeMap;
 
 import org.apache.hadoop.mapreduce.InputSplit;
 
@@ -197,7 +198,8 @@
     public static void loadClusterConfig(String ipAddress, int port) throws HyracksException {
         try {
             IHyracksClientConnection hcc = new HyracksConnection(ipAddress, port);
-            Map<String, NodeControllerInfo> ncNameToNcInfos = hcc.getNodeControllerInfos();
+            Map<String, NodeControllerInfo> ncNameToNcInfos = new TreeMap<String, NodeControllerInfo>();
+            ncNameToNcInfos.putAll(hcc.getNodeControllerInfos());
             NCs = new String[ncNameToNcInfos.size()];
             ipToNcMapping = new HashMap<String, List<String>>();
             int i = 0;