Install Let's Encrypt and Create an SSL Certificate

Note: Use Certbot for easy management of Let's Encrypt SSL certificates.

Install git:
CentOS: yum install git
Debian / Ubuntu: apt-get install git

Clone Let's Encrypt to /opt directory
git clone https://github.com/letsencrypt/letsencrypt /opt/letsencrypt

Create a Certificate
cd /opt/letsencrypt
-H ./letsencrypt-auto --apache -d example.com -d www.example.com