How to Upgrade Linux Kernel on CentOS 7

The kernel is a central component of an operating system that manages the operations of the computer and hardware. It basically manages operations of memory and CPU time. It is a core component of an operating system. Kernel acts as a bridge between applications and data processing performed at the hardware level using inter-process communication and system calls. 

Like any other software, Linux Kernel also needs an update periodically. Linus Torvalds releases the new updates to the Linux Kernels. Every update typically includes fixes to security loopholes, bug fixes to problems, better hardware compatibility, improved stability, more speed, and occasionally major updates also bring some new functions and features. In this article, we’re going to upgrade the CentOS 7 kernel.

Note: To get more understanding of the kernel please check this article

Updating the Kernel

Follow the below steps to upgrade the kernel:

Note: Make sure you’re executing each command as a root user or with the sudo privileges

Step 1: Check the current kernel version

uname -mrs

Checking current version

Step 2: Update CentOS package repositories

yum update -y

updating packages…

Updating repositories

Step 3: Enable the Elrepo repository

Add the ELRepo gpg key to the system.

rpm –import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

Add the new Elrepo repository

rpm -Uvh https://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpm

Adding Elrepo repository

Step 4: List available kernel versions

yum list available –disablerepo=’*’ –enablerepo=elrepo-kernel

Step 5: Install the latest kernel version

To install stable long-term support release:

yum –enablerepo=elrepo-kernel install kernel-lt

to install a mainline release then change kernel-lt to kernel-ml 

Installing kernel

As you can see we’ve successfully installed the long-term support kernel release.

Step 6: Reboot and choose the latest kernel to boot

Rebooting to latest kernel

Verify the kernel version:

Step 7: Set default kernel version

Edit the default grub file with your preferred editor and change GRUB_DEFAULT=saved to GRUB_DEFAULT=0

vim /etc/default/grub

Recreate the kernel configuration

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

Recreating kernel config

Finally, reboot to verify that the latest kernel entry will be by default selected.