Nginx反向代理负载均衡配置指南

Nginx是一个高性能的HTTP和反向代理服务器，可以轻松实现负载均衡功能。以下是配置Nginx作为反向代理负载均衡器的详细步骤。

基本配置步骤

1. 安装Nginx

确保已安装Nginx，如果没有安装可以使用以下命令：

# Ubuntu/Debian
sudo apt update
sudo apt install nginx

# CentOS/RHEL
sudo yum install epel-release
sudo yum install nginx

2. 配置上游服务器(upstream)

在Nginx配置文件中(通常在/etc/nginx/nginx.conf或/etc/nginx/conf.d/default.conf)，添加upstream模块定义后端服务器组：

http {
    upstream backend {
        # 定义后端服务器列表
        server backend1.example.com weight=5;
        server backend2.example.com;
        server backend3.example.com;
        server backup.example.com backup;
    }

    # 其他配置...
}

3. 配置server块实现反向代理

server {
    listen 80;
    server_name yourdomain.com;

    location / {
        proxy_pass http://backend;  # 这里的backend对应upstream名称
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}

负载均衡策略

Nginx支持多种负载均衡算法：

1. 轮询(默认)

upstream backend {
    server backend1.example.com;
    server backend2.example.com;
}

2. 加权轮询

upstream backend {
    server backend1.example.com weight=3;
    server backend2.example.com weight=2;
}

3. IP哈希(保持会话)

upstream backend {
    ip_hash;
    server backend1.example.com;
    server backend2.example.com;
}

4. 最少连接

upstream backend {
    least_conn;
    server backend1.example.com;
    server backend2.example.com;
}

高级配置选项

健康检查

upstream backend {
    server backend1.example.com max_fails=3 fail_timeout=30s;
    server backend2.example.com max_fails=3 fail_timeout=30s;
}

长连接保持

upstream backend {
    server backend1.example.com;
    server backend2.example.com;
    keepalive 32;
}

HTTPS后端

upstream backend {
    server backend1.example.com:443;
    server backend2.example.com:443;
}

server {
    location / {
        proxy_pass https://backend;
        proxy_ssl_verify on;
        proxy_ssl_trusted_certificate /path/to/ca.crt;
    }
}

完整示例配置

http {
    upstream backend {
        least_conn;
        server 192.168.1.100:8080 weight=3 max_fails=2 fail_timeout=30s;
        server 192.168.1.101:8080 weight=2 max_fails=2 fail_timeout=30s;
        server 192.168.1.102:8080 backup;
        keepalive 32;
    }

    server {
        listen 80;
        server_name example.com;

        location / {
            proxy_pass http://backend;
            proxy_http_version 1.1;
            proxy_set_header Connection "";
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;

            # 超时设置
            proxy_connect_timeout 5s;
            proxy_read_timeout 60s;
            proxy_send_timeout 30s;
        }
    }
}

配置验证与重载

1. 检查配置语法：

sudo nginx -t

2. 重载Nginx配置：

sudo systemctl reload nginx
# 或
sudo service nginx reload

监控与调优

1. 启用状态页面：

server {
    listen 8080;
    server_name localhost;

    location /nginx_status {
        stub_status on;
        access_log off;
        allow 127.0.0.1;
        deny all;
    }
}

2. 性能调优参数：

- worker_processes: 设置为CPU核心数 - worker_connections: 每个worker的最大连接数 - keepalive_timeout: 保持连接的超时时间

通过以上配置，您可以实现一个高性能的Nginx反向代理负载均衡系统，根据实际需求调整负载均衡策略和参数。