How to Install or upgrade to Kernel 6.x on CentOS Stream 8

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

Step 1 - Find current kernel version

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Use the uname command to display the current version of kernel the system is running.:

uname -sr

Output:

[root@vps ~]# uname -sr
Linux 4.18.0-394.el8.x86_64

Step 2 - Enable ELRepo

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Import the public key and install the ELRepo RPM package using the below command.

rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
dnf install https://www.elrepo.org/elrepo-release-8.el8.elrepo.noarch.rpm

Output:

[root@vps ~]# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
[root@vps ~]# dnf install https://www.elrepo.org/elrepo-release-8.el8.elrepo.noarch.rpm
Last metadata expiration check: 1:26:24 ago on Tue 03 Jan 2023 02:10:56 PM UTC.
elrepo-release-8.el8.elrepo.noarch.rpm                       41 kB/s |  13 kB     00:00
Dependencies resolved.
============================================================================================
Package                Architecture   Version                   Repository            Size
============================================================================================
Upgrading:
elrepo-release         noarch         8.3-1.el8.elrepo          @commandline          13 k

Transaction Summary
============================================================================================
Upgrade  1 Package

Total size: 13 k
Is this ok [y/N]: y
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing        :                                                                    1/1
Upgrading        : elrepo-release-8.3-1.el8.elrepo.noarch                             1/2
Cleanup          : elrepo-release-8.0-2.el8.elrepo.noarch                             2/2
Verifying        : elrepo-release-8.3-1.el8.elrepo.noarch                             1/2
Verifying        : elrepo-release-8.0-2.el8.elrepo.noarch                             2/2

Upgraded:
elrepo-release-8.3-1.el8.elrepo.noarch

Complete!

Once the repository has been enabled, you can use the following command to list the available kernel related packages:

dnf --disablerepo="*" --enablerepo="elrepo-kernel" list available

Output:

[root@vps ~]# dnf --disablerepo="*" --enablerepo="elrepo-kernel" list available
ELRepo.org Community Enterprise Linux Kernel Repository - el8                                1.2 MB/s | 2.1 MB     00:01
Available Packages
bpftool.x86_64                                                6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-lt.x86_64                                              5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-lt-core.x86_64                                         5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-lt-devel.x86_64                                        5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-lt-doc.noarch                                          5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-lt-headers.x86_64                                      5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-lt-modules.x86_64                                      5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-lt-modules-extra.x86_64                                5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-lt-tools.x86_64                                        5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-lt-tools-libs.x86_64                                   5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-lt-tools-libs-devel.x86_64                             5.4.228-1.el8.elrepo                              elrepo-kernel
kernel-ml.x86_64                                              6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-ml-core.x86_64                                         6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-ml-devel.x86_64                                        6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-ml-doc.noarch                                          6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-ml-headers.x86_64                                      6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-ml-modules.x86_64                                      6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-ml-modules-extra.x86_64                                6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-ml-tools.x86_64                                        6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-ml-tools-libs.x86_64                                   6.1.2-1.el8.elrepo                                elrepo-kernel
kernel-ml-tools-libs-devel.x86_64                             6.1.2-1.el8.elrepo                                elrepo-kernel
perf.x86_64                                                   6.1.2-1.el8.elrepo                                elrepo-kernel
python3-perf.x86_64                                           6.1.2-1.el8.elrepo                                elrepo-kernel

Step 3 - Install kernel

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Run the following command to install the latest mainline stable kernel:

dnf --enablerepo=elrepo-kernel install kernel-ml

Output:

[root@vps ~]# dnf --enablerepo=elrepo-kernel install kernel-ml
ELRepo.org Community Enterprise Linux Repository - el8                                       205 kB/s | 239 kB     00:01
ELRepo.org Community Enterprise Linux Kernel Repository - el8                                1.3 MB/s | 2.1 MB     00:01
Last metadata expiration check: 0:00:01 ago on Tue 03 Jan 2023 01:29:37 PM UTC.
Dependencies resolved.
=============================================================================================================================
 Package                          Architecture          Version                           Repository                    Size
=============================================================================================================================
Installing:
 kernel-ml                        x86_64                6.1.2-1.el8.elrepo                elrepo-kernel                 98 k
Installing dependencies:
 kernel-ml-core                   x86_64                6.1.2-1.el8.elrepo                elrepo-kernel                 34 M
 kernel-ml-modules                x86_64                6.1.2-1.el8.elrepo                elrepo-kernel                 30 M

Transaction Summary
=============================================================================================================================
Install  3 Packages

Total download size: 64 M
Installed size: 100 M
Is this ok [y/N]: y
Downloading Packages:
(1/3): kernel-ml-6.1.2-1.el8.elrepo.x86_64.rpm                                               168 kB/s |  98 kB     00:00
(2/3): kernel-ml-modules-6.1.2-1.el8.elrepo.x86_64.rpm                                       9.9 MB/s |  30 MB     00:02
(3/3): kernel-ml-core-6.1.2-1.el8.elrepo.x86_64.rpm                                           11 MB/s |  34 MB     00:03
-----------------------------------------------------------------------------------------------------------------------------
Total                                                                                         19 MB/s |  64 MB     00:03
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                                                     1/1
  Installing       : kernel-ml-core-6.1.2-1.el8.elrepo.x86_64                                                            1/3
  Running scriptlet: kernel-ml-core-6.1.2-1.el8.elrepo.x86_64                                                            1/3
  Installing       : kernel-ml-modules-6.1.2-1.el8.elrepo.x86_64                                                         2/3
  Running scriptlet: kernel-ml-modules-6.1.2-1.el8.elrepo.x86_64                                                         2/3
  Installing       : kernel-ml-6.1.2-1.el8.elrepo.x86_64                                                                 3/3
  Running scriptlet: kernel-ml-core-6.1.2-1.el8.elrepo.x86_64                                                            3/3
  Running scriptlet: kernel-ml-6.1.2-1.el8.elrepo.x86_64                                                                 3/3
  Verifying        : kernel-ml-6.1.2-1.el8.elrepo.x86_64                                                                 1/3
  Verifying        : kernel-ml-core-6.1.2-1.el8.elrepo.x86_64                                                            2/3
  Verifying        : kernel-ml-modules-6.1.2-1.el8.elrepo.x86_64                                                         3/3

Installed:
  kernel-ml-6.1.2-1.el8.elrepo.x86_64  kernel-ml-core-6.1.2-1.el8.elrepo.x86_64  kernel-ml-modules-6.1.2-1.el8.elrepo.x86_64

Complete!

Step 4 - Verify the kernel version

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By default, the system will set the newly installed kernel as the default version to use and boot with.

You can verify this by running the below command,

grubby --default-kernel

Once confirmed, reboot the system to boot with the latest kernel installed. This can be further verified by running the uname command,

uname -r

Output:

[root@vps ~]# uname -r
6.1.2-1.el8.elrepo.x86_64