프록시와 VPN

upstream backend {
    least_conn;                         # 최소 연결 알고리즘
    server 127.0.0.1:3001 weight=3;     # 가중치 3
    server 127.0.0.1:3002 weight=1;     # 가중치 1
    server 127.0.0.1:3003 backup;       # 백업 서버
}

server {
    listen 80;
    server_name example.com;
    return 301 https://$host$request_uri;  # HTTP → HTTPS 리다이렉트
}

server {
    listen 443 ssl http2;
    server_name example.com;

    ssl_certificate     /etc/ssl/cert.pem;
    ssl_certificate_key /etc/ssl/key.pem;

    # 정적 파일 직접 서빙 (백엔드 거치지 않음)
    location /static/ {
        root /var/www;
        expires 30d;
        add_header Cache-Control "public, immutable";
    }

    # API는 백엔드로 프록시
    location /api/ {
        proxy_pass http://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;

        # 타임아웃 설정
        proxy_connect_timeout 5s;
        proxy_read_timeout 30s;
    }

    # WebSocket 지원
    location /ws/ {
        proxy_pass http://backend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }
}