yum install keepalived

vi /etc/keepalived/keepalived.conf

#!/bin/bash

count=0
for (( k=0; k<2; k++ ))
do
   check_code=$( curl --connect-timeout 3 -sL -w "%{http_code}\\n" http://localhost:81 -o /dev/null )
   if [ "$check_code" != "200" ]; then
       count=count +1
       continue
   else
       count = 0
       break
   fi
done
if [ "$count" != "0" ]; then
   killall keepalived
   exit 1
else
   exit 0
fi

vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived
vrrp_script chk_nginx {
   script "/etc/keepalived/check_nginx.sh" # 心跳检测角本
   interval 2 #脚本执行间隔，每2s检测一次
   weight -5 #脚本结果导致的优先级变更，检测失败（脚本返回非0）则优先级 -5
   fall 3 #检测连续2次失败才算确定是真失败。会用weight减少优先级（1-255之间）
   rise 2 #检测1次成功就算成功。但不修改优先级
}

vrrp_instance VI_1 {
   state MASTER #指定keepalived的角色，MASTER表示此主机是主服务器，BACKUP表示此主机是备用服务器
   interface eth0 #指定监测网络的接口。实例绑定的网卡，因为在配置虚拟IP的时候必须是在已有的网卡上添加的
   mcast_src_ip  192.168.0.118 ## 发送多播数据包时的源IP地址
   virtual_router_id 51 #虚拟路由标识，MASTER和BACKUP必须是一致的
   priority 100 #定义优先级，数字越大，优先级越高
   advert_int 2 #设定MASTER与BACKUP负载均衡器之间同步检查的时间间隔，单位是秒
   authentication { #设置验证类型和密码。主从必须一样
       auth_type PASS #设置vrrp验证类型，主要有PASS和AH两种
       auth_pass 1111 #设置vrrp验证密码，在同一个vrrp_instance下，MASTER与BACKUP必须使用相同的密码才能正常通信
   }
   virtual_ipaddress {
       192.168.0.119 #VRRP 虚拟地址 如果有多个VIP，换行填写
   }
   track_script {
      chk_nginx # 心跳脚本，即在 vrrp_script 部分指定的名字
   }
}

! Configuration File for keepalived
vrrp_script chk_nginx {
   script "/etc/keepalived/check_nginx.sh"
   interval 2
   weight -5
}

vrrp_instance VI_1 {
   state BACKUP # 修改
   interface eth0
   mcast_src_ip  192.168.0.105 # 修改 为本机IP
   virtual_router_id 51
   priority 90  #数字变小
   advert_int 2
   authentication {
       auth_type PASS
       auth_pass 1111
   }
   virtual_ipaddress {
       192.168.0.119
   }
   track_script {
      chk_nginx
   }
}

service keepalived start

/usr/local/nginx/sbin/nginx -s reload

curl 192.168.0.119:81

 /usr/local/nginx/sbin/nginx -s stop

 curl 192.168.0.119:81