How to Upgrade from CentOS 7 to AlmaLinux 8 or 9 Print

CentOS 7 is nearing its end-of-life support, making it critical to migrate to a modern OS like AlmaLinux. This guide provides a step-by-step process to upgrade your server from CentOS 7 to AlmaLinux 8 or 9 using the ELevate tool.

Prerequisites:

• VPS or dedicated server running CentOS 7.
• Root or sudo user access.
• A complete backup of all data.
• Ensure the system is up-to-date.

Step-by-Step Upgrade Process

1. Prepare Your System

1. Update all system packages:
   sudo yum update -y
2. Reboot the server to apply updates:
    

   sudo reboot
3. Confirm the current version:
    

   cat /etc/centos-release

2. Install the ELevate Tool

1. Add the ELevate repository:
    

   sudo yum install -y https://repo.almalinux.org/elevate/elevate-release-latest-el7.noarch.rpm
2. Install the leapp package:
    

   sudo yum install -y leapp

3. Check Compatibility

1. Run the pre-upgrade check:
    

   sudo leapp preupgrade
2. Review the compatibility report at /var/log/leapp/leapp-report.txt.
3. Address any issues outlined in the report.

4. Start the Upgrade

1. Run the upgrade command:
    

   sudo leapp upgrade
2. Reboot the system:
    

   sudo reboot
   Your server will boot into a special initramfs environment to complete the upgrade.

5. Verify the Upgrade

1. Log in and verify the version:
    

   cat /etc/redhat-release
   It should indicate AlmaLinux 8 or 9.

6. Post-Upgrade Steps

1. Reinstall or update any third-party repositories.
2. Test all services and applications.
3. Clean up unused packages:
    

   sudo yum autoremove

Troubleshooting

• Check logs if issues arise:
  • /var/log/leapp/leapp-upgrade.log
  • /var/log/leapp/leapp-report.txt
• Ensure adequate disk space.
• Disable conflicting third-party repositories.

Conclusion

Upgrading from CentOS 7 to AlmaLinux 8 or 9 is essential for continued support and security. This guide helps ensure a smooth transition with minimal downtime.