How To Reset Root Password on RHEL 7

Overview

If you happen to forgot root password of the server. You have to login to the server with single user and edit the kernel entry and boot and change the root password.

Applies To

CentOS 7, RHEL 7; Tested on CentOS 7

Pre-requisites

Console Access to the system.

Choose Kernel Entry - Core

In order to reset the root password, you need to reboot the server and choose “Core” kernel entry in the “boot” menu option.

When the boot menu is shown; choose the kernel entry as below and press key “e” as shown below.

CentOS Linux (3.10.0-229.11.1.el7.x86_64) 7 (Core)

Note: Boot screen will be shown only for 5 seconds.

Find Kernel Entry – ro

In the “Edit Kernel” option, navigate till you find text “ro” after root device mapper.

Modify Kernel Entry – init

Next, you need to modify the kernel entry as below; which will instruct the kernel to start server into “sh”. To boot the server in single user mode, add the below entry.

rw init=/sysroot/bin/sh

After modifying, press “Ctrl + x”, kernel will be instructed to start in single user mode.

System booting .....

Change Root – sysroot

Execute chroot command or interactive shell with special root directory. Run the command as below;

chroot /sysroot/

Set – Root Password

Now, After running the “chroot” command; in the shell prompt run the command “passwd” along with login username “root” as below to set new password for the root user.

After command execution, Enter the new password and re-enter the new password again.

passwd root

Relabel Filesystem – SELinux

At boot time, init.rc checks for the existence of /.autorelabel. If this file exists, SELinux performs a complete filesystem relabel (using the /sbin/fixfiles -f -F relabel command); and then deletes file /.autorelabel.

To perform the check run the command and reboot the server; after rebooting you can login into the server with newly set password.

touch /.autorelabel

reboot

SlideShare Info

Step by step guide with screenshots is uploaded to slideshare.

How To Reset root Password on CentOS 7 from VCP Muthukrishna