初探 Keepalived 最小化配置跑起来

说明

关于 Keepalived 的用途和目的请自行搜索相关信息, 本文只使用最小化配置使 Keepalived 跑起来, 达到故障时漂移 ip 的目的, 避免单点故障。

安装

yum install keepalived -y

常用命令

# 查看状态
sudo systemctl status keepalived
# 启动
sudo systemctl start keepalived
# 停止
sudo systemctl stop keepalived

默认配置在 /etc/keepalived/keepalived.conf

配置

实例一

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 2
    virtual_ipaddress {
        10.4.82.48
    }
}

实例二

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 101
    advert_int 2
    virtual_ipaddress {
        10.4.82.48
    }
}

配置说明

interface 网卡
priority 优先级
virtual_router_id 保持一致
virtual_ipaddress 虚拟 ip
advert_int 检查频率 单位 秒

实例一

[junbaor@wkfg-1 sbin]$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:a7:cd:93 brd ff:ff:ff:ff:ff:ff
    inet 10.4.82.141/24 brd 10.4.82.255 scope global dynamic ens33
       valid_lft 171585sec preferred_lft 171585sec
    inet 10.4.82.48/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::ce43:fb82:c450:c422/64 scope link 
       valid_lft forever preferred_lft forever

实例二

[junbaor@wkfg-2 sbin]$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:81:c5:4d brd ff:ff:ff:ff:ff:ff
    inet 10.4.82.47/24 brd 10.4.82.255 scope global dynamic ens33
       valid_lft 172728sec preferred_lft 172728sec
    inet6 fe80::40b2:61cf:9620:a5f3/64 scope link 
       valid_lft forever preferred_lft forever
    inet6 fe80::ce43:fb82:c450:c422/64 scope link tentative dadfailed 
       valid_lft forever preferred_lft forever

可以看到虚拟的ip 10.4.82.48 已经漂移到实例一
这时我们关闭实例一或者停止 keepalived 进程, ip 就会和实例二绑定