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

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

Prerequisites

Procedure

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

    # leapp upgrade --target 9.0

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

      # leapp upgrade --target 9.0 --enablerepo <repository_id1> --enablerepo <repository_id2> ...
    • If you are going to upgrade without RHSM or using RHUI, add the --no-rhsm option.
    • 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 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. Complete post-upgrade tasks as described in Performing post-upgrade tasks. Especially, re-evaluate and re-apply your security policies.