1、安装nginx

2、用两个虚拟机安装两个reids(reids1、redis2) 其中一个配置slaveof 192.168.1.86 6379（另一个redis的IP与端口）

3、安装两个tomcat

修改tomcat的context.xml：

    <Context>  
      
        <!-- Default set of monitored resources -->  
        <WatchedResource>WEB-INF/web.xml</WatchedResource>  
      
        <!-- Uncomment this to disable session persistence across Tomcat restarts -->  
        <!--
        <Manager pathname="" />
        -->  
      
        <!-- Uncomment this to enable Comet connection tacking (provides events  
             on session expiration as well as webapp lifecycle) -->  
        <!--
        <Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
        -->  
      
      <Valve className="com.orangefunction.tomcat.redissessions.RedisSessionHandlerValve" />  
      <Manager className="com.orangefunction.tomcat.redissessions.RedisSessionManager"  
     host="192.168.1.106"
       port="6379"  (注：一个tomcat设置对应的一个redis的IP与端口)
       database="0"  
       maxInactiveInterval="60" />  
    </Context> 

nginx+redis主从+tomcat一机多实例实现会话共享