Let's Encrypt & Certbot

add-apt-repository ppa:certbot/certbot
apt-get update && apt-get install python-certbot

yum install epel-release
yum install python-certbot

You must stop anything on port 443/80 before starting certbot

certbot certonly --standalone  -d example.com

You can use the crt/privkey from this path

ls /etc/letsencrypt/live/example.com

cert.pem chain.pem fullchain.pem privkey.pem README

If you need a DH for you web.conf you can do

openssl dhparam -out /etc/ssl/certs/dhparam.pem 2048

crontab -e

15 3 * * * /usr/bin/certbot renew --quiet