Nginx設定例：リバースプロキシ、SSL、静的サイト

Nginx の基本

Nginx（「エンジンエックス」と発音）は高性能なHTTPサーバー、リバースプロキシ、ロードバランサーです。イベント駆動アーキテクチャにより少ないメモリで数千の同時接続を処理します。メイン設定ファイルは通常 /etc/nginx/nginx.conf にあります。

# Main configuration file structure
# /etc/nginx/nginx.conf

user nginx;
worker_processes auto;          # One worker per CPU core
error_log /var/log/nginx/error.log warn;
pid /run/nginx.pid;

events {
    worker_connections 1024;    # Max connections per worker
    multi_accept on;            # Accept multiple connections at once
}

http {
    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    # Logging format
    log_format main '$remote_addr - $remote_user [$time_local] '
                    '"$request" $status $body_bytes_sent '
                    '"$http_referer" "$http_user_agent"';

    access_log /var/log/nginx/access.log main;

    sendfile on;                # Efficient file transfer
    tcp_nopush on;              # Optimize TCP packets
    tcp_nodelay on;             # Disable Nagle's algorithm
    keepalive_timeout 65;       # Keep connections alive
    types_hash_max_size 2048;

    # Include site configurations
    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

静的サイト設定

最もシンプルで一般的な用途：ディスクからHTML、CSS、JavaScript、画像ファイルを直接配信します。

# Static website configuration
# /etc/nginx/conf.d/static-site.conf

server {
    listen 80;
    listen [::]:80;
    server_name example.com www.example.com;

    # Document root
    root /var/www/example.com/html;
    index index.html index.htm;

    # Main location block
    location / {
        try_files $uri $uri/ =404;
    }

    # Cache static assets aggressively
    location ~* \.(css|js|jpg|jpeg|png|gif|ico|svg|woff|woff2|ttf|eot)$ {
        expires 30d;
        add_header Cache-Control "public, immutable";
        access_log off;
    }

    # Cache HTML files with shorter duration
    location ~* \.html$ {
        expires 1h;
        add_header Cache-Control "public, must-revalidate";
    }

    # Deny access to hidden files (.htaccess, .git, etc.)
    location ~ /\. {
        deny all;
        access_log off;
        log_not_found off;
    }

    # Custom error pages
    error_page 404 /404.html;
    error_page 500 502 503 504 /50x.html;
    location = /50x.html {
        root /usr/share/nginx/html;
    }

    access_log /var/log/nginx/example.com.access.log;
    error_log /var/log/nginx/example.com.error.log;
}

リバースプロキシ設定

リバースプロキシはクライアントとバックエンドアプリケーション（Node.js、Python、Goなど）の間に位置し、リクエストを転送してレスポンスを返します。

# Reverse proxy to Node.js/Python/Go application
# /etc/nginx/conf.d/app-proxy.conf

server {
    listen 80;
    server_name app.example.com;

    # Max upload size
    client_max_body_size 50M;

    # Proxy all requests to the backend application
    location / {
        proxy_pass http://127.0.0.1:3000;

        # Pass the real client IP to the backend
        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;

        # WebSocket support (for Socket.IO, etc.)
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";

        # Timeouts
        proxy_connect_timeout 60s;
        proxy_send_timeout 60s;
        proxy_read_timeout 60s;

        # Buffering settings
        proxy_buffering on;
        proxy_buffer_size 4k;
        proxy_buffers 8 4k;
    }

    # Serve static files directly (bypass the backend)
    location /static/ {
        alias /var/www/app/static/;
        expires 30d;
        add_header Cache-Control "public, immutable";
    }

    # Health check endpoint
    location /health {
        proxy_pass http://127.0.0.1:3000/health;
        access_log off;
    }

    access_log /var/log/nginx/app.access.log;
    error_log /var/log/nginx/app.error.log;
}

SSL/TLS 設定

HTTPSでサイトを保護することは現代のWeb開発では必須です。この設定はLet's Encrypt証明書を使用し、強力な暗号スイートとHSTSを含むTLSセキュリティのベストプラクティスに従います。

# SSL/TLS configuration with Let's Encrypt
# /etc/nginx/conf.d/ssl-site.conf

# Redirect all HTTP traffic to HTTPS
server {
    listen 80;
    listen [::]:80;
    server_name example.com www.example.com;

