How to compile your own kernel
Custom Kernel

While not a requirement, compiling the Linux kernel lets you add or remove features depending on your specific needs and possibly make your kernel more efficient.
When people refer to Linux today, they generally mean a Linux distribution, which is composed of the Linux kernel, applications, services, filesystems, and other supporting software. Formally, Linux refers to the Linux kernel, which is the core of all Linux distributions. The kernel manages memory, processes, devices, and system calls. The Linux kernel is the software interface between what we call an operating system and computer hardware.
In this article, you will learn to download, decompress, compile, and install a new Linux kernel onto your system. I'm using a Red Hat Enterprise Linux 8.x system; this procedure should work on all Red Hat Enterprise Linux compatible systems.
Why Compile?
Compiling a Linux kernel is 100 percent optional. Your system will work just fine with a prepackaged Linux kernel. Many enterprises never compile a kernel, and their systems handle workloads without issue.
The primary reason for compiling a kernel is to add features and support that aren't in the kernel by default or to remove some features that are (e.g., virtualization). The kernel, by default, enables virtualization, but not everyone needs or wants this capability. You can selectively remove support for it and work through the compile process to create a leaner kernel that better suits your needs.
Requirements
There are no special skills required to compile a kernel. Although developers use the compilation process, you do not need programming skills. The only skill required is being able to issue commands at a shell prompt and to edit the configuration file should something go amiss during compilation.
You do need root access to the system through sudo
, su
, or direct login as root. In addition to root access, you need the following prerequisites before compiling the kernel:
- The Linux kernel source code
- Sufficient free space on your disk (~20GB or more)
- Developer Tools suite
- Developer support packages
Installing Development Tools
You'll need to install the Development Tools bundle and a few extra packages to be able to set up your system and to compile from source code:
# dnf groupinstall "Development Tools" # dnf -y install ncurses-devel bison flex elfutils-libelf-devel openssl-devel
After the package installations complete, check your system's available disk space (Listing 1).
Listing 1
Checking Available Disk Space
df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 434M 0 434M 0% /dev tmpfs 484M 0 484M 0% /dev/shm tmpfs 484M 6.6M 477M 2% /run tmpfs 484M 0 484M 0% /sys/fs/cgroup /dev/mapper/rhel-root 43G 26G 17G 60% / /dev/sda1 1014M 433M 582M 43% /boot tmpfs 97M 0 97M 0% /run/user/1001
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