一、Keepalived 核心理论

1 定义与定位

Keepalived 是开源 Linux 路由软件，核心提供负载均衡与高可用能力，适配 Nginx、MySQL 等各类服务，适用于轻量级无数据同步的高可用场景，最初专为 LVS 设计，现已突破 LVS 生态限制。

2 核心特性

  • 高可用核心：基于 VRRP 协议，解决静态路由单点故障，保障关键服务不中断。
  • 负载均衡：依赖 IPVS 模块实现四层负载均衡，支持多种调度算法，仅向健康节点分发流量。
  • 健康检查：支持 ICMP、TCP 端口、HTTP/HTTPS 及自定义脚本检测，故障节点自动剔除、恢复后自动加入。
  • 快速响应：集成 BFD 协议，故障切换延迟控制在秒级，实现服务无缝衔接。
  • 灵活可扩展：支持多播/单播，可自定义脚本，开源可扩展源码。

3 核心组件

采用模块化设计，核心由三大模块+辅助组件构成：

  1. Core 核心模块：启动维护主进程，解析配置文件，协调各模块工作。
  2. VRRP 协议模块：实现主备选举、状态同步、VIP 绑定/释放，是高可用核心。
  3. Check 健康检查模块：监控节点与服务状态，同步结果给 VRRP 模块作为切换依据。
  4. 辅助组件：含 IPVS 管理、邮件告警等，提升运维便利性。

4 应用场景

核心价值是消除单点故障，典型场景：Web 服务、负载均衡器、数据库、网络设备的高可用冗余。

二、Keepalived 核心原理

1 底层核心：VRRP 协议详解

VRRP 是 Keepalived 高可用底层协议，核心是将多台物理节点虚拟为一个逻辑虚拟路由器，通过选举机制避免单点故障。

1.1 VRRP 核心概念

  • 虚拟路由器：多节点逻辑集合，含唯一 VRID，主备节点 VRID 需一致。
  • VIP：统一访问入口，正常由主节点绑定，备节点不绑定。
  • 主/备节点：主节点优先级最高，处理流量并发送通告；备节点待命，主节点故障时升级。
  • VRRP 通告报文：主节点周期性发送，用于状态同步，默认多播地址 224.0.0.18。

1.2 VRRP 选举机制

核心依据优先级（数值越大越高，默认 100），分初始选举（优先级最高者为 Master）和故障重选（备节点超时未收报文则重选），默认开启抢占模式。

2 Keepalived 工作流程（高可用）

以双节点主备为例，分4阶段，全程自动化：

  1. 初始化：启动服务，解析配置，选举 Master（绑定 VIP）和 Backup（待命）。
  2. 状态维护：Master 周期性发送通告，Backup 监听；Check 模块持续检测健康状态。
  3. 故障切换：Master 故障停发通告，Backup 超时升级为 Master，绑定 VIP 接管流量（切换耗时 1-3 秒）。
  4. 故障恢复：原 Master 恢复后，开启抢占则重获 Master 角色，否则保持 Backup 状态。

3 健康检查原理

分节点检测（基于 VRRP 心跳，检测节点/进程存活）和服务检测（TCP 端口、HTTP 等），检测结果直接影响 VRRP 选举，确保切换后服务可用。

4 负载均衡原理（基于 IPVS）

Master 节点通过 IPVS 配置虚拟服务器与后端节点，客户端请求经 VIP 转发至健康节点；Master 故障时，Backup 同步 IPVS 配置，继续提供服务。

5 常见问题：脑裂

主备同时认为自己是 Master，核心原因是通信链路中断；规避方案：单播配置、冗余链路、脑裂检测脚本、邮件告警。

三、Keepalived基础与进阶实验

笔记时间：2026-01-28

1 基础准备：实验环境搭建

1.1 实验环境拓扑图

1.2 实验环境具体配置步骤

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#部署rs1和rh2（单网卡NAT模式）
[root@rs1 ~]# vmset.sh rs1 eth0 172.25.254.10 
[root@rs1 ~]# dnf install httpd -y
[root@rs1 ~]# echo RS1 - 172.25.254.10 > /var/www/html/index.html
[root@rs1 ~]# systemctl enable --now httpd

