Chapter 7. Troubleshooting

This section describes how to troubleshoot and solve package-related issues after the in-place upgrade from both RHEL 6 to RHEL 7 and RHEL 7 to RHEL 8.

7.1. Ensuring that installed packages match the current major RHEL version

Ensure that only packages are installed that have been built for the currently installed major RHEL version:

  1. To display installed packages for a different major RHEL version:

    • On RHEL 7, enter:

      # rpm -aq | grep -v -e '[.]el7' -e '^gpg-pubkey-'
    • On RHEL 8, enter:

      # rpm -aq | grep -v -e '[.+]el8' -e '^gpg-pubkey-' -e '^libmodulemd1-'
  2. Remove or replace the packages reported in the previous step, because they are not supported. For details see the Can I install packages from different versions of RHEL? document.

    If the command in the previous step did not display any output, all installed packages were built for the installed major RHEL version and no further actions are required.

7.2. Fixing dependency errors

After an in-place upgrade, it is possible that packages are installed while some of their dependencies have been removed by the upgrade tool. To solve this problem:

  1. Identify dependencies errors:

    # yum check dependencies

    If the command displays no output, no further actions are required.

  2. To fix dependency errors, reinstall the affected packages. During this operation, the yum utility automatically installs missing dependencies. If the required dependencies are not available in the repositories, install these packages manually.

7.3. Installing missing packages after upgrading to RHEL 7

If you miss certain packages after the upgrade from RHEL 6 to RHEL 7, you probably did not provide a repository to the Red Hat Upgrade Tool that contained these packages. To install these packages after the upgrade, you can use, for example, the following commands:

# cd /root/preupgrade
# bash noauto_postupgrade.d/install_rpmlist.sh kickstart/RHRHEL7rpmlist_kept

Note that different issues can prevent installing the RPMs. In this case, resolve the problems. For further details about other files with lists of packages you should install on the upgraded system, see the /root/preupgrade/kickstart/README file and the pre-upgrade report.

7.4. Known issues

For known issues when upgrading:

  • From RHEL 6 to RHEL 7, see the known issues section in the How do I upgrade from Red Hat Enterprise Linux 6 to Red Hat Enterprise Linux 7 documentation
  • From RHEL 7 to RHEL 8, see the known issues section in the Upgrading from RHEL 7 to RHEL 8 documentation