Chapter 7. Performing post-upgrade tasks on the RHEL 9 system After the in-place upgrade, clean up your RHEL 9 system by remove unneeded packages, disable incompatible repositories, and update the rescue kernel and initial RAM disk. 7.1. Performing post-upgrade tasks This procedure lists major tasks recommended to perform after an in-place upgrade to RHEL 9. Prerequisites The system has been upgraded following the steps described in Performing the upgrade and you have been able to log in to RHEL 9. The status of the in-place upgrade has been verified following the steps described in Verifying the post-upgrade state . Procedure After performing the upgrade, complete the following tasks: Remove any remaining Leapp packages from the exclude list in the /etc/dnf/dnf.conf configuration file, including the snactor package, which is a tool for upgrade extension development. During the in-place upgrade, Leapp packages that were installed with the Leapp utility are automatically added to the exclude list to prevent critical files from being removed or updated. After the in-place upgrade, these Leapp packages must be removed from the exclude list before they can be removed from the system. To manually remove packages from the exclude list, edit the /etc/dnf/dnf.conf configuration file and remove the desired Leapp packages from the exclude list. To remove all packages from the exclude list: Remove remaining RHEL 8 packages, including remaining Leapp packages. Remove the old kernel packages from the RHEL 9 system. For more information on removing kernel packages, see the Red Hat Knowledgebase solution What is the proper method to remove old kernels from a Red Hat Enterprise Linux system? Locate remaining RHEL 8 packages: Remove remaining RHEL 8 packages from your RHEL 9 system. To ensure that RPM dependencies are maintained, use DNF when performing this action. Review the transaction before accepting to ensure no packages are unintentionally removed. For example: Remove remaining Leapp dependency packages: Optional: Remove all remaining upgrade-related data from the system: Important Removing this data might limit Red Hat Support's ability to investigate and troubleshoot post-upgrade problems. Disable DNF repositories whose packages are not RHEL 9-compatible. Repositories managed by RHSM are handled automatically. To disable these repositories: Replace repository_id with the repository ID. Replace the old rescue kernel and initial RAM disk with the current kernel and disk: Remove the existing rescue kernel and initial RAM disk: Reinstall the rescue kernel and related initial RAM disk: If your system is on the IBM Z architecture, update the zipl boot loader: . Optional: Check existing configuration files: Review, remediate, and then remove the rpmnew , rpmsave , and leappsave files. Note that rpmsave and leappsave are equivalent and can be handled similarly. For more information, see What are rpmnew & rpmsave files? Remove configuration files for RHEL 8 DNF modules from the /etc/dnf/modules.d/ directory that are no longer valid. Note that these files have no effect on the system when related DNF modules do not exist. Re-evaluate and re-apply your security policies. Especially, change the SELinux mode to enforcing. For details, see Applying security policies . Verification Verify that the previously removed rescue kernel and rescue initial RAM disk files have been created for the current kernel: Verify the rescue boot entry refers to the existing rescue files. See the grubby output: Review the grubby output and verify that no RHEL 8 boot entries are configured: Verify that no files related to RHEL are present in the /boot/loader/entries file:

Commands:
dnf config-manager --save --setopt exclude=''
rpm -qa | grep -e '\.el[78]' | grep -vE '^(gpg-pubkey|libmodulemd|katello-ca-consumer)' | sort
dnf remove USD(rpm -qa | grep \.el[78] | grep -vE 'gpg-pubkey|libmodulemd|katello-ca-consumer')
dnf remove leapp-deps-el9 leapp-repository-deps-el9
rm -rf /var/log/leapp /root/tmp_leapp_py3 /var/lib/leapp
dnf config-manager --set-disabled <repository_id>
rm /boot/vmlinuz-*rescue* /boot/initramfs-*rescue*
/usr/lib/kernel/install.d/51-dracut-rescue.install add "USD(uname -r)" /boot "/boot/vmlinuz-USD(uname -r)"
zipl
ls /boot/vmlinuz-*rescue* /boot/initramfs-*rescue* lsinitrd /boot/initramfs-*rescue*.img | grep -qm1 "USD(uname -r)/kernel/" && echo "OK" || echo "FAIL"
grubby --info USD(ls /boot/vmlinuz-*rescue*)
grubby --info ALL
grep -r ".el8" "/boot/loader/entries/" || echo "Everything seems ok."