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.
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.
