Migrate CentOS 8 Operating System to AlmaLinux - CentLinux


Tuesday, 6 July 2021

Migrate CentOS 8 Operating System to AlmaLinux


AlmaLinux is a free and open source alternative to CentOS Linux 8. CentOS 8 is no more, therefore, you should learn how to migrate your operating systems to AlmaLinux.


Table of Contents:


What is AlmaLinux?:

AlmaLinux is a free and open source Linux distribution, created originally by CloudLinux to provide a community-supported, production-grade enterprise operating system that is binary-compatible with Red Hat Enterprise Linux (RHEL). The first stable release of AlmaLinux was published on March 30, 2021.

On December 8, 2020, Red Hat announced that development of CentOS Linux, a free-of-cost downstream fork of the commercial Red Hat Enterprise Linux (RHEL), would be discontinued and its official support would be cut short to focus on CentOS Stream, a rolling release officially used by Red Hat to preview what is intended for inclusion in updates to RHEL.

In response, CloudLinux – which maintains its own commercial Linux distribution, CloudLinux OS – created AlmaLinux to provide a community-supported spiritual successor to CentOS Linux, aiming for binary-compatibility with the current version of RHEL.

On March 30, 2021, the AlmaLinux OS Foundation was created to take over AlmaLinux development and governance from CloudLinux, which has promised $1 million in annual funding to the project. (Courtesy: Wikipedia)


Environment Specification:

We are using a minimal CentOS 8 virtual machine with following specifications.

  • CPU - 3.4 Ghz (2 cores)
  • Memory - 2 GB
  • Storage - 20 GB
  • Operating System - CentOS 8.3
  • Hostname – centos-linux-8.centlinux.com
  • IP Address - /24


Recommended Book:


Checking Current Operating System:

Connect with centos-linux-8.centlinux.com as root user by using a ssh client.

Check the Linux distribution and its version.

# cat /etc/os-release NAME="CentOS Linux" VERSION="8" ID="centos" ID_LIKE="rhel fedora" VERSION_ID="8" PLATFORM_ID="platform:el8" PRETTY_NAME="CentOS Linux 8" ANSI_COLOR="0;31" CPE_NAME="cpe:/o:centos:centos:8" HOME_URL="https://centos.org/" BUG_REPORT_URL="https://bugs.centos.org/" CENTOS_MANTISBT_PROJECT="CentOS-8" CENTOS_MANTISBT_PROJECT_VERSION="8" # cat /etc/centos-release CentOS Linux release 8.3.2011

Check the current Linux Kernel used by your operating system.

# uname -r 4.18.0-240.1.1.el8_3.x86_64


Migrating CentOS 8 Operating System to AlmaLinux:

AlmaLinux provides a bash script to automate the migration process. This script is available for free download at GitHub.

Execute the wget command from Linux command line to download almalinux-deploy.sh script.

# wget https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh --2021-07-04 22:55:09-- https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh Resolving raw.githubusercontent.com (raw.githubusercontent.com)...,,, ... Connecting to raw.githubusercontent.com (raw.githubusercontent.com)||:443... connected. HTTP request sent, awaiting response... 200 OK Length: 26460 (26K) [text/plain] Saving to: ‘almalinux-deploy.sh’ almalinux-deploy.sh 100%[===================>] 25.84K --.-KB/s in 0.09s 2021-07-04 22:55:11 (298 KB/s) - ‘almalinux-deploy.sh’ saved [26460/26460]

Grant execution permissions on almalinux-deploy.sh script.

# chmod +x almalinux-deploy.sh

Now, you can execute the script to start migration process.

Be noted that, if you are migrating from a CentOS version earlier than 8.3, you have to update your CentOS Linux operating system before invoking migration process.

# ./almalinux-deploy.sh


The script first gather the information about your CentOS 8 operating system and then swap the Linux yum repositories with that of AlmaLinux.


The script then identify the software packages that need to be update or install on your Linux server.



After installation of required software packages, the script will end gracefully.

Reboot your machine with newly installed Linux Kernel.

# reboot


You can see that a newly entry pertains to Almalinux has been added in GRUB boot menu.

Press <ENTER> to start your operating system with updated Linux Kernel.


After successful startup, the system will display the CLI based login prompt of Almalinux.


Checking Operating System after Migration:

Login as root user and check the operating system details again.

# cat /etc/os-release NAME="AlmaLinux" VERSION="8.4 (Electric Cheetah)" ID="almalinux" ID_LIKE="rhel centos fedora" VERSION_ID="8.4" PLATFORM_ID="platform:el8" PRETTY_NAME="AlmaLinux 8.4 (Electric Cheetah)" ANSI_COLOR="0;34" CPE_NAME="cpe:/o:almalinux:almalinux:8.4:GA" HOME_URL="https://almalinux.org/" DOCUMENTATION_URL="https://wiki.almalinux.org/" BUG_REPORT_URL="https://bugs.almalinux.org/" ALMALINUX_MANTISBT_PROJECT="AlmaLinux-8" ALMALINUX_MANTISBT_PROJECT_VERSION="8.4" # cat /etc/centos-release AlmaLinux release 8.4 (Electric Cheetah)

Check the version of Linux Kernel again.

# uname -r 4.18.0-305.7.1.el8_4.x86_64

Your CentOS Linux operating system has been migrated to AlmaLinux.



In this installation guide, you have learn how to migrate your CentOS 8 operating system to AlmaLinux. Experiment with this new Linux distro and decide if it could be a better alternative to CentOS Linux 8.

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