Amazon AWS/EC2

Accessing Instance
You must change permissions of the key pair to 400.

chmod 400 /path/my-key-pair.pem ssh -i /path/my-key-pair.pem ubuntu@ec2-198-51-100-1.compute-1.amazonaws.com Accessing Instances in Linux

Add Users
http://stackoverflow.com/questions/3260739/add-keypair-to-existing-ec2-instance

pam_ssh
Another handy thing to do is single-sign on. Now that you've authenticated once with your SSH private key, you might as well have it authenticate the password anyway, so you don't have to type it in yet again for sudo.

If you compromise your private key everything is f***ed anyway.

Hostname
Once you get a real domain, you should name your servers with it.

https://aws.amazon.com/premiumsupport/knowledge-center/linux-static-hostname/