Chapter 5. Performing the upgrade from RHEL 8 to RHEL 9

This procedure lists steps required to perform the upgrade from RHEL 8 to RHEL 9 using the Leapp utility.

Prerequisites

Procedure

  1. On your RHEL 8 system, start the upgrade process: 

    # leapp upgrade

    • If you are using custom repositories from the /etc/yum.repos.d/ directory for the upgrade, enable the selected repositories as follows: 

      # leapp upgrade --enablerepo <repository_id1> --enablerepo <repository_id2> ...
    • If you are upgrading without RHSM or using RHUI, add the --no-rhsm option.
    • If you are upgrading by using an ISO image, add the --no-rhsm and --iso <file_path> options. Replace <file_path> with the file path to the saved ISO image, for example /home/rhel9.iso.
    • If you have an Extended Upgrade Support (EUS), Advanced Update Support (AUS), or Update Services for SAP Solutions (E4S) subscription, add the --channel channel option. Replace channel with the value you used with the leapp preupgrade command, for example, eus, aus, or e4s. Note that you must use the same value with the --channel option in both the leapp preupgrade and leapp upgrade commands.

  2. At the beginning of the upgrade process, Leapp performs the pre-upgrade phase described in Reviewing the pre-upgrade report.

    • If the system is upgradable, Leapp downloads necessary data and prepares an RPM transaction for the upgrade.
    • If your system does not meet the parameters for a reliable upgrade, Leapp terminates the upgrade process and provides a record describing the issue and a recommended solution in the /var/log/leapp/leapp-report.txt file. For more information, see Troubleshooting.

  3. Manually reboot the system: 

    # reboot

    In this phase, the system boots into a RHEL 9-based initial RAM disk image, initramfs. Leapp upgrades all packages and automatically reboots to the RHEL 9 system.

    Alternatively, you can run the leapp upgrade command with the --reboot option and skip this manual step.

    If a failure occurs, investigate logs and known issues as described in Troubleshooting.

  4. Log in to the RHEL 9 system and verify its state as described in Verifying the post-upgrade state of the RHEL 9 system.
  5. Perform all post-upgrade tasks described in the upgrade report and in Performing post-upgrade tasks.