摘要 Keepalived 主页
http://www.keepalived.org/
nginx主页
http://nginx.org/
用Keepalived来实现HA功能，实现主从互备，通过VIP来进行切换，nginx来进行对realserver的七层负载均衡或者是cache功能，或者realserver直接对外，通过DNS对VIP进行轮训。
VIP：192.18.1.222
nginx_master：192.18.1.36
nginx_slave：192.18.1.37
下面开始安装keepalived
wget http://www.keepalived.org/software/keepalived-1.1.15.tar.gz
#tar zxvf keepalived-1.1.15.tar.gz
#cd keepalived-1.1.15
#./configure && make && make install
#find / -name keepalived # 查看keepalived位置
#cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
#cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
#mkdir /etc/keepalived
#cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
#cp /usr/local/sbin/keepalived /usr/sbin/
#service keepalived start|stop #做成系统启动服务方便管理.
下面进行keepalived进行配置，拿两台机器进行主从互备配置nginx_master and nginx_slave
Keepalived 主页
http://www.keepalived.org/
nginx主页
http://nginx.org/
用Keepalived来实现HA功能，实现主从互备，通过VIP来进行切换，nginx来进行对realserver的七层负载均衡或者是cache功能，或者realserver直接对外，通过DNS对VIP进行轮训。
VIP：192.18.1.222
nginx_master：192.18.1.36
nginx_slave：192.18.1.37
下面开始安装keepalived
wget http://www.keepalived.org/software/keepalived-1.1.15.tar.gz
#tar zxvf keepalived-1.1.15.tar.gz
#cd keepalived-1.1.15
#./configure && make && make install
#find / -name keepalived # 查看keepalived位置
#cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
#cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
#mkdir /etc/keepalived
#cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/
#cp /usr/local/sbin/keepalived /usr/sbin/
#service keepalived start|stop #做成系统启动服务方便管理.
下面进行keepalived进行配置，拿两台机器进行主从互备配置nginx_master and nginx_slave
nginx_master配置
05 |
notification_email_from keepalived@arezone.cn |
07 |
smtp_connect_timeout 30 |
11 |
vrrp_instance VI_120 { |
nginx_slave的keepalived.conf配置文件
05 |
notification_email_from keepalived@arezone.cn |
07 |
smtp_connect_timeout 30 |
启动keepalived ，ip a 进行查看vip，查看系统日志，有问题解决问题，没问题当然更好，至此keepalived配置完毕。
nginx配置我在这里就不多说了，网上一搜一大堆。此配置我们已经在线上跑了半年多没出过问题，而且很稳定，
简单总结，当nginx_master down机时，192.168.1.36会自动切换到nginx_slave上，当nginx_slave down机时，192.168.1.37会自动切换到nginx_master上，期间不会影响到服务，keepalived切换速度非常快，linux下ping可能会出现丢一个包的情况，一般都是有一跳延迟大一些，但不会丢包，好了先罗嗦到这.
