Linux系统下Keepalived的安装与配置全攻略

一、Keepalived简介与工作原理

Keepalived是基于VRRP协议实现的高可用解决方案，通过虚拟IP(VIP)漂移技术确保服务不间断。其核心组件包括：

• VRRP Stack - 负责主备节点状态维护
• Health Checking - 服务健康状态检测
• SMTP通知 - 故障报警机制

二、安装前准备

1. 环境要求

# 系统版本检查
cat /etc/redhat-release  # CentOS/RHEL
lsb_release -a            # Ubuntu/Debian

2. 依赖安装

# CentOS/RHEL
yum install -y gcc openssl-devel popt-devel ipvsadm

# Ubuntu/Debian
apt-get install -y build-essential libssl-dev libpopt-dev ipvsadm

三、Keepalived安装步骤

方法1：通过包管理器安装

# CentOS/RHEL
yum install -y keepalived

# Ubuntu/Debian
apt-get install -y keepalived

方法2：源码编译安装（推荐获取最新版本）

wget http://www.keepalived.org/software/keepalived-2.2.4.tar.gz
tar zxvf keepalived-*.tar.gz
cd keepalived-2.2.4
./configure --prefix=/usr/local/keepalived
make && make install

四、详细配置指南

1. 主节点配置示例

vim /etc/keepalived/keepalived.conf

global_defs {
    router_id LVS_MASTER  # 唯一标识
}

vrrp_instance VI_1 {
    state MASTER          # 主节点
    interface eth0        # 监听的网卡
    virtual_router_id 51  # 虚拟路由ID(0-255)
    priority 100          # 优先级(主>备)
    advert_int 1          # 检测间隔(秒)
    
    authentication {
        auth_type PASS
        auth_pass 1111    # 认证密码
    }
    
    virtual_ipaddress {
        192.168.1.100/24  # 虚拟IP
    }
}

2. 备节点配置差异

• 修改state BACKUP
• 降低priority 90
• 保持其他参数完全一致

五、高级配置技巧

1. 服务健康检测

vrrp_script chk_nginx {
    script "/usr/bin/killall -0 nginx" # 检测nginx进程
    interval 2                         # 每2秒检测一次
    weight -20                         # 失败时优先级降低20
}

track_script {
    chk_nginx  # 引用检测脚本
}

2. 邮件报警配置

global_defs {
    notification_email {
        [email protected]
    }
    notification_email_from keepalived@localhost
    smtp_server 127.0.0.1
    smtp_connect_timeout 30
}

六、服务管理与故障排查

1. 服务控制命令

systemctl start keepalived    # 启动服务
systemctl status keepalived   # 查看状态
journalctl -u keepalived -f   # 实时日志

2. 常见问题解决