proxy를 사용할 때, client IP를 backend에 전달하기

# nginx.conf
server {
    listen 80;
    server_name my-backend.com;

    location / {
        proxy_pass http://backend-server:8080;

        # Preserve client IP
        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;

        # Preserve original host
        proxy_set_header Host $host;
    }
}

# 재기동
sudo systemctl restart nginx