Apache2.2新增加了几个module，和tomcat集成更加的简单了：

LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_ajp_module modules/mod_proxy_ajp.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so
LoadModule proxy_http_module modules/mod_proxy_http.so

ProxyRequests Off

ProxyPass / balancer://myCluster/
<Proxy balancer://myCluster/>
       BalancerMember ajp://localhost:10009 route=tomcat1
       BalancerMember ajp://localhost:20009 route=tomcat2
</Proxy>