You can use CertBot to install free SSL Certificates on servers with or without hosting panels.
You can follow instructions here for various setups https://certbot.eff.org/instructions
I use Centos 7 & Nginx with one setup, this presumes you have added running sites to nginx and want to enable SSL.
Enable Epel-Release for Centos 7
Code:
yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
Install CertBot
Code:
yum install certbot python2-certbot-nginx
Run Certbot & follow the prompts
Code:
certbot --nginx
Optional Run this command to add a cron task to auto renew certificates
Code:
echo "0 0,12 * * * root python -c 'import random; import time; time.sleep(random.random() * 3600)' && certbot renew -q" | sudo tee -a /etc/crontab > /dev/null
You can test your new certificates here
Code:
https://www.ssllabs.com/ssltest/