单机百万连接调优(Netty Demo)

Netty Demo

Constant.java

    public class Constant {
        static final int BEGIN_PORT = 8000; 
        static final int N_PORT = 100;
    }

ConnectionCountHandler.java

import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

@Sharable
public class ConnectionCountHandler extends ChannelInboundHandlerAdapter {

    private AtomicInteger nConnection = new AtomicInteger();

    public ConnectionCountHandler() {
        Executors.newSingleThreadScheduledExecutor().scheduleAtFixedRate(() -> {
            System.out.println("connections: " + nConnection.get());
        }, 0, 2, TimeUnit.SECONDS);

    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        nConnection.incrementAndGet();
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) {
        nConnection.decrementAndGet();
    }

}

Client.class

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;

public class Client {

    private static final String SERVER_HOST = "192.168.1.121";

    public static void main(String[] args) {
        new Client().start(BEGIN_PORT, N_PORT);
    }

    public void start(final int beginPort, int nPort) {
        System.out.println("client starting....");
        EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
        final Bootstrap bootstrap = new Bootstrap();
        bootstrap.group(eventLoopGroup);
        bootstrap.channel(NioSocketChannel.class);
        bootstrap.option(ChannelOption.SO_REUSEADDR, true);
        bootstrap.handler(new ChannelInitializer() {
            @Override
            protected void initChannel(SocketChannel ch) {
            }
        });


        int index = 0;
        int port;
        while (!Thread.interrupted()) {
            port = beginPort + index;
            try {
                ChannelFuture channelFuture = bootstrap.connect(SERVER_HOST, port);
                channelFuture.addListener((ChannelFutureListener) future -> {
                    if (!future.isSuccess()) {
                        System.out.println("connect failed, exit!");
                        System.exit(0);
                    }
                });
                channelFuture.get();
            } catch (Exception e) {
            }

            if (++index == nPort) {
                index = 0;
            }
        }
    }
}

server.java

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;

public final class Server {

    public static void main(String[] args) {
        new Server().start(BEGIN_PORT, N_PORT);
    }

    public void start(int beginPort, int nPort) {
        System.out.println("server starting....");

        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        ServerBootstrap bootstrap = new ServerBootstrap();
        bootstrap.group(bossGroup, workerGroup);
        bootstrap.channel(NioServerSocketChannel.class);
        bootstrap.childOption(ChannelOption.SO_REUSEADDR, true);

        bootstrap.childHandler(new ConnectionCountHandler());


        for (int i = 0; i < nPort; i++) {
            int port = beginPort + i;
            bootstrap.bind(port).addListener((ChannelFutureListener) future -> {
                System.out.println("bind success in port: " + port);
            });
        }
        System.out.println("server started!");
    }
}

调优方案

突破局部文件句柄限制

1. 查看当前局部文件句柄限制

ulimit -n

2. 修改文件

sudo vim /etc/security/limits.conf

3. 添加内容:

*		hard		nofile		1000000
*		soft		nofile		1000000

注：*表示只对当前用户有效，修改之后，机器需要重启

突破全局文件句柄限制

1. 查看全局文件句柄限制

cat /proc/sys/fs/file-max

2. 临时修改

echo 1000000 > /proc/sys/fs/file-max
注：echo方式可以实现即时修改，但机器重启后会失效

3. 永久修改

sudo vim /etc/sysctl.conf

4. 文件末尾，添加内容

fs.file-max = 1000000

5. 使更改生效

sudo sysctl -p
注：完成上述命令后，机器需要重启

参考

Netty_单机百万连接调优
单服务器最大tcp连接数及调优汇总