Nginx maintenance site

nginx-maintenance-server

server {
        listen 80 default_server;
        listen [::]:80 default_server ipv6only=on;

        root /usr/share/nginx/html;
        server_name localhost;

        # 503.html: https://gist.github.com/pitch-gist/2999707
        error_page 503 /503.html;

        location = /503.html {
                internal;
        }

        location / {
                return 503;
        }

}