hbase-server/src/main/java/org/apache/hadoop/hbase/master/ClusterStatusPublisher.java - hbase - Git at Google

 /**
  *
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */


 package org.apache.hadoop.hbase.master;


 import io.netty.bootstrap.Bootstrap;
 import io.netty.bootstrap.ChannelFactory;
 import io.netty.buffer.Unpooled;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelException;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
 import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.channel.socket.DatagramChannel;
 import io.netty.channel.socket.DatagramPacket;
 import io.netty.channel.socket.InternetProtocolFamily;
 import io.netty.channel.socket.nio.NioDatagramChannel;
 import io.netty.handler.codec.MessageToMessageEncoder;
 import io.netty.util.internal.StringUtil;

 import java.io.Closeable;
 import java.io.IOException;
 import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.NetworkInterface;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;

 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.ClusterStatus;
 import org.apache.hadoop.hbase.HBaseInterfaceAudience;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.ScheduledChore;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.protobuf.generated.ClusterStatusProtos;
 import org.apache.hadoop.hbase.util.Addressing;
 import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
 import org.apache.hadoop.hbase.util.ExceptionUtil;
 import org.apache.hadoop.hbase.util.Pair;
 import org.apache.hadoop.hbase.util.ReflectionUtils;
 import org.apache.hadoop.hbase.util.Threads;
 import org.apache.hadoop.hbase.util.VersionInfo;


 /**
  * Class to publish the cluster status to the client. This allows them to know immediately
  *  the dead region servers, hence to cut the connection they have with them, eventually stop
  *  waiting on the socket. This improves the mean time to recover, and as well allows to increase
  *  on the client the different timeouts, as the dead servers will be detected separately.
  */
 @InterfaceAudience.Private
 public class ClusterStatusPublisher extends ScheduledChore {
   /**
    * The implementation class used to publish the status. Default is null (no publish).
    * Use org.apache.hadoop.hbase.master.ClusterStatusPublisher.MulticastPublisher to multicast the
    * status.
    */
   public static final String STATUS_PUBLISHER_CLASS = "hbase.status.publisher.class";
   public static final Class<? extends ClusterStatusPublisher.Publisher>
       DEFAULT_STATUS_PUBLISHER_CLASS =
       org.apache.hadoop.hbase.master.ClusterStatusPublisher.MulticastPublisher.class;

   /**
    * The minimum time between two status messages, in milliseconds.
    */
   public static final String STATUS_PUBLISH_PERIOD = "hbase.status.publish.period";
   public static final int DEFAULT_STATUS_PUBLISH_PERIOD = 10000;

   private long lastMessageTime = 0;
   private final HMaster master;
   private final int messagePeriod; // time between two message
   private final ConcurrentMap<ServerName, Integer> lastSent =
       new ConcurrentHashMap<ServerName, Integer>();
   private Publisher publisher;
   private boolean connected = false;

   /**
    * We want to limit the size of the protobuf message sent, do fit into a single packet.
    * a reasonable size for ip / ethernet is less than 1Kb.
    */
   public final static int MAX_SERVER_PER_MESSAGE = 10;

   /**
    * If a server dies, we're sending the information multiple times in case a receiver misses the
    * message.
    */
   public final static int NB_SEND = 5;

   public ClusterStatusPublisher(HMaster master, Configuration conf,
                                 Class<? extends Publisher> publisherClass)
       throws IOException {
     super("HBase clusterStatusPublisher for " + master.getName(), master, conf.getInt(
       STATUS_PUBLISH_PERIOD, DEFAULT_STATUS_PUBLISH_PERIOD));
     this.master = master;
     this.messagePeriod = conf.getInt(STATUS_PUBLISH_PERIOD, DEFAULT_STATUS_PUBLISH_PERIOD);
     try {
       this.publisher = publisherClass.newInstance();
     } catch (InstantiationException e) {
       throw new IOException("Can't create publisher " + publisherClass.getName(), e);
     } catch (IllegalAccessException e) {
       throw new IOException("Can't create publisher " + publisherClass.getName(), e);
     }
     this.publisher.connect(conf);
     connected = true;
   }

