[CentOS] Password recovery trick not working on CentOS

Wed May 30 05:54:34 UTC 2018
Nicolas Kovacs <info at microlinux.fr>


I remember back in the days, there was a neat trick to recover a lost
root password, or more exactly, redefine a new password for root.

1. In the bootloader, boot the system with the 'init=/bin/bash' kernel

2. Remount the root partition in read-write mode:

  # mount -o remount,rw /

3. Set the password for root:

  # passwd

4. Remount the root partition in read-only mode:

  # mount -o remount,ro /

5. Switch off the computer.

I tried this out of curiosity on a CentOS 7 sandbox machine, and this
doesn't seem to work anymore. I can boot to a 'bash' console and set the
password OK. But this password doesn't seem to work on the subsequent
normal boot.

Anybody knows why this is so?



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