Reset Forgotten root Password in CentOS 8
First, reboot or power on your Redhat 8/CentOS 8 system. Select the kernel you want to boot into. Next, press ‘e’ on the keyboard to interrupt the boot process and make changes.
On the next screen, locate the ro (read-only) kernel parameter as highlighted below.
Replace the kernel parameter ro with rw and append an extra kernel parameter init=/sysroot/bin/sh. In a nutshell, simply replace the kernel parameter ro with rw init=/sysroot/bin/sh.
Once done with making the changes, hit Ctrl + X combination on the keyboard to enter single-user mode.
Next, run the command below to mount the root file system in read and write mode.
:/# chroot /sysroot
You can now change the root password by executing the command:
:/# passwd root
Provide a new root password and confirm it. For best practice select a password with a combination of uppercase, lowercase, numerical and special characters to boost password strength.
Next, run the command below to enable SELinux relabelling.
:/# touch /.autorelabel
To apply the changes, exit and reboot the Redhat 8/CentOS 8 system.
:/# exit :/# reboot
Upon reboot, the SELinux relabelling process will commence. Give it about 3 minutes.
When the relabeling process is done, the system will reboot and thereafter, you will be get logon screen and you can able to login successfully with the new password which you just set