First, add the root user after Ubuntu enters the system.

Because ubuntu does not have a root user by default, although you can also use sudo to execute some root permissions for winter, but in case, I mean that sudo or some other systems and configuration files are broken. to install the sudo tool, you need the root permission. You need to wait for the tragedy. The first one is to add the root user!

Sudo passwd Root

Use this command to change the root password and enter the root password you want to create. Haha, you can directly log on to the system using the root user.