sudo root is wrong.
sudo allows you to enter a command with root privileges.
To become root you issue the command su.
Of course for that you need to know the root password... And on ubuntu at least the root account is disbabled by default, needs to be enabled before you can log in as root or use su to become root. Search for the commands to do that.
Also, if you're renting a server or vps you may not even have root access, depending on your hosting plan (this especially if you are renting a managed server).
TBH most things you can achieve with the root account you can also do with sudo.
What you really need it to also have all of the paths and other variables that would be set if you were root. If you add a dash (-) to the su command then it loads the environment of the user you are switching to (i.e. su - bob Will load and run bob's .profile and .bash_rc files). So if you really want to su to root using sudo use :