项目背景
利用lvs的vs/NAT技术实现一个由负载调度器和两个web服务器组成的架构！
试验环境
vmware workstation 11
centos6.5的系统下
load balance：ip：192.168.0.32 vip：192.168.1.32 关闭iptables setenforce0
user：ip：192.168.1.39 关闭iptables setenforce0
real_server01:192.168.0.10 gw:192.168.0.32 关闭iptables setenforce0
real_server02:192.168.0.36 gw:192.168.0.36 关闭iptables setenforce0
SecureCRT （ssh远程连接软件）
架构图：
实验过程：
一、在load balance上面安装ipvsadm
直接用yum安装
因为我已经安装成功了，所以显示已安装！
二、在load balance上面执行脚本
[root@Load_Balancer ~]# cat lvs.sh
#!/bin/sh
#set ip_forward ON for vs-nat director (1 on, 0 off).
cat /proc/sys/net/ipv4/ip_forward
echo "1" >/proc/sys/net/ipv4/ip_forward
#director is gw for realservers
#turn OFF icmp redirects (1 on, 0 off)
echo "0" >/proc/sys/net/ipv4/conf/all/send_redirects
cat /proc/sys/net/ipv4/conf/all/send_redirects
echo "0" >/proc/sys/net/ipv4/conf/default/send_redirects
cat /proc/sys/net/ipv4/conf/default/send_redirects
echo "0" >/proc/sys/net/ipv4/conf/eth0/send_redirects
cat /proc/sys/net/ipv4/conf/eth0/send_redirects
#clear ipvsadm tables
/sbin/ipvsadm -C
#install LVS services with ipvsadm
#add telnet to VIP with rr sheduling
/sbin/ipvsadm -A -t 192.168.1.32:80 -s rr
#first realserver
/sbin/ipvsadm -a -t 192.168.1.32:80 -r 192.168.0.10:80 -m -w 1
#second realserver
#forward telnet to realserver 192.168.0.36 using LVS-NAT (-m), with weight=1
/sbin/ipvsadm -a -t 192.168.1.32:80 -r 192.168.0.36:80 -m -w 1
#list ipvsadm table
/sbin/ipvsadm
三、在real server01上面执行脚本
[root@real_server01 ~]# cat real_server01.sh
#!/bin/sh
#show routing table
/bin/netstat -rn
#set_realserver_ip_forwarding to OFF (1 on, 0 off).
echo "0" >/proc/sys/net/ipv4/ip_forward
cat /proc/sys/net/ipv4/ip_forward
四、在real server02上执行脚本
[root@real_server02 ~]# cat real_server02.sh
#!/bin/sh
#show routing table
/bin/netstat -rn
#set_realserver_ip_forwarding to OFF (1 on, 0 off).
echo "0" >/proc/sys/net/ipv4/ip_forward
cat /proc/sys/net/ipv4/ip_forward
五、测试，在user上打开浏览器输入vip 192.168.1.32
可以看到，我在user服务器上访问load balance上面的vip，可以访问到后端的web集群。
总结：VS/NAT技术是我们呢常用的构建lvs集群的技术，当然你可以在后端部署十几台或者几十台服务器。希望大家都有所得