[root@rs2 ~]# vmset.sh rs2 eth0 172.25.254.20 
[root@rs2 ~]# dnf install httpd -y
[root@rs2 ~]# echo RS2 - 172.25.254.20 > /var/www/html/index.html
[root@rs2 ~]# systemctl enable --now httpd


#测试：
[Administrator.DESKTOP-VJ307M3] ➤ curl 172.25.254.10
RS1 - 172.25.254.10
                                                                                                    ✔
─────────────────────────────────────────────────────────────────────────────────────────────────────
[2026-01-28 10:36.42]  ~
[Administrator.DESKTOP-VJ307M3] ➤ curl 172.25.254.20
RS2 - 172.25.254.20



#设定ka1和ka2
[root@KA1 ~]# vmset.sh KA1 eth0 172.25.254.50 
[root@KA2 ~]# vmset.sh KA2 eth0 172.25.254.60 


#设定本地解析
[root@KA1 ~]# vim /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
172.25.254.50     KA1
172.25.254.60     KA2
172.25.254.10     rs1
172.25.254.20     rs2


[root@KA1 ~]# for i in 60 10 20; do scp /etc/hosts 172.25.254.$i:/etc/hosts; done

#在所有主机中查看/etc/hosts


#在ka1中开启时间同步服务
[root@KA1 ~]# vim /etc/chrony.conf
 26 allow 0.0.0.0/0
 29 local stratum 10
 
[root@KA1 ~]# systemctl restart chronyd
[root@KA1 ~]# systemctl enable --now chronyd



#在ka2中使用ka1的时间同步服务
[root@KA2 ~]# vim /etc/chrony.conf
pool 172.25.254.50 iburst

[root@KA2 ~]# systemctl restart chronyd
[root@KA2 ~]# systemctl enable --now chronyd

[root@KA2 ~]# chronyc sources -v

  .-- Source mode  '^' = server, '=' = peer, '#' = local clock.
 / .- Source state '*' = current best, '+' = combined, '-' = not combined,
| /             'x' = may be in error, '~' = too variable, '?' = unusable.
||                                                 .- xxxx [ yyyy ] +/- zzzz
||      Reachability register (octal) -.           |  xxxx = adjusted offset,
||      Log2(Polling interval) --.      |          |  yyyy = measured offset,
||                                \     |          |  zzzz = estimated error.
||                                 |    |           \
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^* KA1                           3   6    17    13   +303ns[+6125ns] +/-   69ms

2 核心配置：基础功能调优

2.1 Keepalived 日志分离配置

（独立日志，便于问题排查）

默认情况下。keepalived的日志会被保存在/var/log/messages文件中，这个文件中除了含有keepalived的日志外，还有其他服务的日志信息，这样不利于对于keepalived的日志进行查看

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[root@KA1 ~]# vim /etc/sysconfig/keepalived
KEEPALIVED_OPTIONS="-D -S 6"
[root@KA1 ~]# systemctl restart keepalived.service

[root@KA1 ~]# vim /etc/rsyslog.conf
local6.*                                                /var/log/keepalived.log
[root@KA1 ~]# systemctl restart rsyslog.service


#测试
[root@KA1 ~]# ls -l /var/log/keepalived.log
ls: 无法访问 'keepalived.log': 没有那个文件或目录
[root@KA1 ~]# systemctl restart keepalived.service
[root@KA1 ~]#  ls -l /var/log/keepalived.log
-rw------- 1 root root 3294  1月 28 15:09 /var/log/keepalived.log

2.2 Keepalived 子配置文件拆分

（模块化管理配置）

在主配置文件中如果写入过多的配置不利于对于主配置文件的阅读

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[root@KA1 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
     timinglee_zln@163.com
   }
   notification_email_from timinglee_zln@163.com
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id KA1
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 1
   vrrp_gna_interval 1
   vrrp_mcast_group4 224.0.0.44
}

include /etc/keepalived/conf.d/*.conf			#指定独立子配置文件

[root@KA1 ~]# mkdir  /etc/keepalived/conf.d -p
[root@KA1 ~]# vim /etc/keepalived/conf.d/webvip.conf
vrrp_instance WEB_VIP {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.100/24 dev eth0 label eth0:0
    }
}

