Nginx VPS配置：反向代理和负载均衡指南

在Ubuntu/Debian VPS上安装最新版Nginx：

apt update
apt install -y nginx

systemctl enable nginx
systemctl start nginx
nginx -v

# 开放防火墙端口
ufw allow 'Nginx Full'
ufw enable

Nginx主配置文件（/etc/nginx/nginx.conf）的核心参数调优：

user www-data;
worker_processes auto;  # 自动匹配CPU核心数
worker_rlimit_nofile 65535;

events {
    worker_connections 4096;  # 每worker最大连接数
    use epoll;                # Linux高效I/O模型
    multi_accept on;
}

http {
    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    keepalive_requests 1000;
    types_hash_max_size 2048;

    # 安全头
    server_tokens off;  # 隐藏Nginx版本号

    include /etc/nginx/mime.types;
    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

Nginx反向代理将外部请求转发到后端应用服务器，是生产环境中隔离应用层和网络层的标准方案：

server {
    listen 443 ssl http2;
    server_name api.yourdomain.com;

    ssl_certificate /etc/letsencrypt/live/api.yourdomain.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/api.yourdomain.com/privkey.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256;

    # 安全响应头
    add_header X-Frame-Options "SAMEORIGIN";
    add_header X-Content-Type-Options "nosniff";
    add_header X-XSS-Protection "1; mode=block";
    add_header Strict-Transport-Security "max-age=31536000" always;

    location / {
        proxy_pass http://127.0.0.1:4000;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        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;
        proxy_read_timeout 90;
        proxy_buffering off;
    }
}

Nginx的负载均衡功能可以将流量分发到多个后端服务器或进程，提升整体吞吐量和高可用性：

# 在http块中定义upstream组
upstream backend_pool {
    # 轮询（默认，平均分配请求）
    server 127.0.0.1:3001;
    server 127.0.0.1:3002;
    server 127.0.0.1:3003;

    # IP哈希（同一客户端IP始终访问同一后端）
    # ip_hash;

    # 最少连接（优先分配给空闲后端）
    # least_conn;

    keepalive 32;  # 保持与后端的长连接
}

server {
    listen 80;
    server_name yourdomain.com;

    location / {
        proxy_pass http://backend_pool;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_http_version 1.1;
        proxy_set_header Connection "";  # 启用HTTP/1.1长连接
    }
}

在单台VPS上，可以将PM2多进程（cluster模式）与Nginx负载均衡结合，充分利用多核CPU。

配置Nginx代理缓存可以大幅减少后端应用的负载，显著提升响应速度：

# 在http块中定义缓存区域
proxy_cache_path /var/cache/nginx levels=1:2 keys_zone=app_cache:10m max_size=1g inactive=60m;

server {
    listen 80;
    server_name yourdomain.com;

    location / {
        proxy_pass http://127.0.0.1:3000;
        proxy_cache app_cache;
        proxy_cache_valid 200 10m;      # 200响应缓存10分钟
        proxy_cache_valid 404 1m;       # 404缓存1分钟
        proxy_cache_use_stale error timeout updating;
        add_header X-Cache-Status $upstream_cache_status;
    }

    # 静态文件直接服务（绕过后端）
    location /static/ {
        root /var/www/myapp;
        expires 1y;
        add_header Cache-Control "public, immutable";
        gzip_static on;
    }
}

开启Nginx的Gzip压缩：

gzip on;
gzip_comp_level 5;
gzip_min_length 256;
gzip_types text/plain text/css application/json application/javascript
           text/xml application/xml image/svg+xml;
gzip_vary on;

在Anubiz Host的NVMe VPS上，Nginx的静态文件服务性能接近理论I/O上限，是高性能Web托管的理想组合。