CentOS 8 - Recover the Root Password

 This exercise shows the steps required to reset a lost password for the root user.  For this exercise, we use the following command to change the root password to a random string.
# pwmake 128 | passwd --stdin root

The next thing is to reboot the server.  When you see the GRUB menu press E to edit the current menu entry.  Scroll down until the line starting with linux.  Press CTRL-E or END to move to the end of the line, and then add the string rd.break.

Press CTRL-X to boot the system.

The rd.break directive interrupts the boot sequence before the root filesystem is properly mounted.  Confirm this by running ls /sysroot.  The output should look something below.

Remount the root /sysroot filesystem as read-write and change the root directory to /sysroot:
# mount -o remount, rw /sysroot
# chroot /sysroot

Follow by the passwd command to change the root password:
# passwd

Because SELinux is not running, the passwd command does not preserve  the context of the /etc/passwd file.  To ensure that the /etc/passwd file is labeled with the correct SELinux context, instruct Linux to relabel all files at the next boot with the following command:
# touch / .autorelabel

Type exit to close the chroot jail, and then type exit again to reboot the system.