Arch Linux Kernel Management - ryzendew/Linux-Tips-and-Tricks GitHub Wiki

Arch Linux Kernel Management Guide

Complete beginner-friendly guide to managing kernels on Arch Linux, including installation, removal, switching, and custom kernels.

Table of Contents

  1. Understanding Kernels
  2. Available Kernels
  3. Installing Kernels
  4. Removing Kernels
  5. Switching Kernels
  6. Kernel Parameters
  7. Custom Kernels
  8. Troubleshooting

Understanding Kernels

What is a Kernel?

Kernel is the core of the operating system.

Functions:

  • Manages hardware
  • Handles system resources
  • Provides system calls
  • Controls processes

Kernel Versions

Version format:

6.6.0-arch1
│ │ │ └─── Arch build number
│ │ └───── Patch version
│ └─────── Minor version
└───────── Major version

Kernel Types

Different kernel types:

  • Stable: Latest stable kernel
  • LTS: Long-term support
  • Hardened: Security-focused
  • Zen: Performance-optimized
  • Custom: User-compiled

Available Kernels

Official Kernels

Available in repositories:

  • linux: Latest stable kernel
  • linux-lts: Long-term support kernel
  • linux-hardened: Security-hardened kernel
  • linux-zen: Performance-optimized kernel

Check Installed Kernels

List installed kernels:

# List installed kernels
pacman -Q | grep linux

# Check running kernel
uname -r

Expected output:

linux 6.6.0.arch1-1
linux-headers 6.6.0.arch1-1
linux-firmware 20231215.1b8c0c0-1

Installing Kernels

Install Stable Kernel

Install latest kernel:

# Install kernel
sudo pacman -S linux linux-headers

# For firmware
sudo pacman -S linux-firmware

What gets installed:

  • Kernel image (vmlinuz-linux)
  • Kernel headers (for building modules)
  • Kernel modules

Install LTS Kernel

Install long-term support:

# Install LTS kernel
sudo pacman -S linux-lts linux-lts-headers

Why LTS:

  • More stable
  • Longer support
  • Better for servers
  • Fewer updates

Install Multiple Kernels

Install both stable and LTS:

# Install both
sudo pacman -S linux linux-lts linux-headers linux-lts-headers

Benefits:

  • Fallback option
  • Test new kernel
  • Keep stable option

Install Hardened Kernel

Security-focused kernel:

# Install hardened kernel
sudo pacman -S linux-hardened linux-hardened-headers

Features:

  • Enhanced security
  • Kernel hardening
  • Security patches

Install Zen Kernel

Performance-optimized:

# Install Zen kernel
sudo pacman -S linux-zen linux-zen-headers

Features:

  • Performance tweaks
  • Better desktop responsiveness
  • Optimized for gaming

Removing Kernels

Remove Kernel

Remove specific kernel:

# Remove kernel
sudo pacman -R linux

# Remove with headers
sudo pacman -R linux linux-headers

** Warning**: Don't remove the kernel you're currently using!

Check Running Kernel

Before removing:

# Check current kernel
uname -r

# List installed kernels
pacman -Q | grep linux

Only remove kernels you're not using.

Clean Old Kernels

Remove old kernel versions:

# List old kernels
pacman -Q | grep linux | grep -v $(uname -r)

# Remove old kernels (be careful!)
sudo pacman -R old-kernel-name

Switching Kernels

GRUB Boot Menu

Switch at boot:

  1. Reboot system
  2. Press key when GRUB menu appears
  3. Select kernel from menu
  4. Boot into selected kernel

Set Default Kernel

For GRUB:

# Edit GRUB config
sudo vim /etc/default/grub

Set default:

GRUB_DEFAULT="Advanced options for Arch Linux>Arch Linux, with Linux linux-lts"

Regenerate:

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

systemd-boot

Edit boot entry:

# Edit entry
sudo vim /boot/loader/entries/arch-lts.conf

Change kernel:

linux /vmlinuz-linux-lts
initrd /initramfs-linux-lts.img

Kernel Parameters

What are Kernel Parameters?

Kernel parameters configure kernel at boot.

Common parameters:

  • quiet: Suppress boot messages
  • splash: Show splash screen
  • nomodeset: Disable KMS
  • acpi=off: Disable ACPI

Adding Parameters

For GRUB:

# Edit GRUB config
sudo vim /etc/default/grub

Add parameters:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset"

Regenerate:

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

For systemd-boot

Edit boot entry:

sudo vim /boot/loader/entries/arch.conf

Add to options:

options root=UUID=xxxx-xxxx-xxxx rw quiet splash

Common Parameters

Useful parameters:

  • quiet: Less verbose boot
  • splash: Boot splash
  • nomodeset: Disable KMS (for NVIDIA)
  • acpi=off: Disable ACPI
  • iommu=on: Enable IOMMU
  • mitigations=off: Disable security mitigations (performance)

Custom Kernels

Why Custom Kernel?

Reasons:

  • Remove unused features
  • Add specific features
  • Optimize for hardware
  • Reduce size

Building Custom Kernel

Install build tools:

# Install base-devel
sudo pacman -S base-devel

# Install kernel build tools
sudo pacman -S asp

Get kernel source:

# Get kernel package
asp checkout linux

# Or download from kernel.org
wget https://www.kernel.org/pub/linux/kernel/v6.x/linux-6.6.tar.xz

Configure kernel:

# Copy config
cp /proc/config.gz .
gunzip config.gz
cp config .config

# Or use default
make defconfig

# Customize
make menuconfig

Build kernel:

# Build kernel
make -j$(nproc)

# Install modules
sudo make modules_install

# Install kernel
sudo make install

** Advanced**: Only for experienced users!

Troubleshooting

Kernel Panic

If system won't boot:

  1. Boot from USB
  2. Chroot into system
  3. Install different kernel
  4. Reboot

Module Issues

Rebuild modules:

# Rebuild modules
sudo depmod -a

# Load module
sudo modprobe module-name

Kernel Not Found

Reinstall kernel:

# Reinstall kernel
sudo pacman -S linux linux-headers

# Regenerate initramfs
sudo mkinitcpio -P

Boot Issues

Regenerate initramfs:

# Regenerate for all kernels
sudo mkinitcpio -P

# For specific kernel
sudo mkinitcpio -p linux

Summary

This guide covered:

  1. Kernel basics - What kernels do
  2. Available kernels - Types of kernels
  3. Installing - How to install kernels
  4. Removing - How to remove kernels
  5. Switching - Change kernels
  6. Parameters - Kernel boot options
  7. Custom kernels - Building kernels
  8. Troubleshooting - Common issues

Key Takeaways:

  • Multiple kernels can coexist
  • LTS is more stable
  • Don't remove running kernel
  • Kernel parameters customize boot
  • Custom kernels are advanced

Next Steps

This guide is based on the ArchWiki. For the most up-to-date information, always refer to the official ArchWiki.