[root@KA1 ~]# keepalived -t -f /etc/keepalived/keepalived.conf
[root@KA1 ~]# systemctl restart keepalived.service
[root@KA1 ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.25.254.50  netmask 255.255.255.0  broadcast 172.25.254.255
        inet6 fe80::3901:aeea:786a:7227  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)
        RX packets 17383  bytes 1417554 (1.3 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 32593  bytes 3135052 (2.9 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth0:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
        ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)

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 1000  (Local Loopback)
        RX packets 118  bytes 6828 (6.6 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 118  bytes 6828 (6.6 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


3 核心模式：VRRP 核心机制

  1. 抢占模式（默认机制）

    • 原理：优先级高的节点抢占 VIP

  2. 非抢占模式

    • 原理：持有 VIP 的节点只要存活，不触发 VIP 迁移

    • 适用场景与配置

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      #kA1中
      [root@KA1 ~]# vim /etc/keepalived/keepalived.conf
      vrrp_instance WEB_VIP {
          state BACKUP			#非抢占模式互为backup
          interface eth0
          virtual_router_id 51
          nopreempt				#启动非抢占模式
          priority 100
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
              172.25.254.100/24 dev eth0 label eth0:0
          }
      }

      [root@KA1 ~]# systemctl stop keepalived.service

      #KA2中
      [root@KA2 ~]# vim /etc/keepalived/keepalived.conf
      vrrp_instance WEB_VIP {
          state BACKUP
          interface eth0
          virtual_router_id 51
          nopreempt				#开启非抢占模式
          priority 80
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
              172.25.254.100/24 dev eth0 label eth0:0
          }
      }
      [root@KA2 ~]# systemctl stop keepalived.service

      #测试：
      [root@KA1 ~]# systemctl start keepalived.service
      [root@KA2 ~]# systemctl start keepalived.service

      [root@KA1 ~]# ifconfig
      eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.50  netmask 255.255.255.0  broadcast 172.25.254.255
              inet6 fe80::3901:aeea:786a:7227  prefixlen 64  scopeid 0x20<link>
              ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)
              RX packets 18917  bytes 1546417 (1.4 MiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 34775  bytes 3349412 (3.1 MiB)
              TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

      eth0:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
              ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)

      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 1000  (Local Loopback)
              RX packets 162  bytes 9028 (8.8 KiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 162  bytes 9028 (8.8 KiB)
              TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


      [root@KA1 ~]# systemctl stop keepalived.service

      [root@KA2 ~]# ifconfig
      eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.60  netmask 255.255.255.0  broadcast 172.25.254.255
              inet6 fe80::26df:35e5:539:56bc  prefixlen 64  scopeid 0x20<link>
              ether 00:0c:29:1e:fd:7a  txqueuelen 1000  (Ethernet)
              RX packets 22521  bytes 1553701 (1.4 MiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 18517  bytes 1535122 (1.4 MiB)
              TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

      eth0:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
              ether 00:0c:29:1e:fd:7a  txqueuelen 1000  (Ethernet)

      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 1000  (Local Loopback)
              RX packets 84  bytes 5128 (5.0 KiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 84  bytes 5128 (5.0 KiB)
              TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


      #开启KA1的服务ip不会被抢占到1中
      [root@KA1 ~]# ifconfig
      eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.50  netmask 255.255.255.0  broadcast 172.25.254.255
              inet6 fe80::3901:aeea:786a:7227  prefixlen 64  scopeid 0x20<link>
              ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)
              RX packets 19102  bytes 1561277 (1.4 MiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 35034  bytes 3375682 (3.2 MiB)
              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 1000  (Local Loopback)
              RX packets 162  bytes 9028 (8.8 KiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 162  bytes 9028 (8.8 KiB)
              TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

  3. 延迟抢占模式

    • 原理：避免网络抖动导致的 VIP 频繁切换

    • 配置参数与调优

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      #kA1中
      [root@KA1 ~]# vim /etc/keepalived/keepalived.conf
      vrrp_instance WEB_VIP {
          state BACKUP			#非抢占模式互为backup
          interface eth0
          virtual_router_id 51
          preempt_delay 10				#启动延迟抢占，延迟10s抢占
          priority 100
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
              172.25.254.100/24 dev eth0 label eth0:0
          }
      }