   // For tests only
   protected ClusterStatusPublisher() {
     master = null;
     messagePeriod = 0;
   }

   @Override
   protected void chore() {
     if (!connected) {
       return;
     }

     List<ServerName> sns = generateDeadServersListToSend();
     if (sns.isEmpty()) {
       // Nothing to send. Done.
       return;
     }

     final long curTime = EnvironmentEdgeManager.currentTime();
     if (lastMessageTime > curTime - messagePeriod) {
       // We already sent something less than 10 second ago. Done.
       return;
     }

     // Ok, we're going to send something then.
     lastMessageTime = curTime;

     // We're reusing an existing protobuf message, but we don't send everything.
     // This could be extended in the future, for example if we want to send stuff like the
     //  hbase:meta server name.
     ClusterStatus cs = new ClusterStatus(VersionInfo.getVersion(),
         master.getMasterFileSystem().getClusterId().toString(),
         null,
         sns,
         master.getServerName(),
         null,
         null,
         null,
         null);


     publisher.publish(cs);
   }

   protected void cleanup() {
     connected = false;
     publisher.close();
   }

   /**
    * Create the dead server to send. A dead server is sent NB_SEND times. We send at max
    * MAX_SERVER_PER_MESSAGE at a time. if there are too many dead servers, we send the newly
    * dead first.
    */
   protected List<ServerName> generateDeadServersListToSend() {
     // We're getting the message sent since last time, and add them to the list
     long since = EnvironmentEdgeManager.currentTime() - messagePeriod * 2;
     for (Pair<ServerName, Long> dead : getDeadServers(since)) {
       lastSent.putIfAbsent(dead.getFirst(), 0);
     }

     // We're sending the new deads first.
     List<Map.Entry<ServerName, Integer>> entries = new ArrayList<Map.Entry<ServerName, Integer>>();
     entries.addAll(lastSent.entrySet());
     Collections.sort(entries, new Comparator<Map.Entry<ServerName, Integer>>() {
       @Override
       public int compare(Map.Entry<ServerName, Integer> o1, Map.Entry<ServerName, Integer> o2) {
         return o1.getValue().compareTo(o2.getValue());
       }
     });

     // With a limit of MAX_SERVER_PER_MESSAGE
     int max = entries.size() > MAX_SERVER_PER_MESSAGE ? MAX_SERVER_PER_MESSAGE : entries.size();
     List<ServerName> res = new ArrayList<ServerName>(max);

     for (int i = 0; i < max; i++) {
       Map.Entry<ServerName, Integer> toSend = entries.get(i);
       if (toSend.getValue() >= (NB_SEND - 1)) {
         lastSent.remove(toSend.getKey());
       } else {
         lastSent.replace(toSend.getKey(), toSend.getValue(), toSend.getValue() + 1);
       }

       res.add(toSend.getKey());
     }

     return res;
   }

   /**
    * Get the servers which died since a given timestamp.
    * protected because it can be subclassed by the tests.
    */
   protected List<Pair<ServerName, Long>> getDeadServers(long since) {
     if (master.getServerManager() == null) {
       return Collections.emptyList();
     }

     return master.getServerManager().getDeadServers().copyDeadServersSince(since);
   }


   public interface Publisher extends Closeable {

     void connect(Configuration conf) throws IOException;

     void publish(ClusterStatus cs);

