安装keepalived

yum -y install keepalived

启动与自启keepalived

systemctl start keepalived
systemctl enable keepalived

修改配置文件

vim /etc/keepalived/keepalived.conf

主节点

! Configuration File for keepalived

vrrp_instance VI_1 {
    state MASTER # 指定初始状态（由priority高低决定）
    interface ens33 # VIP绑定的网卡
    virtual_router_id 51 # 相同的 VRID 为一个组
    priority 100 # 设置优先级，优先级高的为 master
    advert_int 1 # 检查间隔，默认为 1 秒
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.0.144 # VIP
    }
}

从节点

! Configuration File for keepalived

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.0.144
    }
}

两个节点修改完配置文件后，重启keepalived服务。

systemctl restart keepalived

效果

VIP 出现在主节点上

主节点上出现VIP。当停止主节点上的keepalived时，从节点出现 VIP；当停止从节点上的 keepalived 并恢复主节点的 keepalived 时，主节点出现VIP。即VIP在两个节点之间会浮动。
VIP可以ping通

注意点

virtual_router_id必须设置，否则keepalived会异常退出。

参考资料

keepalived主备VIP配置