diff --git a/src/main/java/net/onrc/onos/datastore/hazelcast/HZClient.java b/src/main/java/net/onrc/onos/datastore/hazelcast/HZClient.java
new file mode 100644
index 0000000..2c2b3a4
--- /dev/null
+++ b/src/main/java/net/onrc/onos/datastore/hazelcast/HZClient.java
@@ -0,0 +1,345 @@
+package net.onrc.onos.datastore.hazelcast;
+
+import java.io.FileNotFoundException;
+import java.util.Collection;
+import java.util.List;
+
+import net.onrc.onos.datastore.IKVClient;
+import net.onrc.onos.datastore.IKVTable;
+import net.onrc.onos.datastore.IKVTable.IKVEntry;
+import net.onrc.onos.datastore.IKVTableID;
+import net.onrc.onos.datastore.IMultiEntryOperation;
+import net.onrc.onos.datastore.IMultiEntryOperation.OPERATION;
+import net.onrc.onos.datastore.IMultiEntryOperation.STATUS;
+import net.onrc.onos.datastore.ObjectDoesntExistException;
+import net.onrc.onos.datastore.ObjectExistsException;
+import net.onrc.onos.datastore.WrongVersionException;
+import net.onrc.onos.datastore.hazelcast.HZTable.VersionedValue;
+import net.onrc.onos.datastore.internal.IModifiableMultiEntryOperation;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.hazelcast.client.HazelcastClient;
+import com.hazelcast.client.config.ClientConfig;
+import com.hazelcast.config.Config;
+import com.hazelcast.config.FileSystemXmlConfig;
+import com.hazelcast.config.MapConfig;
+import com.hazelcast.config.SerializationConfig;
+import com.hazelcast.core.Hazelcast;
+import com.hazelcast.core.HazelcastInstance;
+import com.hazelcast.core.IMap;
+
+public class HZClient implements IKVClient {
+    private static final Logger log = LoggerFactory.getLogger(HZClient.class);
+
+    static final long VERSION_NONEXISTENT = 0L;
+
+    private static final String MAP_PREFIX = "datastore://";
+
+    // make this path configurable
+    private static final String BASE_CONFIG_FILENAME = System.getProperty("net.onrc.onos.datastore.hazelcast.baseConfig", "conf/hazelcast.xml");
+    private static boolean useClientMode = Boolean.parseBoolean(System.getProperty("net.onrc.onos.datastore.hazelcast.clientMode", "true"));
+
+    // Note: xml configuration will overwrite this value if present
+    private static int backupCount = Integer.valueOf(System.getProperty("net.onrc.onos.datastore.hazelcast.backupCount", "3"));
+
+    private final HazelcastInstance hazelcastInstance;
+
+    private static final HZClient THE_INSTANCE = new HZClient();
+
+    public static HZClient getClient() {
+	return THE_INSTANCE;
+    }
+
+    private HZClient() {
+	hazelcastInstance = getHZinstance(BASE_CONFIG_FILENAME);
+    }
+
+    private static HazelcastInstance getHZinstance(final String hazelcastConfigFileName) {
+	Config baseHzConfig = null;
+	try {
+	    baseHzConfig = new FileSystemXmlConfig(hazelcastConfigFileName);
+	} catch (FileNotFoundException e) {
+	    log.error("Error opening Hazelcast XML configuration. File not found: " + hazelcastConfigFileName, e);
+	    throw new Error("Cannot find Hazelcast configuration: " + hazelcastConfigFileName , e);
+	}
+
+	// use xml config if present, if not use System.property
+	MapConfig mapConfig = baseHzConfig.getMapConfigs().get(MAP_PREFIX + "*");
+	if (mapConfig != null) {
+	    backupCount = mapConfig.getBackupCount();
+	}
+
+	HazelcastInstance instance = null;
+	if (useClientMode) {
+	    log.info("Configuring Hazelcast datastore as Client mode");
+	    ClientConfig clientConfig = new ClientConfig();
+	    final int port = baseHzConfig.getNetworkConfig().getPort();
+
+	    String server = System.getProperty("net.onrc.onos.datastore.hazelcast.client.server", "localhost");
+	    clientConfig.addAddress(server + ":" + port);
+
+	    // copy group config from base Hazelcast configuration
+	    clientConfig.getGroupConfig().setName(baseHzConfig.getGroupConfig().getName());
+	    clientConfig.getGroupConfig().setPassword(baseHzConfig.getGroupConfig().getPassword());
+
+	    // TODO We probably need to figure out what else need to be
+	    // derived from baseConfig
+
+	    registerSerializer(clientConfig.getSerializationConfig());
+
+	    log.info("Starting Hazelcast datastore client for [{}]", clientConfig.getAddressList());
+
+	    try {
+		instance = HazelcastClient.newHazelcastClient(clientConfig);
+		if (!instance.getCluster().getMembers().isEmpty()) {
+		    log.debug("Members in cluster: " + instance.getCluster().getMembers());
+		    return instance;
+		}
+		log.info("Failed to find cluster member, falling back to Instance mode");
+	    } catch (IllegalStateException e) {
+		log.info("Failed to initialize HazelcastClient, falling back to Instance mode");
+	    }
+	    useClientMode = false;
+	    instance = null;
+	}
+	log.info("Configuring Hazelcast datastore as Instance mode");
+
+	// To run 2 Hazelcast instance in 1 JVM,
+	// we probably need to something like below
+	//int port = hazelcastConfig.getNetworkConfig().getPort();
+	//hazelcastConfig.getNetworkConfig().setPort(port+1);
+
+	registerSerializer(baseHzConfig.getSerializationConfig());
+
+	return Hazelcast.newHazelcastInstance(baseHzConfig);
+    }
+
+    /**
+     * Register serializer for VersionedValue class used to imitate value version.
