Migrating from CentOS 8 to AlmaLinux 8

Support for Centos 8 in the ISPManager control panel was completely discontinued on January 1, 2022. After that, users began to look for an alternative to this OS and found it in AlmaLinux 8. Successful migration is possible using the almalinux-deploy script. This process allows you to save data and system settings with minimal downtime. 

How is the migration performed?

IMPORTANT: The first thing you need to do is create a backup of the server and key directories. Migration involves certain risks, so before performing it, it is important to comply with a number of conditions in order to protect yourself from unnecessary difficulties.

The first stage is preparation

First, check the current version of Centos. You need to make sure that you are using Centos 8. If the current version is lower than 8.5, you need to update to the latest available version. To do this, you will need root privileges. Simply connect to the server via SSH and run the command:

cat /etc/redhat-release

You will also need to update the links to the system repositories using the following commands:

sed -i ‘s/mirrorlist/#mirrorlist/g’ /etc/yum.repos.d/CentOS-*
sed -i ‘s|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g’ /etc/yum.repos.d/CentOS-*

Updating system packages

Next, update the system packages:

sudo yum update -y

Then download the script for converting the OS:

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

Running the conversion script 

The conversion script is run with a single simple command:

bash almalinux-deploy.sh -d

Sometimes users complain that after running the script, they get a “digests SIGNATURES NOT OK” error. In this case, you need to import the AlmaLinux repository GPG key manually and restart the script with the command:

rpm --import https://repo.almalinux.org/almalinux/RPM-GPG-KEY-AlmaLinux && sudo bash almalinux-deploy.sh

Finally, make sure that the conversion to AlmaLinux 8 was successful. The following command will help you with this

cat /etc/redhat-release

If the instructions above did not produce the desired result or you encountered an error during the migration, please contact ISPManager support for advice and a detailed answer to your question.