certbot-centos7

yum install certbot python2-certbot-nginx
certbot --nginx
#certificate only
certbot certonly --nginx
#create for certain domain
certbot -d subdomainname
#setup automatic renewal
echo "0 0,12 * * * root python -c 'import random; import time; time.sleep(random.random() * 3600)' && certbot renew" | sudo tee -a /etc/crontab > /dev/null
#check ssl quality at https://www.ssllabs.com/ssltest/