      [root@KA1 ~]# systemctl stop keepalived.service

      #KA2中
      [root@KA2 ~]# vim /etc/keepalived/keepalived.conf
      vrrp_instance WEB_VIP {
          state BACKUP
          interface eth0
          virtual_router_id 51
          preempt_delay 10				#启动延迟抢占，延迟10s抢占
          priority 80
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
              172.25.254.100/24 dev eth0 label eth0:0
          }
      }
      [root@KA2 ~]# systemctl stop keepalived.service

      #测试：
      [root@KA1 ~]# systemctl start keepalived.service
      [root@KA2 ~]# systemctl start keepalived.service

      #在一个独立的shell中开启ip的监控
      [root@KA1 ~]# watch -n 1 ifconfig

      #在KA1另外的shell中关闭keepalived
      [root@KA1 ~]# systemctl stop keepalived.service

      [root@KA1 ~]# systemctl start  keepalived.service
      #操作完毕后观察监控中vip的迁移延迟过程

4 通信模式：单播配置

4.1 单播模式配置步骤与验证

（替代组播，适用于跨网段场景）

为什么要单播，组播模式使用的网址资源最少，但是不能跨网络，如果主备两台主机是跨网络的，那么只能启用单播来实现vrrp通告

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#在KA1中
[root@KA1 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
     timinglee_zln@163.com
   }
   notification_email_from timinglee_zln@163.com
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id KA1
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 1
   vrrp_gna_interval 1
   #vrrp_mcast_group4 224.0.0.44			#关闭组播
}

vrrp_instance WEB_VIP {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    unicast_src_ip 172.25.254.50		#指定单播源地址，通常是本机IP
    unicast_peer {
      172.25.254.60						#指定单播接收地址
    }
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.100/24 dev eth0 label eth0:0
    }
}

#在KA2中
[root@KA2 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
     timinglee_zln@163.com
   }
   notification_email_from timinglee_zln@163.com
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id KA1
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 1
   vrrp_gna_interval 1
   #vrrp_mcast_group4 224.0.0.44			#关闭组播
}

vrrp_instance WEB_VIP {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    unicast_src_ip 172.25.254.60		#指定单播源地址，通常是本机IP
    unicast_peer {
      172.25.254.50						#指定单播接收地址
    }
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.100/24 dev eth0 label eth0:0
    }
}

[root@KA1 ~]# systemctl restart keepalived.service
[root@KA2 ~]# systemctl restart keepalived.service

#测试
#在KA1中开启独立shell监控播报信息
[root@KA1 ~]# tcpdump -i eth0 -nn src host 172.25.254.50 and dst 172.25.254.60

#在KA2中开启独立shell监控播报信息
[root@KA2 ~]# tcpdump -i eth0 -nn src host 172.25.254.60 and dst 172.25.254.50


#在KA1正常时
#ka2播报信息不显示通告内容

[root@KA1 ~]# systemctl stop keepalived.service

#vip会被迁移到KA2,KA2上开始显示播报内容

[root@KA1 ~]# systemctl start keepalived.service

#vip因为优先级被KA1抢占，KA2中播报停止

4.2 Keepalived业务vip迁移告警

(1) 邮件告警环境构建

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#安装邮件软件
[root@KA1 ~]#  dnf install s-nail postfix   -y
[root@KA2 ~]#  dnf install s-nail postfix   -y


#启动邮件代理
[root@KA1 ~]# systemctl start postfix.service
[root@KA2 ~]# systemctl start postfix.service

#设定sendmail可以通过公网邮箱发送邮件下面方式人选其一
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#在Linux主机中配置mailrc（KA1+KA2）
[root@KA1+KA2 ~]# vim /etc/mail.rc
set smtp=smtp.qq.com
set smtp-auth=login
set smtp-auth-user=kaitumei@foxmail.com
set smtp-auth-password=oxsfthfenecmfaae
set from=kaitumei@foxmail.com
set ssl-verify=ignore

#测试邮件
[root@KA1 mail]# echo hello | mailx -s test kaitumei@163.com

[root@KA1 mail]# mailq		#查看邮件队列
Mail queue is empty


[root@KA1 mail]# mail		#查看是否又退信
s-nail version v14.9.22.  Type `?' for help
/var/spool/mail/root: 1 message
▸   1 Mail Delivery Subsys  2026-01-28 16:26   69/2210  "Returned mail: see transcript for details  "
&q 退出


