Let's Encrypt is CA that offers free SSL certificates to everyone. This is one of the most meaningful project I ever seen. The certificates it offers has a short valid period of 3 months. Certbot is a command line tool that allows you to request new certificates, revoke/delete certificates, install certificates, and automatically renew the certificates.

Basic Usage

This command installs certbot (SSL cert for https)

yum install certbot-apache
certbot --authenticator standalone --installer apache -d yourdomain.com --pre-hook "systemctl stop httpd" --post-hook "systemctl start httpd"

First command installs Certbot Apache plugin. Second command installs Certbot for your site.

To include root and subdomains into 1 cert:

certbot --authenticator standalone --installer apache --expand -d yourdomain.com -d www.example.com --pre-hook "systemctl stop httpd" --post-hook "systemctl start httpd"

Expand Certificate

Adding domains to existing certificate. Useful for adding www to root domain.

certbot --expand -d existingdomain.com -d newdomain.com

Delete Certificate

certbot delete

Renew Certificate

certbot renew --apache