Reset root password in CentOS 6

In CentOS base version , I mean v6 there is a bug and you cant reset the password in the usual way. I am going to mention both the ways.

To reset root password of CentOS machine, Start your PC. You will get GRUB screen and there choose " e" to edit booting kernel. After that It will open in a new window with current configuration.

If you observe there you can find a line with two last words like  " rhgb quiet \" Dont worry about "\" , use backspace and remove " rghb quiet". Then add in that line as " a 1 " and then press F10 key to boot. it will successfully boot into /bin/sh and there by using passwd command you can reset the root  password of the server.

If its not working .

1 . SELinux may be causing the problem , to take care of it you have to restart Machine and again edit GRUB , but this time we have to one more parameter extra.

Now add parameters like " a selinux=0 1 " , So CentOS will boot into /bin/sh with permissive mode of selinux.

2. Authentication Token manipulation error

Simple , the root partition has mounted as read-only so you are unable to write( password update -new password writing ) anything to root directory. so you have to remount it with read-write access & of course you are a root user .

mount -o remount, rw /

So after that try again with passwd command to reset the password.

Hope it helps.