#查看对应邮箱是否有邮件收到

(2) 设定keepalived告警脚本

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[root@KA1 ~]# mkdir  -p /etc/keepalived/scripts
[root@KA2 ~]#  mkdir  -p /etc/keepalived/scripts

#编写告警脚本
[root@KA1+2 ~]#  vim /etc/keepalived/scripts/waring.sh
#!/bin/bash
mail_dest='kaitumei@163.com'

mail_send()
{
    mail_subj="$HOSTNAME to be $1 vip 转移"
    mail_mess="`date +%F\ %T`: vrrp 转移,$HOSTNAME 变为 $1"
    echo "$mail_mess" | mail -s "$mail_subj" $mail_dest
}
case $1 in
    master)
    mail_send master
    ;;
    backup)
    mail_send backup
    ;;
    fault)
    mail_send fault
    ;;
    *)
    exit 1
    ;;
esac


[root@KA1+2 ~]# chmod  +x /etc/keepalived/scripts/waring.sh

[root@KA1 ~]# /etc/keepalived/scripts/waring.sh master

#对应邮箱中会出现邮件

(3) 配置keepalived告警

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#在KA1和KA2中设定配置文件
! Configuration File for keepalived

global_defs {
   notification_email {
     timinglee_zln@163.com
   }
   notification_email_from timinglee_zln@163.com
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id KA1
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 1
   vrrp_gna_interval 1
   vrrp_mcast_group4 224.0.0.44
   enable_script_security
   script_user root
}
vrrp_instance WEB_VIP {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
  # unicast_src_ip 172.25.254.50
  # unicast_peer {
  #   172.25.254.60
#   }
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.100/24 dev eth0 label eth0:0
    }
    notify_master "/etc/keepalived/scripts/waring.sh master"
    notify_backup "/etc/keepalived/scripts/waring.sh backup"
    notify_fault "/etc/keepalived/scripts/waring.sh fault"
}


[root@KA1+2 ~]# systemctl restart keepalived.service



#测试
[root@KA1 ~]# systemctl stop keepalived.service		#停止服务后查看邮件
[root@KA1 ~]# systemctl start keepalived.service	#开启服务后查看邮件

5 架构进阶：双主模式

  1. 双主模式核心原理（两个节点各持有独立 VIP，互为主备）

  2. 双主模式代理不同业务（实现多业务高可用）

    • 实验环境准备

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      #在KA1中
      [root@KA1 ~]# vim /etc/keepalived/keepalived.conf
      vrrp_instance WEB_VIP {						#第一个虚拟路由，以master身份设定
          state MASTER
          interface eth0
          virtual_router_id 51
          priority 100
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
              172.25.254.100/24 dev eth0 label eth0:0
          }
      }

      vrrp_instance DB_VIP {				#第二个虚拟路由。以backup身份设定
          state BACKUP
          interface eth0
          virtual_router_id 52
          priority 80
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
              172.25.254.200/24 dev eth0 label eth0:1
          }
      }


      #KA2中
      [root@KA2 ~]# vim /etc/keepalived/keepalived.conf
      vrrp_instance WEB_VIP {
          state BACKUP
          interface eth0
          virtual_router_id 51
          preempt_delay 10
          priority 80
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
            172.25.254.100/24 dev eth0 label eth0:0
          }
      }
      vrrp_instance DB_VIP {
          state MASTER
          interface eth0
          virtual_router_id 52
          preempt_delay 10
          priority 100
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
            172.25.254.200/24 dev eth0 label eth0:1
          }
      }
      [root@KA1 ~]# systemctl restart keepalived.service
      [root@KA2 ~]# systemctl restart keepalived.service


      #测试
      [root@KA1 ~]# ifconfig
      eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.50  netmask 255.255.255.0  broadcast 172.25.254.255
              inet6 fe80::3901:aeea:786a:7227  prefixlen 64  scopeid 0x20<link>
              ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)
              RX packets 38766  bytes 3548249 (3.3 MiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 67456  bytes 6209788 (5.9 MiB)
              TX errors 0  dropped 2 overruns 0  carrier 0  collisions 0

      eth0:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
              ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)