     @Override
     void close();
   }

   @InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
   public static class MulticastPublisher implements Publisher {
     private DatagramChannel channel;
     private final EventLoopGroup group = new NioEventLoopGroup(
         1, Threads.newDaemonThreadFactory("hbase-master-clusterStatusPublisher"));

     public MulticastPublisher() {
     }

     @Override
     public void connect(Configuration conf) throws IOException {
       String mcAddress = conf.get(HConstants.STATUS_MULTICAST_ADDRESS,
           HConstants.DEFAULT_STATUS_MULTICAST_ADDRESS);
       int port = conf.getInt(HConstants.STATUS_MULTICAST_PORT,
           HConstants.DEFAULT_STATUS_MULTICAST_PORT);

       final InetAddress ina;
       try {
         ina = InetAddress.getByName(mcAddress);
       } catch (UnknownHostException e) {
         close();
         throw new IOException("Can't connect to " + mcAddress, e);
       }

       final InetSocketAddress isa = new InetSocketAddress(mcAddress, port);

       InternetProtocolFamily family;
       InetAddress localAddress;
       if (ina instanceof Inet6Address) {
         localAddress = Addressing.getIp6Address();
         family = InternetProtocolFamily.IPv6;
       }else{
         localAddress = Addressing.getIp4Address();
         family = InternetProtocolFamily.IPv4;
       }
       NetworkInterface ni = NetworkInterface.getByInetAddress(localAddress);

       Bootstrap b = new Bootstrap();
       b.group(group)
       .channelFactory(new HBaseDatagramChannelFactory<Channel>(NioDatagramChannel.class, family))
       .option(ChannelOption.SO_REUSEADDR, true)
       .handler(new ClusterStatusEncoder(isa));

       try {
         channel = (DatagramChannel) b.bind(new InetSocketAddress(0)).sync().channel();
         channel.joinGroup(ina, ni, null, channel.newPromise()).sync();
         channel.connect(isa).sync();
       } catch (InterruptedException e) {
         close();
         throw ExceptionUtil.asInterrupt(e);
       }
     }

     private static final class HBaseDatagramChannelFactory<T extends Channel> implements ChannelFactory<T> {
       private final Class<? extends T> clazz;
       private InternetProtocolFamily family;

       HBaseDatagramChannelFactory(Class<? extends T> clazz, InternetProtocolFamily family) {
           this.clazz = clazz;
           this.family = family;
       }

       @Override
       public T newChannel() {
           try {
             return ReflectionUtils.instantiateWithCustomCtor(clazz.getName(),
               new Class[] { InternetProtocolFamily.class }, new Object[] { family });

           } catch (Throwable t) {
               throw new ChannelException("Unable to create Channel from class " + clazz, t);
           }
       }

       @Override
       public String toString() {
           return StringUtil.simpleClassName(clazz) + ".class";
       }
   }

     private static class ClusterStatusEncoder extends MessageToMessageEncoder<ClusterStatus> {
       final private InetSocketAddress isa;

       private ClusterStatusEncoder(InetSocketAddress isa) {
         this.isa = isa;
       }

       @Override
       protected void encode(ChannelHandlerContext channelHandlerContext,
                             ClusterStatus clusterStatus, List<Object> objects) {
         ClusterStatusProtos.ClusterStatus csp = ProtobufUtil.convert(clusterStatus);
         objects.add(new DatagramPacket(Unpooled.wrappedBuffer(csp.toByteArray()), isa));
       }
     }

     @Override
     public void publish(ClusterStatus cs) {
       channel.writeAndFlush(cs).syncUninterruptibly();
     }

     @Override
     public void close() {
       if (channel != null) {
         channel.close();
       }
       group.shutdownGracefully();
     }
   }
 }
	/**
	*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/


	package org.apache.hadoop.hbase.master;


