This article explains how to reset the root password if you no longer know it. You will require KVM access to your server in order to perform these steps.
CentOS/Fedora
- Through the KVM, initiate a restart of your server by sending the shutdown command:
- When it comes to the Loading CentOS/Fedora Grub Bootloader screen hit esc. (Right after you get to the network boot screen it will be at the grub bootloader screen)
- At the grub screen select the default OS & hit "e" to edit.
- Then you should see 3 lines of text. Select the line that starts with kernel & ends in root=label=/
- Press "e" to edit the line, and at the end of the line add a space and then put a capital "S".
- Then enter to save & go back to the previous screen.
- Then hit "b" for boot with that line selected.
- It will enter you in single-user mode and you get a bash prompt.
- Then you can just type ”passwd” enter the new password and reboot.
You will not need to re-edit the grub loader it reverts to normal after the next reboot.
Debian
Reboot and edit the Grub kernel line add a space then the following at the end of the line. (like ‘Alternate Method’ above)
Then run this command to remount the root partition in read/write mode.
and reset the root password as normal with the "passwd" command.