期间研究了nginx 与 lvs 和haproxy 的区别，各有优劣，对比之下选择了nginx做负载均衡器 nginx+keepalived 保证最前端代理的高可用【注：nginx+keepalived为一级代理，项目使用了二级代理，二级代理为web服务代理】，两台nginx 互为主备，省的备机在哪浪费资源。

nginx 的安装调试就不说了~ keepalived 的安装真的有坑存在！ 当安装配置了keepalived后，开启keepalived后 eth0网卡没有出现配置的虚拟ip

[root@zcy node]# ip addr

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

inet6 ::1/128 scope host 

   valid_lft forever preferred_lft forever

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

link/ether 00:0c:29:7a:91:38 brd ff:ff:ff:ff:ff:ff

inet 192.168.103.51/22 brd 192.168.103.255 scope global eth0

inet6 fe80::20c:29ff:fe7a:9138/64 scope link 

   valid_lft forever preferred_lft forever

查看系统日志

[root@zcy node]# tail -f /var/log/messages

Apr 30 10:41:12 zcy dhclient[1081]: DHCPACK from 192.168.100.1 (xid=0x55592dd3)

Apr 30 10:41:14 zcy dhclient[1081]: bound to 192.168.103.51 -- renewal in 41832 seconds.

Apr 30 12:12:54 zcy Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE

Apr 30 12:12:55 zcy Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE

并没有虚拟IP，显然conf没有执行ok

解决方法： keepalived 虚拟IP 不生效问题

/etc/init.d/keepalived

  start() { 

......省略多行.........

echo -n $"Starting $prog: " 

daemon $exec $KEEPALIVED_OPTIONS 

retval=$? 

......省略多行.........
}

关键是这一行

daemon $exec $KEEPALIVED_OPTIONS

改成

daemon keepalived -D -f $config

如果前面没有定义config变量 就把$config换成配置文件的绝对位置