linux+nginx+tomcat负载均衡，实现session同步

软件及环境是：
虚拟机上装centos 5.5
IP为：192.168.0.51 装上nginx和tomcat  6.0.32 命名为 Tomcat1
一台win7上装tomcat  6.0.32  IP为：192.168.0.50  命名为 Tomcat2

首先装nginx，我是参照http://blog.s135.com/nginx_php_v6/ 配了一个Nginx + PHP（FastCGI）环境，然后再加上Tomcat的转发。具体配置已略！

下一步是配置Tomcat集群。分别打开tomcat1和tomcat2下conf中server.xml
<Server port="8005" shutdown="SHUTDOWN">
<!-- Define a non-SSL HTTP/1.1 Connector on port 8080 -->
<Connector port="8080" maxHttpHeaderSize="8192"
   maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
   enableLookups="false" redirectPort="8443" acceptCount="100"
   connectionTimeout="20000" disableUploadTimeout="true" />
<!-- Define an AJP 1.3 Connector on port 8009 -->
<Connector port="8009" enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />

找到<Engine name="Catalina" defaultHost="localhost">
Tomcat1下的修改为<Engine name="Catalina" defaultHost="localhost" jvmRoute="tomcat1">
Tomcat2下的修改为<Engine name="Catalina" defaultHost="localhost" jvmRoute="tomcat2">

tomcat1找到
<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
修改为 

< Cluster className = " org.apache.catalina.ha.tcp.SimpleTcpCluster "  
            channelSendOptions = " 6 " >

             < Manager className = " org.apache.catalina.ha.session.DeltaManager "
                expireSessionsOnShutdown = " false "
                notifyListenersOnReplication = " true " />
             <!--
             < Manager className = " org.apache.catalina.ha.session.BackupManager "
                expireSessionsOnShutdown = " false "
                notifyListenersOnReplication = " true "
                mapSendOptions = " 6 " />
             -->
             < Channel className = " org.apache.catalina.tribes.group.GroupChannel " >
                 < Membership className = " org.apache.catalina.tribes.membership.McastService "  
                    address = " 228.0.0.5 "  
                    bind = " 192.168.0.51 "  
                    port = " 45564 "  
                    frequency = " 500 "  
                    dropTime = " 3000 " />
                 < Receiver className = " org.apache.catalina.tribes.transport.nio.NioReceiver "  
                    address = " 192.168.0.51 "  
                    autoBind = " 100 "  
                    port = " 4001 "  
                    selectorTimeout = " 100 "  
                    maxThreads = " 6 " />
                 < Sender className = " org.apache.catalina.tribes.transport.ReplicationTransmitter " >
                     < Transport className = " org.apache.catalina.tribes.transport.nio.PooledParallelSender " />
                 </ Sender >
                 < Interceptor className = " org.apache.catalina.tribes.group.interceptors.TcpFailureDetector " />
                 < Interceptor className = " org.apache.catalina.tribes.group.interceptors.MessageDispatch15Interceptor " />
             </ Channel >
             < Valve className = " org.apache.catalina.ha.tcp.ReplicationValve "  filter = " .*\.gif;.*\.js;.*\.jpg;.*\.png;.*\.htm;.*\.html;.*\.css;.*\.txt; " />
            
             < ClusterListener className = " org.apache.catalina.ha.session.JvmRouteSessionIDBinderListener " />
             < ClusterListener className = " org.apache.catalina.ha.session.ClusterSessionListener " />
         </ Cluster >

tomcat2找到
<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
修改为 

< Cluster className = " org.apache.catalina.ha.tcp.SimpleTcpCluster "  
            channelSendOptions = " 6 " >

             < Manager className = " org.apache.catalina.ha.session.DeltaManager "
                expireSessionsOnShutdown = " false "
                notifyListenersOnReplication = " true " />
             <!--
             < Manager className = " org.apache.catalina.ha.session.BackupManager "
                expireSessionsOnShutdown = " false "
                notifyListenersOnReplication = " true "
                mapSendOptions = " 6 " />
             -->
             < Channel className = " org.apache.catalina.tribes.group.GroupChannel " >
                 < Membership className = " org.apache.catalina.tribes.membership.McastService "  
                    address = " 228.0.0.5 "  
                    bind = " 192.168.0.50 "  
                    port = " 45564 "  
                    frequency = " 500 "  
                    dropTime = " 3000 " />
                 < Receiver className = " org.apache.catalina.tribes.transport.nio.NioReceiver "  
                    address = " 192.168.0.50 "  
                    autoBind = " 100 "  
                    port = " 4000 "  
                    selectorTimeout = " 100 "  
                    maxThreads = " 6 " />
                 < Sender className = " org.apache.catalina.tribes.transport.ReplicationTransmitter " >
                     < Transport className = " org.apache.catalina.tribes.transport.nio.PooledParallelSender " />
                 </ Sender >
                 < Interceptor className = " org.apache.catalina.tribes.group.interceptors.TcpFailureDetector " />
                 < Interceptor className = " org.apache.catalina.tribes.group.interceptors.MessageDispatch15Interceptor " />
             </ Channel >
             < Valve className = " org.apache.catalina.ha.tcp.ReplicationValve "  filter = " .*\.gif;.*\.js;.*\.jpg;.*\.png;.*\.htm;.*\.html;.*\.css;.*\.txt; " />
            
             < ClusterListener className = " org.apache.catalina.ha.session.JvmRouteSessionIDBinderListener " />
             < ClusterListener className = " org.apache.catalina.ha.session.ClusterSessionListener " />
         </ Cluster >

还需要在程序的web.xml里面</web-app>前面加入以下这句话
<distributable/> 
session同步到这里设置完毕

服务器的启动顺序如下: 
tomcat1 --> |tomcat2 --> |nginx 

先启动tocmat1,等tomcat1启动完全的时候再启动tomcat2，等两个tocmat全启动之后，再启动nginx

负载的时候可以用APACHE或NGINX，如果什么都不用，两台一接防问了话，可能会出错极session不同步的问题，网上也很多人介意不要做seeeion同步，这样会降低机器的性能，有一个方法可以，就是NGINX的ip_hash,这样至少可以保证客户端去防问同一台TOCMAT，除非那台TOCMAT挂了

 

原文出自：http://www.blogjava.net/Alpha/archive/2011/06/21/352745.html