I've launched an Amazon EC2 instance of Ubuntu Server 12.04 and it's all fine except, unlike with my local Ubuntu, the EC2 instance never asks for any passwords when I'm sudoing with the command line or become root. I tried
passwd
# asks for a new password, I supply one
sudo -i
# always makes me root right away
passwd
# asks for a new password, I supply one
passwd ubuntu
# asks for a new password, I supply one
(ubuntu
is the default user the instance gets installed with.) So far, event after reboots, I haven't noticed any difference, it still never asks for any passwords.
It's not a biggie but I guess I've just used to how my local Ubuntu works.