      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 1000  (Local Loopback)
              RX packets 782  bytes 60465 (59.0 KiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 782  bytes 60465 (59.0 KiB)
              TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


      [root@KA2 ~]# ifconfig
      eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.60  netmask 255.255.255.0  broadcast 172.25.254.255
              inet6 fe80::26df:35e5:539:56bc  prefixlen 64  scopeid 0x20<link>
              ether 00:0c:29:1e:fd:7a  txqueuelen 1000  (Ethernet)
              RX packets 46164  bytes 3559703 (3.3 MiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 38170  bytes 3306899 (3.1 MiB)
              TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

      eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.200  netmask 255.255.255.0  broadcast 0.0.0.0
              ether 00:0c:29:1e:fd:7a  txqueuelen 1000  (Ethernet)

      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 1000  (Local Loopback)
              RX packets 532  bytes 39588 (38.6 KiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 532  bytes 39588 (38.6 KiB)
              TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0


      [root@KA1 ~]# systemctl stop keepalived.service
      [root@KA2 ~]# ifconfig
      eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.60  netmask 255.255.255.0  broadcast 172.25.254.255
              inet6 fe80::26df:35e5:539:56bc  prefixlen 64  scopeid 0x20<link>
              ether 00:0c:29:1e:fd:7a  txqueuelen 1000  (Ethernet)
              RX packets 46204  bytes 3562823 (3.3 MiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 38240  bytes 3313319 (3.1 MiB)
              TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

      eth0:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
              ether 00:0c:29:1e:fd:7a  txqueuelen 1000  (Ethernet)

      eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.200  netmask 255.255.255.0  broadcast 0.0.0.0
              ether 00:0c:29:1e:fd:7a  txqueuelen 1000  (Ethernet)


      [root@KA2 ~]# systemctl stop keepalived.service
      [root@KA1 ~]# ifconfig
      eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.50  netmask 255.255.255.0  broadcast 172.25.254.255
              inet6 fe80::3901:aeea:786a:7227  prefixlen 64  scopeid 0x20<link>
              ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)
              RX packets 39277  bytes 3653121 (3.4 MiB)
              RX errors 0  dropped 0  overruns 0  frame 0
              TX packets 67902  bytes 6264989 (5.9 MiB)
              TX errors 0  dropped 2 overruns 0  carrier 0  collisions 0

      eth0:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
              ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)

      eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
              inet 172.25.254.200  netmask 255.255.255.0  broadcast 0.0.0.0
              ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)

    • 不同 VIP 绑定不同业务的配置

      • 实验环境

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        #web服务设定再个实验已经设定完成
        #在rs中设定lo添加vip2 172.25.254.200、32
        #在rs中搭建数据库
        [root@rs1+2 ~]# dnf install mariadb-server -y
        [root@rs1+2 ~]# systemctl enable --now mariadb
        [root@rs1+2 ~]# mysql
        Welcome to the MariaDB monitor.  Commands end with ; or \g.
        Your MariaDB connection id is 3
        Server version: 10.5.27-MariaDB MariaDB Server

        Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

        Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

        MariaDB [(none)]> CREATE USER 'hua'@'%' identified by 'hua';
        Query OK, 0 rows affected (0.001 sec)

        MariaDB [(none)]> GRANT ALL ON *.* TO 'hua'@'%';
        Query OK, 0 rows affected (0.001 sec)

        #测试
        [root@rs1 ~]# mysql -uhua -phua -h172.25.254.10
        Welcome to the MariaDB monitor.  Commands end with ; or \g.
        Your MariaDB connection id is 4
        Server version: 10.5.27-MariaDB MariaDB Server

        Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

        Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

        MariaDB [(none)]> quit

        [root@rs1 ~]# mysql -ulee -plee -h172.25.254.20
        Welcome to the MariaDB monitor.  Commands end with ; or \g.
        Your MariaDB connection id is 4
        Server version: 10.5.27-MariaDB MariaDB Server

        Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

        Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

        MariaDB [(none)]> quit

      • 实现不同vip代理不同业务

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        #KA1和KA2
        [root@KA1+2 ~]# vim /etc/keepalived/keepalived.conf
        include /etc/keepalived/conf.d/webserver.conf
        include /etc/keepalived/conf.d/datebase.conf