+     * @param config
+     */
+    private static void registerSerializer(final SerializationConfig config) {
+	config.addDataSerializableFactoryClass(
+		    VersionedValueSerializableFactory.FACTORY_ID,
+		    VersionedValueSerializableFactory.class);
+    }
+
+    @Override
+    public IKVTable getTable(final String tableName) {
+	IMap<byte[], VersionedValue> map = hazelcastInstance.getMap(MAP_PREFIX + tableName);
+
+	if (!useClientMode) {
+	    // config only available in Instance Mode
+	    // Client Mode must rely on hazelcast.xml to be properly configured.
+	    MapConfig config = hazelcastInstance.getConfig().getMapConfig(MAP_PREFIX + tableName);
+	    // config for this map to be strong consistent
+	    if (config.isReadBackupData()) {
+		config.setReadBackupData(false);
+	    }
+	    if (config.isNearCacheEnabled()) {
+		config.getNearCacheConfig().setMaxSize(0);
+	    }
+
+	    if (config.getBackupCount() != backupCount) {
+		config.setAsyncBackupCount(0);
+		config.setBackupCount(backupCount);
+	    }
+	}
+
+	return new HZTable(tableName, map);
+    }
+
+    @Override
+    public void dropTable(final IKVTable table) {
+	((HZTable) table).getBackendMap().clear();
+    }
+
+    @Override
+    public long create(final IKVTableID tableId, final byte[] key, final byte[] value)
+            throws ObjectExistsException {
+	IKVTable table = (IKVTable) tableId;
+	return table.create(key, value);
+    }
+
+    @Override
+    public long forceCreate(final IKVTableID tableId, final byte[] key, final byte[] value) {
+	IKVTable table = (IKVTable) tableId;
+	return table.forceCreate(key, value);
+    }
+
+    @Override
+    public IKVEntry read(final IKVTableID tableId, final byte[] key)
+            throws ObjectDoesntExistException {
+	IKVTable table = (IKVTable) tableId;
+	return table.read(key);
+    }
+
+    @Override
+    public long update(final IKVTableID tableId, final byte[] key, final byte[] value,
+            final long version) throws ObjectDoesntExistException,
+            WrongVersionException {
+	IKVTable table = (IKVTable) tableId;
+	return table.update(key, value, version);
+    }
+
+    @Override
+    public long update(final IKVTableID tableId, final byte[] key, final byte[] value)
+            throws ObjectDoesntExistException {
+	IKVTable table = (IKVTable) tableId;
+	return table.update(key, value);
+    }
+
+    @Override
+    public long delete(final IKVTableID tableId, final byte[] key, final long version)
+            throws ObjectDoesntExistException, WrongVersionException {
+	IKVTable table = (IKVTable) tableId;
+	return table.delete(key, version);
+    }
+
+    @Override
+    public long forceDelete(final IKVTableID tableId, final byte[] key) {
+	IKVTable table = (IKVTable) tableId;
+	return table.forceDelete(key);
+    }
+
+    @Override
+    public Iterable<IKVEntry> getAllEntries(final IKVTableID tableId) {
+	IKVTable table = (IKVTable) tableId;
+	return table.getAllEntries();
+    }
+
+    @Override
+    public IMultiEntryOperation createOp(final IKVTableID tableId, final byte[] key,
+            final byte[] value) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, value, HZClient.VERSION_NONEXISTENT, OPERATION.CREATE);
+    }
+
+    @Override
+    public IMultiEntryOperation forceCreateOp(final IKVTableID tableId, final byte[] key,
+            final byte[] value) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, value, HZClient.VERSION_NONEXISTENT, OPERATION.FORCE_CREATE);
+    }
+
+    @Override
+    public IMultiEntryOperation readOp(final IKVTableID tableId, final byte[] key) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, OPERATION.READ);
+    }
+
+    @Override
