How to Boot into Single User Mode in CentOS 7

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Single User Mode (sometimes known as Maintenance Mode) is a mode in Unix-like operating systems boots into a single user (superuser) where only few services are started at system boot just to provide basic functionality. This mode used mainly for maintenance of multi-user environments and perform certain critical tasks. Some tasks may require exclusive access to shared resources.

Some of those tasks are:

  • Running fsck to check and repair damaged disk partitions
  • Reset root password
  • Fix “failed to mount /etc/fstab” error

In my case, the system just display a black screen after booting process finished. This happened after I update my system packages.

How to Boot into Single User Mode

Turn system on and wait until GRUB boot menu shows up

Boot CentOS 7 Single User Mode 01
GRUB boot menu.

 

Select kernel version and modify

Boot CentOS 7 Single User Mode 02
Modify boot parameter.

Use the ↓ key to find the kernel line (starts with "linux16"), then change the argument ro to rw init=/sysroot/bin/sh as shown in the picture below.

Boot CentOS 7 Single User Mode 03
Modify line starts with linux16.

 

Mount root partition

Your CentOS filesystem is located on /sysroot. To mount this filesystem as your root partition use this command:

# chroot /sysroot

Do the maintenance task

At this point, you can perform all the necessary low-level system maintenance tasks.

Reboot

Once you are done with your maintenance task, reboot the system using this command.

# reboot -f

Final Words

I hope that you now know how to boot into single user mode on Centos 7. If you run into any issues or have any feedback feel free to drop a comment below.

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