	import io.netty.bootstrap.Bootstrap;
	import io.netty.bootstrap.ChannelFactory;
	import io.netty.buffer.Unpooled;
	import io.netty.channel.Channel;
	import io.netty.channel.ChannelException;
	import io.netty.channel.ChannelHandlerContext;
	import io.netty.channel.ChannelOption;
	import io.netty.channel.EventLoopGroup;
	import io.netty.channel.nio.NioEventLoopGroup;
	import io.netty.channel.socket.DatagramChannel;
	import io.netty.channel.socket.DatagramPacket;
	import io.netty.channel.socket.InternetProtocolFamily;
	import io.netty.channel.socket.nio.NioDatagramChannel;
	import io.netty.handler.codec.MessageToMessageEncoder;
	import io.netty.util.internal.StringUtil;

	import java.io.Closeable;
	import java.io.IOException;
	import java.net.Inet6Address;
	import java.net.InetAddress;
	import java.net.InetSocketAddress;
	import java.net.NetworkInterface;
	import java.net.UnknownHostException;
	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Comparator;
	import java.util.List;
	import java.util.Map;
	import java.util.concurrent.ConcurrentHashMap;
	import java.util.concurrent.ConcurrentMap;

	import org.apache.hadoop.conf.Configuration;
	import org.apache.hadoop.hbase.ClusterStatus;
	import org.apache.hadoop.hbase.HBaseInterfaceAudience;
	import org.apache.hadoop.hbase.HConstants;
	import org.apache.hadoop.hbase.ScheduledChore;
	import org.apache.hadoop.hbase.ServerName;
	import org.apache.hadoop.hbase.classification.InterfaceAudience;
	import org.apache.hadoop.hbase.protobuf.ProtobufUtil;
	import org.apache.hadoop.hbase.protobuf.generated.ClusterStatusProtos;
	import org.apache.hadoop.hbase.util.Addressing;
	import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
	import org.apache.hadoop.hbase.util.ExceptionUtil;
	import org.apache.hadoop.hbase.util.Pair;
	import org.apache.hadoop.hbase.util.ReflectionUtils;
	import org.apache.hadoop.hbase.util.Threads;
	import org.apache.hadoop.hbase.util.VersionInfo;


	/**
	* Class to publish the cluster status to the client. This allows them to know immediately
	* the dead region servers, hence to cut the connection they have with them, eventually stop
	* waiting on the socket. This improves the mean time to recover, and as well allows to increase
	* on the client the different timeouts, as the dead servers will be detected separately.
	*/
	@InterfaceAudience.Private
	public class ClusterStatusPublisher extends ScheduledChore {
	/**
	* The implementation class used to publish the status. Default is null (no publish).
	* Use org.apache.hadoop.hbase.master.ClusterStatusPublisher.MulticastPublisher to multicast the
	* status.
	*/
	public static final String STATUS_PUBLISHER_CLASS = "hbase.status.publisher.class";
	public static final Class<? extends ClusterStatusPublisher.Publisher>
	DEFAULT_STATUS_PUBLISHER_CLASS =
	org.apache.hadoop.hbase.master.ClusterStatusPublisher.MulticastPublisher.class;

	/**
	* The minimum time between two status messages, in milliseconds.
	*/
	public static final String STATUS_PUBLISH_PERIOD = "hbase.status.publish.period";
	public static final int DEFAULT_STATUS_PUBLISH_PERIOD = 10000;

	private long lastMessageTime = 0;
	private final HMaster master;
	private final int messagePeriod; // time between two message
	private final ConcurrentMap<ServerName, Integer> lastSent =
	new ConcurrentHashMap<ServerName, Integer>();
	private Publisher publisher;
	private boolean connected = false;

	/**
	* We want to limit the size of the protobuf message sent, do fit into a single packet.
	* a reasonable size for ip / ethernet is less than 1Kb.
	*/
	public final static int MAX_SERVER_PER_MESSAGE = 10;

	/**
	* If a server dies, we're sending the information multiple times in case a receiver misses the
	* message.
	*/
	public final static int NB_SEND = 5;

	public ClusterStatusPublisher(HMaster master, Configuration conf,
	Class<? extends Publisher> publisherClass)
	throws IOException {
	super("HBase clusterStatusPublisher for " + master.getName(), master, conf.getInt(
	STATUS_PUBLISH_PERIOD, DEFAULT_STATUS_PUBLISH_PERIOD));
	this.master = master;
	this.messagePeriod = conf.getInt(STATUS_PUBLISH_PERIOD, DEFAULT_STATUS_PUBLISH_PERIOD);
	try {
	this.publisher = publisherClass.newInstance();
	} catch (InstantiationException e) {
	throw new IOException("Can't create publisher " + publisherClass.getName(), e);
	} catch (IllegalAccessException e) {
	throw new IOException("Can't create publisher " + publisherClass.getName(), e);
	}
	this.publisher.connect(conf);
	connected = true;
	}

	// For tests only
	protected ClusterStatusPublisher() {
	master = null;
	messagePeriod = 0;
	}

	@Override
	protected void chore() {
	if (!connected) {
	return;
	}

	List<ServerName> sns = generateDeadServersListToSend();
	if (sns.isEmpty()) {
	// Nothing to send. Done.
	return;
	}

	final long curTime = EnvironmentEdgeManager.currentTime();
	if (lastMessageTime > curTime - messagePeriod) {
	// We already sent something less than 10 second ago. Done.
	return;
	}

	// Ok, we're going to send something then.
	lastMessageTime = curTime;

	// We're reusing an existing protobuf message, but we don't send everything.
	// This could be extended in the future, for example if we want to send stuff like the
	// hbase:meta server name.
	ClusterStatus cs = new ClusterStatus(VersionInfo.getVersion(),
	master.getMasterFileSystem().getClusterId().toString(),
	null,
	sns,
	master.getServerName(),
	null,
	null,
	null,
	null);


	publisher.publish(cs);
	}

	protected void cleanup() {
	connected = false;
	publisher.close();
	}

	/**
	* Create the dead server to send. A dead server is sent NB_SEND times. We send at max
	* MAX_SERVER_PER_MESSAGE at a time. if there are too many dead servers, we send the newly
	* dead first.
	*/
	protected List<ServerName> generateDeadServersListToSend() {
	// We're getting the message sent since last time, and add them to the list
	long since = EnvironmentEdgeManager.currentTime() - messagePeriod * 2;
	for (Pair<ServerName, Long> dead : getDeadServers(since)) {
	lastSent.putIfAbsent(dead.getFirst(), 0);
	}

	// We're sending the new deads first.
	List<Map.Entry<ServerName, Integer>> entries = new ArrayList<Map.Entry<ServerName, Integer>>();
	entries.addAll(lastSent.entrySet());
	Collections.sort(entries, new Comparator<Map.Entry<ServerName, Integer>>() {
	@Override
	public int compare(Map.Entry<ServerName, Integer> o1, Map.Entry<ServerName, Integer> o2) {
	return o1.getValue().compareTo(o2.getValue());
	}
	});

	// With a limit of MAX_SERVER_PER_MESSAGE
	int max = entries.size() > MAX_SERVER_PER_MESSAGE ? MAX_SERVER_PER_MESSAGE : entries.size();
	List<ServerName> res = new ArrayList<ServerName>(max);

	for (int i = 0; i < max; i++) {
	Map.Entry<ServerName, Integer> toSend = entries.get(i);
	if (toSend.getValue() >= (NB_SEND - 1)) {
	lastSent.remove(toSend.getKey());
	} else {
	lastSent.replace(toSend.getKey(), toSend.getValue(), toSend.getValue() + 1);
	}

	res.add(toSend.getKey());
	}

	return res;
	}

	/**
	* Get the servers which died since a given timestamp.
	* protected because it can be subclassed by the tests.
	*/
	protected List<Pair<ServerName, Long>> getDeadServers(long since) {
	if (master.getServerManager() == null) {
	return Collections.emptyList();
	}

	return master.getServerManager().getDeadServers().copyDeadServersSince(since);
	}


	public interface Publisher extends Closeable {

	void connect(Configuration conf) throws IOException;

	void publish(ClusterStatus cs);

