letsencrypt憑證更新後，但伺服器(nginx/apache/tomcat)不會autoreload

letsencrypt更新了憑證後，web server並不會知道憑證要重新讀取， 此時可利用letsencrypt的hooks機制，

以nginx為例，在以下路徑寫一個可執行的shell script: 

/etc/letsencrypt/renewal-hooks/deploy/01-reload-nginx 

 ============================ 

#! /bin/sh 

set -e 

nginx -t

systemctl reload nginx

============================ 

 這樣每次renew憑證時，就會重新載入憑證了。 

 ref: 

https://eff-certbot.readthedocs.io/en/stable/using.html#renewing-certificates

https://www.guyrutenberg.com/2017/01/01/lets-encrypt-reload-nginx-after-renewing-certificates/

https://www.javatpoint.com/starting-and-restarting-nginx