Migration guide

NOTE: As this project is newly announced we HIGHLY recommend that you follow system administration best practices and make sure you have backups and/or snapshots of your system before you proceed. It is recommended to do a trial run in a sandbox to verify that migration worked as expected before you attempt to migrate any production system.

This guide contains steps on how to upgrade CentOS 7 to RHEL8 derivatives such as AlmaLinux, CentOS, Oracle, Rocky.

To use this guide you need to install Vagrant and VirtualBox using the following documentation:

• Install VirtualBox

• Install Vagrant

• Clone this repo and cd into it

   git clone https://github.com/AlmaLinux/leapp-data.git
   cd leapp-data

• Start the Virtual Machine.

   vagrant up

• CentOS 7.9 is required to accomplish the upgrade. Login to VM, install the latest CentOS updates, and reboot.

   vagrant ssh
   sudo yum update -y
   sudo reboot

• After reboot login to VM again, download the leapp repo file, and install leapp.

   vagrant ssh
   sudo curl https://repo.almalinux.org/elevate/el7/elevate.repo -o /etc/yum.repos.d/elevate.repo
   sudo yum install leapp -y

• Copy leapp config files for the OS you want to migrate. Possible options are almalinux, centos, eurolinux, oraclelinux, rocky.

   sudo cp /vagrant/files/almalinux/* /etc/leapp/files/

• Start a preupgrade check. It will fail as the default CentOS 7 doesn't meet all requirements for migration. In the meanwhile, Leapp utility creates a special /var/log/leapp/leapp-report.txt file that contains possible problems and recommended solutions. No rpm packages will be installed at this phase.

   sudo leapp preupgrade

This summary report will help you get the picture of whether it is possible to continue the upgrade.

In certain configurations, Leapp generates /var/log/leapp/answerfile with true/false questions. Leapp utility requires answers to all these questions in order to proceed with the upgrade.

• Mentioned fixes from the /var/log/leapp/leapp-report.txt file are mandatory, but you can also review the rest of them if needed.

   sudo rmmod pata_acpi
   echo PermitRootLogin yes | sudo tee -a /etc/ssh/sshd_config
   sudo leapp answer --section remove_pam_pkcs11_module_check.confirm=True

• Start an upgrade. After this process is completed you'll be offered to reboot the system.

   sudo leapp upgrade
   sudo reboot

• A new entry in GRUB called ELevate-Upgrade-Initramfs will appear. The system will be automatically booted into it. See how the update process goes in the VirtualBox console.

• After reboot, login to the system and check how the migration went. Verify that the current OS is the one you need.

  vagrant ssh
  cat /etc/redhat-release
  cat /etc/os-release
  rpm -qa | grep centos
  rpm -qa | grep el7