diff --git a/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/ClusterDefinitionStore.java b/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/ClusterDefinitionStore.java
index a522a85..e3c521e 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/ClusterDefinitionStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/ClusterDefinitionStore.java
@@ -18,6 +18,8 @@
 import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.io.Files;
+
 import java.io.File;
 import java.io.IOException;
 
@@ -43,8 +45,7 @@
      */
     public ClusterDefinition read() throws IOException {
         ObjectMapper mapper = new ObjectMapper();
-        ClusterDefinition definition = mapper.readValue(file, ClusterDefinition.class);
-        return definition;
+        return mapper.readValue(file, ClusterDefinition.class);
     }
 
     /**
@@ -55,7 +56,8 @@
     public void write(ClusterDefinition definition) throws IOException {
         checkNotNull(definition);
         // write back to file
-        final ObjectMapper mapper = new ObjectMapper();
+        Files.createParentDirs(file);
+        ObjectMapper mapper = new ObjectMapper();
         mapper.writeValue(file, definition);
     }
 }
\ No newline at end of file
diff --git a/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/DistributedClusterStore.java b/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/DistributedClusterStore.java
index 0472cff..f5bd773 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/DistributedClusterStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/DistributedClusterStore.java
@@ -17,6 +17,7 @@
 
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
 import com.hazelcast.util.AddressUtil;
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
@@ -37,6 +38,8 @@
 import org.onosproject.cluster.DefaultControllerNode;
 import org.onosproject.cluster.NodeId;
 import org.onosproject.store.AbstractStore;
+import org.onosproject.store.consistent.impl.DatabaseDefinition;
+import org.onosproject.store.consistent.impl.DatabaseDefinitionStore;
 import org.onosproject.store.serializers.KryoNamespaces;
 import org.onosproject.store.serializers.KryoSerializer;
 import org.slf4j.Logger;
@@ -55,11 +58,13 @@
 import java.util.concurrent.TimeUnit;
 import java.util.stream.Collectors;
 
-import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.hazelcast.util.AddressUtil.matchInterface;
 import static java.net.NetworkInterface.getNetworkInterfaces;
 import static java.util.Collections.list;
 import static org.onlab.util.Tools.groupedThreads;
+import static org.onosproject.cluster.DefaultControllerNode.DEFAULT_PORT;
+import static org.onosproject.store.consistent.impl.DatabaseManager.PARTITION_DEFINITION_FILE;
 import static org.slf4j.LoggerFactory.getLogger;
 
 @Component(immediate = true)
@@ -74,17 +79,14 @@
 
     private static final Logger log = getLogger(DistributedClusterStore.class);
 
+    public static final String CLUSTER_DEFINITION_FILE = "../config/cluster.json";
+    public static final String HEARTBEAT_MESSAGE = "onos-cluster-heartbeat";
+
     // TODO: make these configurable.
     private static final int HEARTBEAT_FD_PORT = 2419;
     private static final int HEARTBEAT_INTERVAL_MS = 100;
     private static final int PHI_FAILURE_THRESHOLD = 10;
 
-    private static final String CONFIG_DIR = "../config";
-    private static final String CLUSTER_DEFINITION_FILE = "cluster.json";
-    private static final String HEARTBEAT_MESSAGE = "onos-cluster-heartbeat";
-
-    public static final int DEFAULT_PORT = 9876;
-
     private static final KryoSerializer SERIALIZER = new KryoSerializer() {
         @Override
         protected void setupKryoPool() {
@@ -97,6 +99,8 @@
     };
 
     private static final String INSTANCE_ID_NULL = "Instance ID cannot be null";
+    private static final byte SITE_LOCAL_BYTE = (byte) 0xC0;
+    private static final String ONOS_NIC = "ONOS_NIC";
 
     private ClusterDefinition clusterDefinition;
 
@@ -116,7 +120,7 @@
 
     @Activate
     public void activate() {
-        File clusterDefinitionFile = new File(CONFIG_DIR, CLUSTER_DEFINITION_FILE);
+        File clusterDefinitionFile = new File(CLUSTER_DEFINITION_FILE);
         ClusterDefinitionStore clusterDefinitionStore =
                 new ClusterDefinitionStore(clusterDefinitionFile.getPath());
 