    # Let's Encrypt ACME challenge
    location /.well-known/acme-challenge/ {
        root /var/www/certbot;
    }

    # 301 permanent redirect to HTTPS
    location / {
        return 301 https://$server_name$request_uri;
    }
}

# HTTPS server block
server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name example.com www.example.com;

    # Let's Encrypt certificate paths
    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;

    # SSL session settings
    ssl_session_timeout 1d;
    ssl_session_cache shared:SSL:50m;
    ssl_session_tickets off;

    # Modern TLS configuration (TLS 1.2 + 1.3 only)
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
    ssl_prefer_server_ciphers off;

    # OCSP Stapling (faster certificate verification)
    ssl_stapling on;
    ssl_stapling_verify on;
    ssl_trusted_certificate /etc/letsencrypt/live/example.com/chain.pem;
    resolver 8.8.8.8 8.8.4.4 valid=300s;
    resolver_timeout 5s;

    # HSTS (force HTTPS for 2 years, including subdomains)
    add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;

    root /var/www/example.com/html;
    index index.html;

    location / {
        try_files $uri $uri/ =404;
    }

    access_log /var/log/nginx/example.com.ssl.access.log;
    error_log /var/log/nginx/example.com.ssl.error.log;
}

SPA（React/Vue/Angular）設定

シングルページアプリケーションはクライアントサイドルーティングを使用するため、すべてのルートは index.html にフォールバックする必要があります。

# SPA configuration (React, Vue, Angular, Next.js static export)
# /etc/nginx/conf.d/spa.conf

server {
    listen 80;
    server_name spa.example.com;

    root /var/www/spa/dist;
    index index.html;

    # The key directive for SPAs: fallback to index.html
    # This ensures client-side routing works correctly
    location / {
        try_files $uri $uri/ /index.html;
    }

    # Cache JavaScript and CSS bundles (with hash in filename)
    location ~* \.(js|css)$ {
        expires 1y;
        add_header Cache-Control "public, immutable";
        access_log off;
    }

    # Cache images, fonts, and media
    location ~* \.(jpg|jpeg|png|gif|ico|svg|webp|avif|woff|woff2|ttf|eot|mp4|webm)$ {
        expires 30d;
        add_header Cache-Control "public";
        access_log off;
    }

    # Do NOT cache index.html (always serve the latest version)
    location = /index.html {
        expires -1;
        add_header Cache-Control "no-store, no-cache, must-revalidate";
    }

    # API proxy (forward /api requests to the backend)
    location /api/ {
        proxy_pass http://127.0.0.1:4000;
        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;
    }

    # Deny access to source maps in production
    location ~* \.map$ {
        deny all;
    }
}

ロードバランシング

高可用性とパフォーマンス向上のため、受信トラフィックを複数のバックエンドサーバーに分散します。

# Load balancing across multiple backend servers
# /etc/nginx/conf.d/load-balancer.conf

# Define backend server group
upstream app_servers {
    # Round-robin (default) - requests distributed evenly
    server 10.0.0.1:3000;
    server 10.0.0.2:3000;
    server 10.0.0.3:3000;

    # Mark a server as backup (used only when others are down)
    server 10.0.0.4:3000 backup;

    # Health check: mark server down after 3 failed attempts
    # max_fails=3  fail_timeout=30s (default)
}

# Weighted load balancing (send more traffic to powerful servers)
upstream app_weighted {
    server 10.0.0.1:3000 weight=5;   # Gets 5x the traffic
    server 10.0.0.2:3000 weight=3;   # Gets 3x the traffic
    server 10.0.0.3:3000 weight=1;   # Gets 1x the traffic
}

# Least connections (send to the server with fewest active requests)
upstream app_least_conn {
    least_conn;
    server 10.0.0.1:3000;
    server 10.0.0.2:3000;
    server 10.0.0.3:3000;
}

# IP hash (same client always goes to same server - sticky sessions)
upstream app_ip_hash {
    ip_hash;
    server 10.0.0.1:3000;
    server 10.0.0.2:3000;
    server 10.0.0.3:3000;
}

server {
    listen 80;
    server_name lb.example.com;

    location / {
        proxy_pass http://app_servers;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

        # Connection keep-alive to backends
        proxy_http_version 1.1;
        proxy_set_header Connection "";
    }

    # Simple health check endpoint
    location /nginx-health {
        access_log off;
        return 200 "OK";
        add_header Content-Type text/plain;
    }
}

