Certbot letsencrypt tutorial

Avoid using python2 for certbot as it has deprecated.

cd /etc/letsencrypt/
virtualenv -p python3 venv3
source venv3/bin/activate
certbot certonly --standalone  -d your-domain.com

# renew ssl certificates
/etc/letsencrypt/venv3/bin/certbot renew 

Refer to: github info