Once you have a VPS running, create a user called jenkins with sudo privileges:
root@ci:# adduser jenkinsroot@ci:# usermod -aG sudo jenkins
Then, to allow us to log into the server as the power-restricted user jenkins and not root, we must first add the public key of our development machine to /home/jenkins/.ssh/authorized_keys; the easiest way to do that is to copy the /root/.ssh/ directory and change its owner:
root@ci:# cp -R /root/.ssh/ /home/jenkins/root@ci:# chown -R jenkins:jenkins /home/jenkins/.ssh/
Then, disable password authentication and root login by editing /etc/ssh/sshd_config:
PermitRootLogin noPasswordAuthentication no
Reload the SSH daemon for the new settings to take effect:
root@ci:# systemctl ...