セキュリティヘッダー

HTTPセキュリティヘッダーはクリックジャッキング、XSS、コンテンツインジェクションなどの一般的な攻撃からサイトを保護します。

# Security headers configuration
# Add these inside your server {} block or create a snippet

# /etc/nginx/snippets/security-headers.conf
# Include with: include /etc/nginx/snippets/security-headers.conf;

# Prevent clickjacking: deny embedding in iframes
add_header X-Frame-Options "SAMEORIGIN" always;

# Prevent MIME-type sniffing
add_header X-Content-Type-Options "nosniff" always;

# Enable XSS protection (legacy browsers)
add_header X-XSS-Protection "1; mode=block" always;

# Control referrer information sent with requests
add_header Referrer-Policy "strict-origin-when-cross-origin" always;

# Content Security Policy (customize based on your needs)
add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'unsafe-inline' https://cdn.example.com; style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; img-src 'self' data: https:; font-src 'self' https://fonts.gstatic.com; connect-src 'self' https://api.example.com; frame-ancestors 'self';" always;

# Permissions Policy (formerly Feature-Policy)
add_header Permissions-Policy "camera=(), microphone=(), geolocation=(), interest-cohort=()" always;

# Prevent information leakage
add_header X-Permitted-Cross-Domain-Policies "none" always;

# HSTS (only add if you have SSL configured)
add_header Strict-Transport-Security "max-age=63072000; includeSubDomains; preload" always;

# Hide Nginx version number
server_tokens off;

Gzip 圧縮

Gzip圧縮を有効にすると、転送レスポンスのサイズを最大90%削減でき、ページ読み込み時間を大幅に改善します。

# Gzip compression configuration
# Add inside the http {} block in nginx.conf

# Enable gzip compression
gzip on;

# Minimum file size to compress (skip tiny files)
gzip_min_length 256;

# Compression level (1-9, higher = more CPU, smaller files)
# Level 6 is a good balance between compression ratio and CPU usage
gzip_comp_level 6;

# Number and size of compression buffers
gzip_buffers 16 8k;

# Compress responses for HTTP/1.0 clients too
gzip_http_version 1.0;

# Compress all text-based content types
gzip_types
    text/plain
    text/css
    text/xml
    text/javascript
    application/json
    application/javascript
    application/x-javascript
    application/xml
    application/xml+rss
    application/atom+xml
    application/vnd.ms-fontobject
    font/opentype
    font/ttf
    image/svg+xml
    image/x-icon;

# Add Vary: Accept-Encoding header (important for caching proxies)
gzip_vary on;

# Disable gzip for old IE browsers
gzip_disable "MSIE [1-6]\.";

# Enable gzip for proxied requests too
gzip_proxied any;

レート制限

レート制限は不正使用、ブルートフォース攻撃、DDoSからサーバーを保護します。Nginxの limit_req モジュールはリーキーバケットアルゴリズムを使用します。

# Rate limiting configuration
# Define zones in the http {} block, apply in server/location blocks

# ── Define rate limit zones (in http {} block) ──

# General rate limit: 10 requests/second per IP
limit_req_zone $binary_remote_addr zone=general:10m rate=10r/s;

# Strict rate limit for login/auth: 5 requests/minute per IP
limit_req_zone $binary_remote_addr zone=login:10m rate=5r/m;

# API rate limit: 30 requests/second per IP
limit_req_zone $binary_remote_addr zone=api:10m rate=30r/s;

# Rate limit by server name (protect against virtual host abuse)
limit_req_zone $server_name zone=per_server:10m rate=100r/s;

# ── Apply rate limits (in server {} block) ──

server {
    listen 80;
    server_name api.example.com;

    # Custom error page for rate-limited requests
    error_page 429 = @rate_limited;
    location @rate_limited {
        default_type application/json;
        return 429 '{"error": "Too many requests. Please try again later."}';
    }

    # General pages: allow burst of 20, no delay for first 10
    location / {
        limit_req zone=general burst=20 nodelay;
        limit_req_status 429;
        proxy_pass http://127.0.0.1:3000;
    }

    # Login endpoint: strict rate limiting
    location /api/auth/login {
        limit_req zone=login burst=3 nodelay;
        limit_req_status 429;
        proxy_pass http://127.0.0.1:3000;
    }

    # API endpoints: higher limit with burst
    location /api/ {
        limit_req zone=api burst=50 nodelay;
        limit_req_status 429;
        proxy_pass http://127.0.0.1:3000;
    }

    # Whitelist certain IPs from rate limiting
    # geo $limit {
    #     default 1;
    #     10.0.0.0/8 0;       # Internal network
    #     192.168.0.0/16 0;   # Local network
    # }
    # map $limit $limit_key {
    #     0 "";
    #     1 $binary_remote_addr;
    # }
    # limit_req_zone $limit_key zone=custom:10m rate=10r/s;
}

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