        [root@KA1+2 ~]# vim /etc/keepalived/conf.d/webserver.conf
        virtual_server 172.25.254.100 80 {
            delay_loop 6
            lb_algo rr
            lb_kind DR
            protocol TCP

            real_server 172.25.254.10 80 {
                weight 1
                HTTP_GET {
                    url {
                      path /
                      status_code 200
                    }
                    connect_timeout 1
                    retry 3
                    delay_before_retry 1
              }
            }

            real_server 172.25.254.20 80 {
                weight 1
                TCP_CHECK {
                  connect_timeout 5
                  retry 3
                  delay_before_retry 3
                  connect_port 80
              }
            }
        }
        [root@KA1 ~]# vim /etc/keepalived/conf.d/datebase.conf
        virtual_server 172.25.254.200 3306 {
            delay_loop 6
            lb_algo rr
            lb_kind DR
            protocol TCP

            real_server 172.25.254.10 3306 {
                weight 1
                TCP_CHECK {
                  connect_timeout 5
                  retry 3
                  delay_before_retry 3
                  connect_port 3306
              }
            }

            real_server 172.25.254.20 3306 {
                weight 1
                TCP_CHECK {
                  connect_timeout 5
                  retry 3
                  delay_before_retry 3
                  connect_port 3306
              }
            }
        }

        [root@KA1+2 ~]# systemctl restart keepalived.service


        [root@rs1+2 ~]# vim /etc/NetworkManager/system-connections/lo.nmconnection
        address3=172.25.254.200/32
        [root@rs1 ~]# nmcli connection reload
        [root@rs1 ~]# nmcli connection up lo

    • 业务可用性测试（故障模拟与恢复验证）

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    [root@rs2 ~]# mysql -uhua  -phua  -h172.25.254.200
    Welcome to the MariaDB monitor.  Commands end with ; or \g.
    Your MariaDB connection id is 89
    Server version: 10.5.27-MariaDB MariaDB Server

    Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

    Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

    MariaDB [(none)]>



    [Administrator.DESKTOP-VJ307M3] ➤ curl 172.25.254.100
    RS1 - 172.25.254.10
                                                                                                        ✔
    ─────────────────────────────────────────────────────────────────────────────────────────────────────
    [2026-01-29 11:58.55]  ~
    [Administrator.DESKTOP-VJ307M3] ➤ curl 172.25.254.100
    RS2 - 172.25.254.20

6 实战进阶：全栈高可用方案

  1. VRRP Script 环境准备

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    #在KA1和KA2中安装haproxy
    [root@KA1+2 ~]# dnf install haproxy-2.4.22-4.el9.x86_64  -y

    [root@KA1+2 ~]# vim /etc/sysctl.conf
    net.ipv4.ip_nonlocal_bind=1

    [root@KA1+2 ~]# vim /etc/haproxy/haproxy.cfg
    listen webserver
        bind 172.25.254.100:80
        mode http
        server web1 172.25.254.10:80 check
        server web2 172.25.254.20:80 check
        
    [root@KA1+2 ~]# systemctl enable --now haproxy.service

  2. VRRP Script 实战案例

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    #在KA1主机中
    [root@KA1 ~]# vim /etc/keepalived/scripts/test.sh
    #!/bin/bash
    [ ! -f "/mnt/lee" ]

    [root@KA1 ~]# vim /etc/keepalived/keepalived.conf
    ! Configuration File for keepalived

    global_defs {
       notification_email {
         acassen@firewall.loc
         failover@firewall.loc
         sysadmin@firewall.loc
       }
       notification_email_from Alexandre.Cassen@firewall.loc
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id KA1
       vrrp_skip_check_adv_addr
       #vrrp_strict
       vrrp_garp_interval 1
       vrrp_gna_interval 1
       vrrp_mcast_group4 224.0.0.44
    }

    vrrp_script check_lee {
        script "/etc/keepalived/scripts/test.sh"
        interval 1
        weight -30
        fall 2
        rise 2
        timeout 2
        user root
    }

    vrrp_instance WEB_VIP {
        state MASTER
        interface eth0
        virtual_router_id 51
        priority 100
        advert_int 1
        nopreempt no
        authentication {
            auth_type PASS
            auth_pass 1111
        }
        virtual_ipaddress {
            172.25.254.100/24 dev eth0 label eth0:0
        }
        track_script {
            check_lee
        }
    }

