For some reason, perhaps you don't want to run a daemon or let Letsencrypt have access to your production server.
There is a way to use it like a normal CSR/CA setup in manual mode.
./letsencrypt-auto certonly --manual -d realtechtalk.com - www.realtechtalk.com
Eventually you will get prompted to create a certain path and file with certain data:
Create a file containing just this data:
./certbot-auto --apache certonly
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator apache, Installer apache
No names were found in your configuration files. Please enter in your domain
name(s) (comma and/or space separated) (Enter 'c' to cancel): yourdomain.com
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for yourdomain.com