	@Override
	void close();
	}

	@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
	public static class MulticastPublisher implements Publisher {
	private DatagramChannel channel;
	private final EventLoopGroup group = new NioEventLoopGroup(
	1, Threads.newDaemonThreadFactory("hbase-master-clusterStatusPublisher"));

	public MulticastPublisher() {
	}

	@Override
	public void connect(Configuration conf) throws IOException {
	String mcAddress = conf.get(HConstants.STATUS_MULTICAST_ADDRESS,
	HConstants.DEFAULT_STATUS_MULTICAST_ADDRESS);
	int port = conf.getInt(HConstants.STATUS_MULTICAST_PORT,
	HConstants.DEFAULT_STATUS_MULTICAST_PORT);

	final InetAddress ina;
	try {
	ina = InetAddress.getByName(mcAddress);
	} catch (UnknownHostException e) {
	close();
	throw new IOException("Can't connect to " + mcAddress, e);
	}

	final InetSocketAddress isa = new InetSocketAddress(mcAddress, port);

	InternetProtocolFamily family;
	InetAddress localAddress;
	if (ina instanceof Inet6Address) {
	localAddress = Addressing.getIp6Address();
	family = InternetProtocolFamily.IPv6;
	}else{
	localAddress = Addressing.getIp4Address();
	family = InternetProtocolFamily.IPv4;
	}
	NetworkInterface ni = NetworkInterface.getByInetAddress(localAddress);

	Bootstrap b = new Bootstrap();
	b.group(group)
	.channelFactory(new HBaseDatagramChannelFactory<Channel>(NioDatagramChannel.class, family))
	.option(ChannelOption.SO_REUSEADDR, true)
	.handler(new ClusterStatusEncoder(isa));

	try {
	channel = (DatagramChannel) b.bind(new InetSocketAddress(0)).sync().channel();
	channel.joinGroup(ina, ni, null, channel.newPromise()).sync();
	channel.connect(isa).sync();
	} catch (InterruptedException e) {
	close();
	throw ExceptionUtil.asInterrupt(e);
	}
	}

	private static final class HBaseDatagramChannelFactory<T extends Channel> implements ChannelFactory<T> {
	private final Class<? extends T> clazz;
	private InternetProtocolFamily family;

	HBaseDatagramChannelFactory(Class<? extends T> clazz, InternetProtocolFamily family) {
	this.clazz = clazz;
	this.family = family;
	}

	@Override
	public T newChannel() {
	try {
	return ReflectionUtils.instantiateWithCustomCtor(clazz.getName(),
	new Class[] { InternetProtocolFamily.class }, new Object[] { family });

	} catch (Throwable t) {
	throw new ChannelException("Unable to create Channel from class " + clazz, t);
	}
	}

	@Override
	public String toString() {
	return StringUtil.simpleClassName(clazz) + ".class";
	}
	}

	private static class ClusterStatusEncoder extends MessageToMessageEncoder<ClusterStatus> {
	final private InetSocketAddress isa;

	private ClusterStatusEncoder(InetSocketAddress isa) {
	this.isa = isa;
	}

	@Override
	protected void encode(ChannelHandlerContext channelHandlerContext,
	ClusterStatus clusterStatus, List<Object> objects) {
	ClusterStatusProtos.ClusterStatus csp = ProtobufUtil.convert(clusterStatus);
	objects.add(new DatagramPacket(Unpooled.wrappedBuffer(csp.toByteArray()), isa));
	}
	}

	@Override
	public void publish(ClusterStatus cs) {
	channel.writeAndFlush(cs).syncUninterruptibly();
	}

	@Override
	public void close() {
	if (channel != null) {
	channel.close();
	}
	group.shutdownGracefully();
	}
	}
	}