Linux

Dedicated subjects

Restore root password

RHEL/CentOS

Reboot the server, and press e to edit the GRUB command line.

Add rd.break at the end of the linux16 line and press ctrl-x to boot in single user mode.

Mount the filesystem in rw:

mount -o remount,rw /sysroot

Chroot inside the folder:

chroot /sysroot

Then change the root password:

passwd root

If SELinux is installed and running, don’t forget to relabel the FS:

touch /.autorelabel

Type exit twice and you are done.