Reset/Recover Root Password
Follow below procedure on how to break root password of CentOS 8.
- First, you need console access: Either at a keyboard and monitor locally, or via Virtual Machine remote console, you will need to see and interact with the bootloader.
- Reboot the machine: As soon as the bootloader comes up with the selection screen, quickly tap the up and down arrows up and down to pause the countdown.
Select the kernel you want to boot into, and hit ‘e’: - This will take you into a screen where you can edit the grub bootloader script.
- Find the line that refers to the kernel: There will be a series of ‘boot parameters’ here: these are instructions passed during the loading of the kernel.
- For RHEL/Centos 8x, and Fedora the line starts with ‘linux’.
Add ‘rd.break’ at the end of that line.
(For more refer to video tutorial) - Now hit Ctrl-x to run the edited bootloader script.
- You’ll boot to a ‘rescue’ prompt that looks like this: switch_root:/#.
- Remount the root partition in read-write mode so that you can run commands. Enter the following: mount -o remount rw /sysroot and then hit ENTER.
- Now type
chroot /sysroot and hit enter. This will change you into the sysroot (/) directory, and make that your path for executing commands.
10. Now you can simply change the password for root using the passwd command.
11. Next, before you reboot, you will need to make sure that SELinux allows the file changes. At the prompt ,enter: touch /.autorelabel. This will signal SELinux on the next reboot that the filesystem has changed (the changed password) and allow the change to be loaded.
12. This will cause the whole filesystem to be ‘relabeled’ which might take a while, depending on the size of the filesystem and the speed of the machine, so be aware of this possibility.
13. Type exit to leave the chroot environment and type exit again.
Now depending on the RAM memory you have given to your machine, it will take time to reboot.