There may be some occasion you will end up with requirement to reset the root password, the occasion comes when you forget root password; follow this guide to reset the password of root. In CentOS, single user mode will help us to achieve our goal of resetting root password.
Boot your system in to single user mode.
chroot your system
chroot /sysroot
reset the root password.
passwd
Update SELinux information.
touch /.autorelabel
Exit chroot
exit
Reboot your system.
reboot
Login with new password.
That’s All.