https://blog.technologyofkevin.com/?p=591
see http://sueboy.blogspot.tw/2017/11/nginx-proxy-pass-best-practices.html
http://sueboy.blogspot.tw/2017/11/nginx-proxy-pass-best-practices-2-for.html
nginx -t
after the test ran successful, I can restart the service/etc/init.d/nginx restart
or only reload the nignx site configs without a restartnginx -s reload