    [root@KA2 ~]# vim /etc/keepalived/keepalived.conf
    ! Configuration File for keepalived

    global_defs {
       notification_email {
         timinglee_zln@163.com
       }
       notification_email_from timinglee_zln@163.com
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id KA2
       vrrp_skip_check_adv_addr
       #vrrp_strict
       vrrp_garp_interval 1
       vrrp_gna_interval 1
       vrrp_mcast_group4 224.0.0.44
    }

    vrrp_script check_lee {
        script "/etc/keepalived/scripts/test.sh"
        interval 1
        weight -30
        fall 2
        rise 2
        timeout 2
        user root
    }


    vrrp_instance WEB_VIP {
        state BACKUP
        interface eth0
        virtual_router_id 51
        priority 80
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 1111
        }
        virtual_ipaddress {
            172.25.254.100/24 dev eth0 label eth0:0
        }
        track_script {
            check_lee
        }
    }




    [root@KA1 ~]# systemctl restart keepalived.service


    #测试：
    [root@KA1 ~]# ifconfig
    eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 172.25.254.50  netmask 255.255.255.0  broadcast 172.25.254.255
            inet6 fe80::3901:aeea:786a:7227  prefixlen 64  scopeid 0x20<link>
            ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)
            RX packets 98198  bytes 9235557 (8.8 MiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 145101  bytes 12247386 (11.6 MiB)
            TX errors 0  dropped 9 overruns 0  carrier 0  collisions 0

    eth0:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
            ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)

    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 1000  (Local Loopback)
            RX packets 932  bytes 72195 (70.5 KiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 932  bytes 72195 (70.5 KiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

    [root@KA1 ~]# touch /mnt/lee

    [root@KA1 ~]# ifconfig
    eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 172.25.254.50  netmask 255.255.255.0  broadcast 172.25.254.255
            inet6 fe80::3901:aeea:786a:7227  prefixlen 64  scopeid 0x20<link>
            ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)
            RX packets 97968  bytes 9216259 (8.7 MiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 144858  bytes 12219108 (11.6 MiB)
            TX errors 0  dropped 9 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 1000  (Local Loopback)
            RX packets 932  bytes 72195 (70.5 KiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 932  bytes 72195 (70.5 KiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

    [root@KA1 ~]# rm -fr /mnt/lee

    [root@KA1 ~]# ifconfig
    eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 172.25.254.50  netmask 255.255.255.0  broadcast 172.25.254.255
            inet6 fe80::3901:aeea:786a:7227  prefixlen 64  scopeid 0x20<link>
            ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)
            RX packets 98198  bytes 9235557 (8.8 MiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 145101  bytes 12247386 (11.6 MiB)
            TX errors 0  dropped 9 overruns 0  carrier 0  collisions 0

    eth0:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
            ether 00:0c:29:26:33:d9  txqueuelen 1000  (Ethernet)

    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 1000  (Local Loopback)
            RX packets 932  bytes 72195 (70.5 KiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 932  bytes 72195 (70.5 KiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

  3. Keepalived + Haproxy 整合（实现负载均衡 + 高可用）

    • 整合配置步骤

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      [root@KA1 ~]# vim /etc/keepalived/scripts/haproxy_check.sh
      #!/bin/bash
      killall -0 haproxy &> /dev/null

      [root@KA1 ~]# chmod +x /etc/keepalived/scripts/haproxy_check.sh
      [root@KA1 ~]# vim /etc/keepalived/keepalived.conf
      vrrp_script haporxy_check {
          script "/etc/keepalived/scripts/haproxy_check.sh"
          interval 1
          weight -30
          fall 2
          rise 2
          timeout 2
          user root
      }
      vrrp_instance WEB_VIP {
          state MASTER
          interface eth0
          virtual_router_id 51
          priority 100
          advert_int 1
          authentication {
              auth_type PASS
              auth_pass 1111
          }
          virtual_ipaddress {
              172.25.254.100/24 dev eth0 label eth0:0
          }
          track_script {
              haporxy_check
          }
      }

      [root@KA1 ~]# systemctl restart keepalived.service


      #测试
      通过关闭和开启haproxy来观察vip是否迁移

    • 全链路可用性测试