After the installation is finished, I try to login as a root using the "su" command. However, when it asked for the password, I could not login. There is no default/empty password for root.
It turns out you need to set the root password first by using this command:
sudo passwd
Enter new UNIX password:
Retype new UNIX password:
You can also login as a root without setting the password by using this command:
sudo su
