# Keepalived+Nginx实现高可用

# 环境准备

操作系统：Ubuntu 24.04 LTS Nginx服务器A: 192.168.0.141 （master） Nginx服务器B: 192.168.0.142 （bakcup）

# 安装依赖

在安装 Keepalived 之前，确保系统上安装了必要的开发工具和库。通常需要以下依赖

sudo apt update
sudo apt install build-essential libssl-dev libnl-3-dev libnl-genl-3-dev libnl-route-3-dev

# 源码安装keepalived

仅在其中一台服务器上操作即可，如：Nginx服务器A

# 下载源码包

从 Keepalived 的官方网站或 GitHub 仓库下载最新版本的源码包下载地址：https://www.keepalived.org/download.html

# 安装

将源码包 keepalived-2.3.2.tar.gz 上传至服务器192.168.0.141，并解压

tar -zvxf keepalived-2.3.2.tar.gz

编译和安装

cd keepalived-2.2.7

./configure --prefix=/usr/local/keepalived
make
sudo make install

# 配置keepalived

同样在Nginx服务器A上操作

# 配置systemd服务

安装完成后，会在源码包目录生成systemd服务文件 keepalived-2.3.2/keepalived/keepalived.service

# 复制服务文件到 /usr/lib/systemd/system/ 下，并重新加载配置
cp keepalived-2.3.2/keepalived/keepalived.service /usr/lib/systemd/system/
systemctl daemon-reload

# 创建健康检查脚本

创建一个脚本，用于通过 HTTP 请求检查 Nginx 的健康状态。假设 Nginx 在本地主机上运行，并且可以通过 http://localhost/seeyon/main.do 访问健康检查页面

vim /usr/local/keepalived/scripts/check_nginx.sh

#!/bin/bash

curl -sfI --connect-timeout 5 --max-time 15 http://localhost/seeyon/main.do || exit 1

# 修改keepalived配置

vim /usr/local/keepalived/etc/keepalived/keepalived.conf

global_defs {
   router_id nginxA  # keepalived节点唯一标识，可以修改为主机名或自定义
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_script check_nginx {
    script "/usr/local/keepalived/scripts/check_nginx.sh"
    interval 2  # 每2秒检查一次
    weight -5   # 如果检查失败，减少5个优先级
}

vrrp_instance Nginx_HA {  # vrrp实例名，可自定义
    state MASTER   # 设置初始vrrp实例角色为master
    interface ens33  # 绑定的网卡名称，请根据实际网卡名修改
    virtual_router_id 51  # 虚拟路由ID标识，范围0-255，同一实例中master与backup必须一致
    priority 100  # 优先级，范围1-254，数字越大优先级越高；同一实例中master优先级高于backup
    advert_int 1  # 主备之间同步检查时间间隔，单位：秒
    authentication {
        auth_type PASS
        auth_pass Seeyon@123   # 自定义认证密码
    }
    virtual_ipaddress {
        192.168.0.140  # 指定VIP
    }
    track_script {
        check_nginx
    }
}

# 启动&检查

systemctl start keepalived
systemctl status keepalived

服务器启动成功后可以看到ens33网卡上新绑定了一个vip: 192.168.0.140

# 配置其他节点

将NginxA服务器上的 /usr/local/keepalived 和 /usr/lib/systemd/system/keepalived.service 拷贝到NginxB服务器

# 如果没有安装rsync可以用 scp -r /usr/local/keepalived root@192.168.0.142:/usr/local/
rsync -av /usr/local/keepalived root@192.168.0.142:/usr/local/
rsync -av /usr/lib/systemd/system/keepalived.service root@192.168.0.142:/usr/lib/systemd/system/

连接NginxB服务器，修改配置文件

vim /usr/local/keepalived/etc/keepalived/keepalived.conf

global_defs {
   router_id nginxB  # keepalived节点唯一标识，可以修改为主机名或自定义
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_script check_nginx {
    script "/usr/local/keepalived/scripts/check_nginx.sh"
    interval 2  # 每2秒检查一次
    weight -5   # 如果检查失败，减少5个优先级
}

vrrp_instance Nginx_HA {  # vrrp实例名，可自定义
    state BACKUP   # 设置初始vrrp实例角色为master
    interface ens33  # 绑定的网卡名称，请根据实际网卡名修改
    virtual_router_id 51  # 虚拟路由ID标识，范围0-255，同一实例中master与backup必须一致
    priority 99  # 优先级，范围1-254，数字越大优先级越高；同一实例中master优先级高于backup
    advert_int 1  # 主备之间同步检查时间间隔，单位：秒
    authentication {
        auth_type PASS
        auth_pass Seeyon@123   # 自定义认证密码
    }
    virtual_ipaddress {
        192.168.0.140  # 指定VIP
    }
    track_script {
        check_nginx
    }
}

# 重载配置文件并启动keepalived，确认服务已经成功启动
systemctl daemon-reload
systemctl start keepalived
systemctl status keepalived

编撰人：wangyxyf

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Keepalived+Nginx实现高可用

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