+    public IMultiEntryOperation updateOp(final IKVTableID tableId, final byte[] key,
+            final byte[] value, final long version) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, value, version, OPERATION.UPDATE);
+    }
+
+    @Override
+    public IMultiEntryOperation deleteOp(final IKVTableID tableId, final byte[] key,
+            final byte[] value, final long version) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, value, version, OPERATION.DELETE);
+    }
+
+    @Override
+    public IMultiEntryOperation forceDeleteOp(final IKVTableID tableId, final byte[] key) {
+	return new HZMultiEntryOperation((HZTable) tableId, key, OPERATION.FORCE_DELETE);
+    }
+
+    @Override
+    public boolean multiDelete(final Collection<IMultiEntryOperation> ops) {
+	boolean failExists = false;
+	for (IMultiEntryOperation op : ops) {
+	    HZMultiEntryOperation mop = (HZMultiEntryOperation) op;
+	    switch (mop.getOperation()) {
+	    case DELETE:
+		try {
+		    final long version = delete(mop.getTableId(), mop.getKey(), mop.getVersion());
+		    mop.setVersion(version);
+		    mop.setStatus(STATUS.SUCCESS);
+		} catch (ObjectDoesntExistException | WrongVersionException e) {
+		    log.error(mop + " failed.", e);
+		    mop.setStatus(STATUS.FAILED);
+                    failExists = true;
+		}
+		break;
+	    case FORCE_DELETE:
+		final long version = forceDelete(mop.getTableId(), mop.getKey());
+		mop.setVersion(version);
+		mop.setStatus(STATUS.SUCCESS);
+		break;
+	    default:
+		throw new UnsupportedOperationException(mop.toString());
+	    }
+	}
+	return failExists;
+    }
+
+    @Override
+    public boolean multiWrite(final List<IMultiEntryOperation> ops) {
+	// there may be room to batch to improve performance
+	boolean failExists = false;
+	for (IMultiEntryOperation op : ops) {
+	    IModifiableMultiEntryOperation mop = (IModifiableMultiEntryOperation) op;
+	    switch (mop.getOperation()) {
+	    case CREATE:
+		try {
+		    long version = create(mop.getTableId(), mop.getKey(), mop.getValue());
+		    mop.setVersion(version);
+		    mop.setStatus(STATUS.SUCCESS);
+		} catch (ObjectExistsException e) {
+		    log.error(mop + " failed.", e);
+		    mop.setStatus(STATUS.FAILED);
+		    failExists = true;
+		}
+		break;
+	    case FORCE_CREATE:
+	    {
+		final long version = forceCreate(mop.getTableId(), mop.getKey(), mop.getValue());
+		mop.setVersion(version);
+		mop.setStatus(STATUS.SUCCESS);
+		break;
+	    }
+	    case UPDATE:
+		try {
+		    long version = update(mop.getTableId(), mop.getKey(), mop.getValue(), mop.getVersion());
+		    mop.setVersion(version);
+		    mop.setStatus(STATUS.SUCCESS);
+		} catch (ObjectDoesntExistException | WrongVersionException e) {
+		    log.error(mop + " failed.", e);
+		    mop.setStatus(STATUS.FAILED);
+		    failExists = true;
+		}
+		break;
+	    default:
+		throw new UnsupportedOperationException(mop.toString());
+	    }
+	}
+	return failExists;
+    }
+
+    @Override
+    public boolean multiRead(final Collection<IMultiEntryOperation> ops) {
+	boolean failExists = false;
+	for (IMultiEntryOperation op : ops) {
+	    IModifiableMultiEntryOperation mop = (IModifiableMultiEntryOperation) op;
+	    HZTable table = (HZTable) op.getTableId();
+	    ((HZMultiEntryOperation) mop.getActualOperation()).setFuture(table.getBackendMap().getAsync(op.getKey()));
+	}
+	for (IMultiEntryOperation op : ops) {
+	    IModifiableMultiEntryOperation mop = (IModifiableMultiEntryOperation) op;
+	    if (mop.hasSucceeded()) {
+		// status update is already done, nothing to do.
+	    } else {
+		failExists = true;
+	    }
+	}
+
+	return failExists;
+    }
+
+    @Override
+    public long VERSION_NONEXISTENT() {
+	return VERSION_NONEXISTENT;
+    }
+
+
+}