Modify the System Bootloader | RHCSA

Introduction

As a system administrator, you may need to modify the system bootloader to customize the boot process or troubleshoot boot-related issues. In this challenge, you will learn how to modify the GRUB bootloader configuration on a Red Hat Enterprise Linux (RHEL) system.

Modify the GRUB Bootloader Configuration

Your task is to modify the main GRUB configuration file to change the default kernel that the system boots into. This involves editing a configuration file and then running a command to apply the changes to the bootloader menu.

Tasks

Modify the /etc/default/grub file to set a new default kernel.
Regenerate the GRUB configuration file to apply the change.

Requirements

Edit the /etc/default/grub file using a text editor like nano.
Locate the GRUB_DEFAULT parameter and change its value to 2.
After modifying the file, regenerate the GRUB configuration file by running sudo grub2-mkconfig -o /boot/grub2/grub.cfg.

Hints

You will need sudo privileges to edit /etc/default/grub and to run grub2-mkconfig.
The grub2-mkconfig command reads settings from /etc/default/grub to generate the main configuration file, which is located at /boot/grub2/grub.cfg.

Note: A system reboot is normally required to boot with the new default kernel. However, in this lab environment, you should NOT reboot the system. LabEx VMs are one-time use, and a reboot will cause loss of challenge progress.

Summary

In this challenge, you learned how to modify the system bootloader (GRUB) configuration to change the default kernel option. This involved editing the /etc/default/grub file and regenerating the configuration with grub2-mkconfig. This skill is essential for system administrators who need to customize the boot process or troubleshoot boot-related issues on a RHEL system.