If you have a redhat VM, take a snapshot of your virtual machine
Remember that this is the best practice in IT industry & we can revert to previous state if we face any big problem. Also taking clones & configuration backup are other method we use in IT industry.
Reboot the Virtual Machine
Press any key to stop boot process of the OS
Now select your kernal from boot menu and press ‘e’ to edit it
From the grub options, find the line that starts with “linux16” and go to the end of it. Enter ‘rd.break’ without quotes at the end of this line
Now Press “Ctrl+x” to boot with these saved options. This will load the root shell
In this mode the root file system is mounted in read only mode to /sysroot and must be remounted with read/write (rw) permissions because we are going to change root . To do this use command ‘mount -o remount,rw /sysroot’ command.
now change in to chroot jail. Then command we execute only apply to to sysroot. We must do this part and use below command.
Now reset password using ‘passwd’ command
now we need to create autorelabel because in this mode files will not be overwrite and /etc/shadow file will keep same and no changes will be applied to root password.
so create a autorelabel using ‘touch /.autorelabel’
now everything is fine and enter ‘exit’ twice and you will see logout on screen and vm will be rebooted
after reboot access your server using new password