How To Upgrade The Kernel On Centos

How To Upgrade The Kernel On Centos


Upgrading the Linux kernel on CentOS is a process that allows you to take advantage of the latest improvements and optimizations in the kernel. The kernel is the core of the operating system, and upgrading it can improve system performance and security. Upgrading the Linux kernel on CentOS can provide a number of benefits, including improved performance, security, and hardware support. It is important to carefully follow the process to ensure that the upgrade is successful and to minimize the risk of any issues occurring.


Prerequisites and requirements for upgrading the kernel on CentOS include a working installation of CentOS 7, a sufficient amount of free space on your hard drive, and internet access to download the necessary packages.

III.Backup Your System

Before starting the upgrade process, it is essential to create a backup of your system. This will allow you to restore your system to a previous state in case anything goes wrong during the upgrade. There are several tools and techniques available for creating backups, including using tools such as rsync or tar.

IV.Verify the Current Kernel Version

To check the current kernel version on your CentOS system, we use the command

uname -mrs

This command prints the system information, including the kernel version. This command is used to verify the current kernel version best used to keep a track of our kernel version before upgrading to a new version of the kernel.

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Verifying the current version of centos kernel

V.Updating the System Packages

Before upgrading the kernel, it is recommended to update all the installed packages to the latest version. This can be done using the command,

sudo yum update -y

The -y flag is used to automatically answer “yes” when prompted to confirm the update. This step is important to ensure that all the packages are up-to-date and compatible with the new kernel version.

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Updating all the Centos system packages

VI.Adding Elrepo Repository

Elrepo is a third-party repository that provides newer versions of the kernel for CentOS. To add the Elrepo repository, you can use the command,

sudo rpm --import

This command imports the GPG key for the repository, which is used to verify the authenticity of the packages.

Image 9
Adding the Elrepo repository

VII.Installing the Elrepo Repository

Once the GPG key is imported, the Elrepo repository can be installed using the command

sudo rpm -Uvh

This command installs the Elrepo repository on our system, and makes the newer kernel versions available for installation.

Image 10
Elrepo repository being installed

VIII.List All Available Kernels

To see a list of all the available kernels from the Elrepo repository, we use the command,

yum list available --disablerepo='*' --enablerepo=elrepo-kernel
Image 11
This command lists all the available kernels from the Elrepo repository and the version number.

IX.Install New CentOS Kernel Version

To install the new kernel version in CentOs, we use the following command, the ml stands for mainline stable branch this is a rather recent version of the kernel that is installed in CentOs.

sudo yum --enablerepo=elrepo-kernel install kernel-ml
Image 12
Installing the mainline stable branch of the Kernel

To install long term support branch of the Kernel, we execute the following command,

sudo yum --enablerepo=elrepo-kernel install kernel-lt
Image 13
Installing the long term stable branch of the Kernel

X.Reboot the System and Select Kernel

After the new kernel is installed, you need to reboot the system to start using it.

Image 14
Rebooting the system

During the reboot, you will be presented with a GRUB menu, where you can select the new kernel version to boot into.

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Grub Menu during the CentOs startup

XI.Verify the New Kernel Version

After the reboot, you can verify the new kernel version using the command “uname -mrs” again to confirm that the new kernel version is now in use.

uname -mrs
Image 15
Checking if the new kernel is in effect

XII.Set Default Kernel In GRUB After Verification

In order to set the new kernel version as the default, we edit the GRUB configuration file using the command

sudo vim /etc/default/grub
Image 16
Editing the GRUB File

Here we set the default kernel version by editing the line “GRUB_DEFAULT=saved” to “GRUB_DEFAULT=’0′”, where ‘0’ is the latest kernel in the GRUB list.

XIII.Recreating The Kernel Configuration

After the GRUB configuration file is updated in CentOs, you need to recreate the kernel configuration by deploying the following command,

sudo grub2-mkconfig -o /boot/grub2/grub.cfg
Image 17
This command regenerates the GRUB configuration file with

Now, we reboot to check if the changes took place,

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Voila! we are all set with the new Kernel