How To Create an SSL Certificate on Apache for CentOS 7
在CentOS 设置一个 SSL 加密的网页服务器
https://wiki.centos.org/zh/HowTos/Https
https://www.digitalocean.com/community/tutorials/how-to-secure-apache-with-let-s-encrypt-on-centos-7
Crontab Generator
httpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName
Certbot verification fails
Unable to find a virtual host listening on port 80 which is currently needed for Certbot to prove to the CA that you control your domain. Please add a virtual host for port 80.
https://www.digitalocean.com/community/questions/certbot-verification-fails