Boot in single user mode on CentOS 7 / RHEL 7

Oh Dear! monitors your entire site, not just the homepage. We crawl and search for broken pages and mixed content, send alerts when your site is down and notify you on expiring SSL certificates.

Start your free 10 day trial! »

Image of Mattias Geniar

Mattias Geniar, September 28, 2015

Follow me on Twitter as @mattiasgeniar

This guide will show you how to boot into single user mode on a CentOS 7 server. You'll need single user boot to recover a corrupt file system, reset the root password, ...

First, reboot your server and when you enter the Kernel Selection menu, press e to modify the parameters to boot the kernel.

centos7 single user mode 1

The next screen will show you a confusing screen of kernel parameters. It’ll look like this.

centos7 single user mode 2

Scroll down until you find the actual kernel line. It starts with linux16 /vmlinuz-... and will span a couple of lines. You’re now looking for the ro keyword in the kernel linux, which would start the OS with a read only (ro) file system.

centos7 single user mode 3

Use your arrow keys to go to the ro line and replace it with rw init=/sysroot/bin/bash. The result should look like this. If that’s the case, press ctrl+x to boot the kernel with those options.

centos7 single user mode 4

If everything went fine, you’re now in a limited shell with access to the entire filesystem. To make things easier, you can chroot the filesystem so you can access all your known files/directories with the same paths.

centos7 single user mode 5

After you typed chroot /sysroot/, you’ll find your familiar files in /etc, /usr,/var, …

If you’re done working in single user mode, reboot again by pressing ctrl+alt+del.

Update: as a reader pointed out, you may have to remount the filesystem from readonly to read-write, too.

mount -o remount,rw /

After that, you should be able to make changes to files on the disk that persist on reboot.

Will you help me share this post?

It would mean a lot to me if you could help share this post on social media. 🤗