3、Keepalived一主一从配置架构搭建并实现VIP漂移

[root@ka1 ~]#vim /etc/keepalived/keepalived.conf
global_defs {
   router_id ka1
}

vrrp_instance VI_1 { 
    state MASTER
    interface eth0          
    virtual_router_id 66 
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
       10.0.0.100/24 dev eth0 label eth0:1 
    }
}
[root@ka1 ~]#systemctl restart keepalived.service

[root@ka2 ~]#vim /etc/keepalived/keepalived.conf
global_defs {
   router_id ka2
}

vrrp_instance VI_1 { 
    state BACKUP    
    interface eth0          
    virtual_router_id 66 
    priority 80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
       10.0.0.100/24 dev eth0 label eth0:1 
    }
}
[root@ka2 ~]#systemctl restart keepalived.service

[root@ubuntu2004 ~]#ping 10.0.0.100
PING 10.0.0.100 (10.0.0.100) 56(84) bytes of data.
64 字节，来自 10.0.0.100: icmp_seq=1 ttl=64 时间=1.34 毫秒

[root@ubuntu2004 ~]#arp -n
10.0.0.100               ether   00:0c:29:69:a0:82   C                     eth0
查看MAC地址来源于那个机器
[root@ka1 ~]#ip a
第一台link/ether 00:0c:29:69:a0:82 brd ff:ff:ff:ff:ff:ff
[root@ka2 ~]#ip a
第二台link/ether 00:0c:29:51:27:c8 brd ff:ff:ff:ff:ff:ff

[root@ubuntu2004 ~]#systemctl stop keepalived.service
[root@ubuntu2004 ~]#arp -n
10.0.0.100               ether   00:0c:29:51:27:c8   C                     eth0
MAC地址为第二台机器的地址

[root@ubuntu2004 ~]#systemctl start keepalived.service
[root@ubuntu2004 ~]#arp -n
10.0.0.100               ether   00:0c:29:69:a0:82   C                     eth0

也可抓包观察现象（多播，VIP一直发送自己的状态供其他机器知道，当第一个节点停止时，他的优先级为0，并向外发送自己的状态，这是第二台机器的优先级高，则第二台机器接替第一台工作）
[root@ubuntu2004 ~]#tcpdump -i eth0 -nn host 224.0.0.18