Admin User
The admin user will be your remote access user for maintenance, upgrades, etc. Use this user instead of root going forward.
Create the admin user (and record the password somewhere secure).
adduser admin
Then add the admin user to sudoers (enabling the sudo command for this user). Update the sudoers file.
/etc/sudoers
Lock down this server so that only the admin user can access it. Change or add these lines to your SSH config:
/etc/ssh/sshd_config
Restart SSH.
service ssh restart
Switch to the admin user now, and create an RSA key. Change the comment to reflect the name of this server, e.g. "admin@app-server". Press [enter] when prompted to accept the default location.
su - admin
ssh-keygen -t rsa -C "admin@build-server" -qN ""
Finally, you should have a RSA key on your local machine (if you don't, you should make one!). Copy your public key to the authorized keys of the admin user. This will allow you to log in from your local machine without using a password.
echo "yourpublickey" >> ~/.ssh/authorized_keys