If you have CentOS 8 installed, there is an automated migration script for you to migrate seamlessly to the latest version of AlmaLinux 8.5 without uninstalling and performing a fresh installation.

Before you start migrating we recommend 3 critical things:

• Full backup of all your files in case something goes wrong
• Verify you have more than 5GB of free storage space (no matter hard drive or solid state drive) to handle the migration process since it will download and re-install files from the binary repository on the Internet
• Make sure the system is running CentOS 8.4 or 8.5. If it’s running any older version, it may encounter an error when running the migration script.

Here is a step by step guide with instructions, code and screenshots:

1. Check the version of CentOS

$ cat /etc/redhat-release
CentOS Linux release 8.5.2111 2. Retrieve the migration shell script from Github $ curl -O https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh 3. Run the script and check its output for errors and migration status / messages: $ sudo bash almalinux-deploy.sh 4. You will see the message “Migration to AlmaLinux is completed” if everything goes well ... Complete!
All Secure Boot related packages which were not released by AlmaLinux are reinstalledOK
BootCurrent: 0007
Timeout: 5 seconds
BootOrder: 0002,0007,0003,0004,0001,0000
Boot0000 FreeBSD
Boot0001* UEFI: Built-in EFI Shell
Boot0003* UEFI: PXE IPv4 Intel(R) Network 18:C0:4D:8D:A1:B5
Boot0004* UEFI: PXE IPv4 Intel(R) Network 18:C0:4D:8D:A1:B6
Boot0007* CentOS Linux
Boot0002* AlmaLinuxThe new EFI boot record for AlmaLinux is added
OK

Migration to AlmaLinux is completed

5. Check the migration to ensure that your system was successfully converted by running the 2 commands below: $ cat /etc/redhat-release
AlmaLinux release 8.5 (Arctic Sphynx) and $ sudo grubby --info DEFAULT | grep
title="AlmaLinux (4.18.0-348.el8.aarch64) 8.5 (Arctic Sphynx)" 6. Reboot the system by: sudo reboot 7. When the system is starting to load the boot menu, you should see AlmaLinux as the first item on the menu:

With that you are done and fully migrated to Alma Linux!

Be sure to check back, our next blog “Migrate CentOS 7 to AlmaLinux, Rocky Linux, Oracle, CentOS Stream 8” is coming soon.

Source: GitHub - AlmaLinux/almalinux-deploy: EL to AlmaLinux migration tool.