Migrating from CentOS 8 to AlmaLinux 8

You can switch from using CentOS 8 to AlmaLinux 8:

• on the server with VMmanager;
• on the VMmanager cluster node.

Migration is performed using the almalinux-deploy script. We recommend that before you migrate:

• a server with VMmanager, you create a platform backup;
• a cluster node, you create a backup of the virtual machines (VMs) of that node.

To migrate:

1. Connect to the server via SSH.

2. Check the OS version: 

   cat /etc/redhat-release

3. If the OS version is lower than 8.5, change the paths to the repositories: 

   sed -i -r 's|^(mirrorlist.+)$|#\1|g; s|^#baseurl=http://mirror.centos.org/\$contentdir/\$releasever/|baseurl=https://vault.centos.org/8.5.2111/|g' /etc/yum.repos.d/CentOS-*.repo

4. Install the latest software updates:

   sudo yum update -y

5. Download the migration script:

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

6. Stop the platform: 

   vm stop

7. Run the script:

   sudo bash almalinux-deploy.sh

   Message on successful script execution

   Migration to AlmaLinux is completed

8. If the script run fails with an error like 

   Example of error

   Verify almalinux-release-latest.rpm package                           ERROR
       /root/.alma.X46iDx/almalinux-release-latest.rpm: digests SIGNATURES NOT OK

   import the GPG key of the AlmaLinux repository manually and restart the script:

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

9. Check that AlmaLinux has been installed:

   cat /etc/redhat-release

   Example of reply

   AlmaLinux release 8.5 (Arctic Sphynx)

10. Check that the AlmaLinux kernel is loaded by default:

    sudo grubby --info DEFAULT | grep AlmaLinux

    Example of reply

    title="AlmaLinux (4.18.0-348.el8.x86_64) 8.5 (Arctic Sphynx)"

11. Start the platform: 

    vm start