diff --git a/core/api/src/main/java/org/onlab/onos/cluster/DefaultControllerNode.java b/core/api/src/main/java/org/onlab/onos/cluster/DefaultControllerNode.java
index 9735fdb..86ea14c 100644
--- a/core/api/src/main/java/org/onlab/onos/cluster/DefaultControllerNode.java
+++ b/core/api/src/main/java/org/onlab/onos/cluster/DefaultControllerNode.java
@@ -14,6 +14,12 @@
     private final NodeId id;
     private final IpPrefix ip;
 
+    // For serialization
+    private DefaultControllerNode() {
+        this.id = null;
+        this.ip = null;
+    }
+
     /**
      * Creates a new instance with the specified id and IP address.
      *