Background

One of our Linux CentOS machines is not booting up.

Error Messages

Image

Textual

Troubleshooting

Outline

1. BIOS
   • Hardware Specifications
2. Emergency Mode
   • Command
     • LVS

BIOS

Hardware Specifications

Please access the computer’s BIOS.

Review the Hardware; specifically Hard-drive.

If your hard-drive is not present.

Or is marked faulty, then you have found your problem.

 

Emergency Mode

Access Emergency mode.

Command

LVS

Syntax

lvs

 

Sample

lvs --all

 

Output – Textual

 

Output – Image

 

 

Remediation

1. Emergency Mode
   • Rebuild initramfs

Emergency Mode

Access or stay in emergency mode.

Rebuild initramfs

Commands

dracut

Syntax

dracut --regenerate

 

Sample

dracut --regenerate-all -f

 

Output – Image ( Without force )

Output – Textual ( Without force )

>sudo dracut --regenerate-all
[sudo] password : 
dracut: Will not override existing initramfs (/boot/initramfs-4.18.0-348.7.1.el8_5.x86_64.img) without --force
dracut: Will not override existing initramfs (/boot/initramfs-4.18.0-383.el8.x86_64.img) without --force
dracut: Will not override existing initramfs (/boot/initramfs-4.18.0-408.el8.x86_64.img) without --force

Output – Textual ( With force )

>sudo dracut --regenerate-all -f
[sudo] password : 

 

Explanation

1. Please issue “dracut –regenerate -f” to actually force a rebuild of your initramfs

 

grub2-mkconfig

Syntax

grub2-mkconfig

 

Sample – BIOS

If you are booting up via BIOS, please pass along /boot/grub2/grub.cfg

grub2-mkconfig -o /boot/grub2/grub.cfg

 

Sample – UEFI

If you are booting up via UEFI, please pass along /boot/efi/EFI/redhat/grub.cfg

grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg

 

Output – Image ( Without force )

Output – Textual

generating grub configuration file..

Explanation

1. Please determine ahead of time whether your are running legacy bios or the more modern UEFI

 

Summary

In summary, if you run into the error:-

Please do the following:-

1. Check your hard-drive
   • Access BIOS and run hardware tests
   • Attempt to use 3rd party hardware diagnostic tools
2. Access Emergency Mode
   • Issue LVM Command ( Logical Volume Manager )
     • Review LVM Listing
   • Rebuild initramfs
     • dracut –regenerate-all
     • grub2-mkconfig

 

Referenced Work

1. Stack Exchange
   • Unix & Linux
     • Error booting Linux root and swap does not exist
       Link
2. The Geek Diary
   • “dracut-initqueue[286]: Warning: dracut initqueue timeout – starting timeout scripts” – CentOS/RHEL 7 booting issue
     Link
3. Ubuntu
   • Initramfs
     Link
4. LinuxFromScratch.Org
   • Beyond Linux® From Scratch (System V Edition) – Version r11.2-942
     • Chapter 5. File Systems and Disk Management
       About initramfs
       Link