@@ -129,13 +133,12 @@
             seedNodes = ImmutableSet
                     .copyOf(clusterDefinition.getNodes())
                     .stream()
-                    .map(nodeInfo -> new DefaultControllerNode(new NodeId(nodeInfo.getId()),
-                                                               IpAddress.valueOf(nodeInfo.getIp()),
-                                                               nodeInfo.getTcpPort()))
+                    .map(n -> new DefaultControllerNode(new NodeId(n.getId()),
+                                                        IpAddress.valueOf(n.getIp()),
+                                                        n.getTcpPort()))
                     .collect(Collectors.toSet());
         } catch (IOException e) {
-            throw new IllegalStateException(
-                    "Failed to read cluster definition.", e);
+            throw new IllegalStateException("Failed to read cluster definition.", e);
         }
 
         seedNodes.forEach(node -> {
@@ -179,26 +182,30 @@
     }
 
     /**
-     * Returns the site local address if one can be found, loopback otherwise.
+     * Returns the address that matches the IP prefix given in ONOS_NIC
+     * environment variable if one was specified, or the first site local
+     * address if one can be found or the loopback address otherwise.
      *
      * @return site-local address in string form
      */
     public static String getSiteLocalAddress() {
         try {
+            String ipPrefix = System.getenv(ONOS_NIC);
             for (NetworkInterface nif : list(getNetworkInterfaces())) {
                 for (InetAddress address : list(nif.getInetAddresses())) {
-                    if (address.getAddress()[0] == (byte) 0xC0) {
-                        return address.toString().substring(1);
+                    IpAddress ip = IpAddress.valueOf(address);
+                    if (ipPrefix == null && address.isSiteLocalAddress() ||
+                            ipPrefix != null && matchInterface(ip.toString(), ipPrefix)) {
+                        return ip.toString();
                     }
                 }
             }
-            return InetAddress.getLoopbackAddress().toString().substring(1);
 
         } catch (SocketException e) {
             log.error("Unable to get network interfaces", e);
         }
 
-        return null;
+        return IpAddress.valueOf(InetAddress.getLoopbackAddress()).toString();
     }
 
     @Deactivate
@@ -255,9 +262,6 @@
 
     @Override
     public ControllerNode addNode(NodeId nodeId, IpAddress ip, int tcpPort) {
-        checkNotNull(nodeId, INSTANCE_ID_NULL);
-        checkNotNull(ip, "IP address must not be null");
-        checkArgument(tcpPort > 5000, "Tcp port must be greater than 5000");
         ControllerNode node = new DefaultControllerNode(nodeId, ip, tcpPort);
         allNodes.put(node.id(), node);
         updateState(nodeId, State.INACTIVE);
@@ -275,6 +279,24 @@
         }
     }
 
+    @Override
+    public void formCluster(Set<ControllerNode> nodes, String ipPrefix) {
+        try {
+            Set<NodeInfo> infos = Sets.newHashSet();
+            nodes.forEach(n -> infos.add(NodeInfo.from(n.id().toString(),
+                                                       n.ip().toString(),
+                                                       n.tcpPort())));
+
+            ClusterDefinition cdef = ClusterDefinition.from(infos, ipPrefix);
+            new ClusterDefinitionStore(CLUSTER_DEFINITION_FILE).write(cdef);
+
+            DatabaseDefinition ddef = DatabaseDefinition.from(infos);
+            new DatabaseDefinitionStore(PARTITION_DEFINITION_FILE).write(ddef);
+        } catch (IOException e) {
+            log.error("Unable to form cluster", e);
+        }
+    }
+
     private void updateState(NodeId nodeId, State newState) {
         nodeStates.put(nodeId, newState);
         nodeStateLastUpdatedTimes.put(nodeId, DateTime.now());
@@ -387,4 +409,5 @@
     public DateTime getLastUpdated(NodeId nodeId) {
         return nodeStateLastUpdatedTimes.get(nodeId);
     }
+
 }
diff --git a/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/HazelcastClusterStore.java b/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/HazelcastClusterStore.java
index 55d877d..827fec2 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/HazelcastClusterStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/cluster/impl/HazelcastClusterStore.java
@@ -24,12 +24,12 @@
 import com.hazelcast.core.MemberAttributeEvent;
 import com.hazelcast.core.MembershipEvent;
 import com.hazelcast.core.MembershipListener;
-
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Service;
 import org.joda.time.DateTime;
+import org.onlab.packet.IpAddress;
 import org.onosproject.cluster.ClusterEvent;
 import org.onosproject.cluster.ClusterStore;
 import org.onosproject.cluster.ClusterStoreDelegate;
@@ -39,7 +39,6 @@
 import org.onosproject.store.hz.AbsentInvalidatingLoadingCache;
 import org.onosproject.store.hz.AbstractHazelcastStore;
 import org.onosproject.store.hz.OptionalCacheLoader;
-import org.onlab.packet.IpAddress;
 
 import java.util.Map;
 import java.util.Set;
@@ -131,6 +130,11 @@
     }
 
     @Override
+    public void formCluster(Set<ControllerNode> nodes, String ipPrefix) {
+        throw new UnsupportedOperationException("formCluster not implemented");
+    }
+
+    @Override
     public ControllerNode addNode(NodeId nodeId, IpAddress ip, int tcpPort) {
         return addNode(new DefaultControllerNode(nodeId, ip, tcpPort));
     }