打造零故障架构：基于 Keepalived 的 Nginx 和 HAProxy 高可用实战指南

        ┌──────────────┐
        │   Client     │
        └──────┬───────┘
               │
         VIP: 192.168.1.100
               │
    ┌──────────┴──────────┐
    │                     │
┌───▼───┐           ┌─────▼────┐
│ Nginx │           │ HAProxy  │
│ Master│           │ Backup   │
└───┬───┘           └─────┬────┘
    │                     │
    └──────────┬──────────┘
               │
         ┌─────▼─────┐
         │  Backend  │
         └───────────┘

yum install -y keepalived

apt-get update && apt-get install -y keepalived

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.1.100/24
    }
    track_script {
        chk_nginx
    }
}
​
vrrp_script chk_nginx {
    script "/etc/keepalived/check_nginx.sh"
    interval 2
    weight -20
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 123456
    }
    virtual_ipaddress {
        192.168.1.100/24
    }
    track_script {
        chk_nginx
    }
}
​
vrrp_script chk_nginx {
    script "/etc/keepalived/check_nginx.sh"
    interval 2
    weight -20
}

vi /etc/keepalived/check_nginx.sh
把以下内容填入

#!/bin/bash
if ! pgrep nginx > /dev/null; then
    systemctl start nginx
    sleep 2
    if ! pgrep nginx > /dev/null; then
        exit 1
    fi
fi
exit 0

chmod +x /etc/keepalived/check_nginx.sh

systemctl enable keepalived --now

ip addr show eth0

systemctl stop nginx

#!/bin/bash
if ! pgrep haproxy > /dev/null; then
    systemctl start haproxy
    sleep 2
    if ! pgrep haproxy > /dev/null; then
        exit 1
    fi
fi
exit 0