Keepalived实验

Keepalived 高可用集群部署与故障切换实验
一、实验说明

本实验结合 LVS/HAProxy 与 Keepalived，实现负载均衡器的主备切换，当主节点故障时，备节点自动接管 VIP，保证服务不中断。
二、知识点讲解

VRRP 协议：Keepalived 基于 VRRP（虚拟路由冗余协议）实现高可用，将多台设备虚拟为一台，选举主节点。

核心功能：

健康检查：检测后端服务器和自身服务状态。

故障切换：主节点故障时，备节点自动升级为主节点，接管 VIP。

配置 LVS：与 LVS 深度集成，自动维护 IPVS 规则。
操作步骤

1、安装 Keepalived

yum install -y keepalived

2、主节点（MASTER）配置 /etc/keepalived/keepalived.conf

global_defs {
    router_id LVS_DEVEL
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.100/24
    }
    track_script {
        check_haproxy
    }
}

vrrp_script check_haproxy {
    script "/etc/keepalived/check_haproxy.sh"
    interval 2
    weight -20
}

3、备节点（BACKUP）配置

global_defs {
    router_id LVS_DEVEL
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.100/24
    }
    track_script {
        check_haproxy
    }
}

vrrp_script check_haproxy {
    script "/etc/keepalived/check_haproxy.sh"
    interval 2
    weight -20
}

4、创建健康检查脚本 /etc/keepalived/check_haproxy.sh

#!/bin/bash
if [ `ps -C haproxy --no-header | wc -l` -eq 0 ]; then
    systemctl stop keepalived
fi

chmod +x /etc/keepalived/check_haproxy.sh

5、启动服务

systemctl start keepalived
systemctl enable keepalived

6、故障切换测试

停止主节点的 HAProxy 服务，观察 VIP 是否漂移到备节点。