当前服务器的IP为192.168.79.128
1、Keepalived下载
https://www.keepalived.org/download.html
我这里下载的是Version 2.0.18
2、Keepalived安装
cd /home/tools/
tar -zxvf keepalived-2.0.18.tar.gz
cd keepalived-2.0.18
./configure --prefix=/usr/loacl/keepalived --sysconf=/etc
make & make install
3、keepalived核心配置文件
cd /etc/keepalived
vi keepalived.conf
修改global_defs
计算机节点配置
4、启动keeepalived
启动前的IP
启动keepalived
cd /usr/local/keepalived/sbin/
./keepalived
启动后的IP
可以发现虚拟IP 192.168.79.161 已经生效
5、将keepalived注册为系统服务
一般要停止Keepalived，需要kill该进程。如何更优雅停止keepalived？可以将keepalived注册为系统服务
cd /home/tools/keepalived-2.0.18/keepalived/etc
cp init.d/keepalived /etc/init.d/
cp sysconfig/keepalived /etc/sysconfig/
使服务生效： systemctl daemon-reload
这样系统服务就可以使用keepalived了
使用systemctl start keepalived.service启动keepalived。
使用systemctl stop keepalived.service停止keepalived。
使用systemctl restart keepalived.service重启keepalived。
6、keepalived实现双机主备
备用节点服务器的IP为192.168.79.129
keepalived配置如下
然后启动keepalived
这里没有192.168.79.161， 说明主节点192.168.79.128运行正常。
window的host配置如下
www.128.com 指向192.168.79.128 主Nginx节点
www.129.com 指向192.168.79.129 备用Nginx节点
www.home.com 指向虚拟ip 192.168.79.161 虚拟IP现在绑定的是主Nginx节点： 192.168.79.128
现在假设主节点挂了，我们停止Keepalived，
使用ip addr，此时已经没有了虚拟IP
进入备用节点，查看IP。可以发现备用节点192.168.79.129多了一个虚拟IP 192.168.79.161
此时www.home.com访问的是129
当主节点Keepalived重新启动后，虚拟IP又跟主节点Niginx绑定了。这样就实现了Nginx双机主备配置了。
原文：https://www.cnblogs.com/linlf03/p/13168740.html