Differences with Ubuntu 18.04 - richnadeau/Tech-Journal-SYS265 GitHub Wiki

To change the hostname, use #hostnamectl set-hostname

You can then change /etc/cloud/cloud.cfg file so that you can preserve the hostname. (Change line that says preserve_hostname: false to true)

When adding a user to Ubuntu use adduser instead of useradd like in centos. Useradd will make a user without a directory while adduser will make the user and their own directory.