这里主要是写怎么配置，不过多的介绍怎么安装和原理性以及理论的东西，如果需要学习这些知识：推荐博文：https://www.cnblogs.com/clsn/p/8052649.html

0、这里使用的版本是：keepalived-2.0.18

#网口信息如下：
[root@keepalived-2 ~]# ifconfig 
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.2.154  netmask 255.255.255.0  broadcast 192.168.2.255
        inet6 fe80::ba2e:3184:84f:b768  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:1b:ac:7a  txqueuelen 1000  (Ethernet)
        RX packets 18030  bytes 1326828 (1.2 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 16786  bytes 1284842 (1.2 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens37: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.186.141  netmask 255.255.255.0  broadcast 192.168.186.255
        inet6 fe80::c37c:f811:9ee4:15bd  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:1b:ac:84  txqueuelen 1000  (Ethernet)
        RX packets 711  bytes 69470 (67.8 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 334  bytes 28146 (27.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

 1、主-keepalived配置

[root@keepalived-1 ~]# cat /usr/local/keepalived-2.0.18/etc/keepalived/keepalived.conf 
! Configuration File for keepalived
! extra script call demonstration
! scripts are supported in Instance and groups
! declarations.

global_defs {
   router_id K_1
   script_user root  
}

! 定义监控脚本位置
vrrp_script chk_nginx {
     script "/usr/local/keepalived-2.0.18/script/check_nginx.sh"
       interval 1 
       weight 2
       fall 3
       rise 1
}

! 注意 virtual_router_id必须一致,priority数值越高，越优先
vrrp_instance VI_1 {
    state MASTER
    interface ens33 ens37
    smtp_alert
    virtual_router_id 1
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass iVZWO
    }

! 配置虚拟IP地址
    virtual_ipaddress {
        192.168.2.200/24 dev ens33
        192.168.186.200/24 dev ens37
    }

! 这里是上面检测脚本的名称
    track_script{
       chk_nginx
    }
}

  2、备-keepalived配置

[root@keepalived-2 ~]# cat /usr/local/keepalived-2.0.18/etc/keepalived/keepalived.conf 
! Configuration File for keepalived
! extra script call demonstration
! scripts are supported in Instance and groups
! declarations.

global_defs {
   router_id K_2
   script_user root  
}

! 定义监控脚本位置
vrrp_script chk_nginx {
     script "/usr/local/keepalived-2.0.18/script/check_nginx.sh"
       interval 1 
       weight 2
       fall 3
       rise 1
}

! 注意 virtual_router_id不能重复,priority优先级比主的低
vrrp_instance VI_1 {
    state BACKUP
    interface ens33 ens37
    smtp_alert
    virtual_router_id 1
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass iVZWO
    }

! 配置虚拟IP地址
    virtual_ipaddress {
        192.168.2.200/24 dev ens33
        192.168.186.200/24 dev ens37
    }
    ! 这里是上面检测脚本的名称
    track_script{
       chk_nginx
    }
}

 3、配置完成后，重启keepalived的服务

#主的服务器
[root@keepalived-1 ~]# /etc/init.d/keepalived restart

#备的服务器
[root@keepalived-2 ~]# /etc/init.d/keepalived restart

4、检查VIP是生成

[root@keepalived-1 ~]#  ip addr | grep "200"
    inet 192.168.2.200/24 scope global secondary ens33
    inet 192.168.186.200/24 scope global secondary ens37

[root@keepalived-2 ~]#  ip addr | grep "200"