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:

1.  Full backup of all your files in case something goes wrong
2.  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
3.  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
 

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$ cat /etc/redhat-release 
CentOS Linux release 8.5.2111

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2.     Retrieve the migration shell script from Github

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$ curl -O https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh

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3.     Run the script and check its output for errors and migration status / messages:

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$ sudo bash almalinux-deploy.sh

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4.     You will see the message “Migration to AlmaLinux is completed” if everything goes well

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...
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

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5.     Check the migration to ensure that your system was successfully converted by running the 2 commands below:

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$ cat /etc/redhat-release
AlmaLinux release 8.5 (Arctic Sphynx)

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and

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$ sudo grubby --info DEFAULT | grep AlmaLinux
title="AlmaLinux (4.18.0-348.el8.aarch64) 8.5 (Arctic Sphynx)"

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6.     Reboot the system by:

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sudo reboot

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7.     When the system is starting to load the boot menu, you should see AlmaLinux as the first item on the menu: