Red Hat SummitChapter 5. Troubleshooting
Troubleshoot and solve package-related issues after the in-place upgrade from RHEL 6.10 to RHEL 7.9.
5.1. Troubleshooting resources
You can refer to the following troubleshooting resources.
Console Output
By default, only error and critical log level messages are printed to the console output by the Pre-upgrade Assistant. To also print debug, info, and warning messages, use the --debug option with the redhat-upgrade-tool command.
Logs
The /var/log/upgrade.log file lists issues found during the upgrade phase.
Reports
The /root/preupgrade/result.html file lists issues found during the pre-upgrade phase. This report is also available in the web console. For more information, see Assessing upgrade suitability from a web UI.
5.2. Fixing dependency errors
During an in-place upgrade, certain packages might be installed without some of their dependencies.
Procedure
Identify dependencies errors:
# yum check dependencies
If the command displays no output, no further actions are required.
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To fix dependency errors, reinstall the affected packages. During this operation, the
yumutility automatically installs missing dependencies. If the required dependencies are not provided by repositories available on the system, install those packages manually.
5.3. Installing missing packages
Certain packages might be missing after the upgrade from RHEL 6 to RHEL 7. This problem can occur for several reasons:
- You did not provide a repository to the Red Hat Upgrade Tool that contained these packages. Install missing packages manually.
- Certain problems are preventing some RPMs from being installed. Resolve these problems before installing missing packages.
- You are missing NetworkManager because the service was not configured and running before the upgrade. Install and configure NetworkManager manually. For more information, see Getting started with NetworkManager.
Procedure
Review which packages are missing from your RHEL 7 system using one of the following methods:
- Review the pre-upgrade report.
Run the following command to generate a list of expected packages in RHEL 7 and compare with the packages that are currently installed to determine which packages are missing.
$ /root/preupgrade/kickstart/RHRHEL7rpmlist* | grep -v "#" | cut -d "|" -f 3 | sort | uniq
Install missing packages using one of the following methods:
Locate and install all missing packages at once. This is the quickest method of getting all missing packages.
# cd /root/preupgrade # bash noauto_postupgrade.d/install_rpmlist.sh kickstart/RHRHEL7rpmlist_kept
If you know that you want to install only some of the missing packages, install each package individually.
# yum install package
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.
5.4. Known issues
The following are issues known to occur when upgrading from RHEL 6 to RHEL 7:
- In-place upgrade from a RHEL 6 system to RHEL 7 is impossible with FIPS mode enabled
- In-place upgrade on IBM Z fails and causes a data loss if the LDL format is used
- The Preupgrade Assistant reports notchecked if certain packages are missing on the system
- redhat-upgrade-tool fails to reconfigure the network interfaces, preventing the upgrade to happen
- redhat-upgrade-tool fails to reconfigure the static routes on the network interfaces, preventing the upgrade to happen
- Why does Red Hat Enterprise Linux 6 to 7 in-place upgrade fail if /usr is on separate partition?
- Systems on the IBM Power, big endian architecture that use multipath volumes might experience issues during the in-place upgrade, causing the upgraded system to fail to boot. To prevent this issue, do not perform the in-place upgrade on such systems. (BZ #1704283)
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If the target RHEL 7 repository contains the
kernel-3.10.0-1160.62.1.el7package or newer, the upgrade fails. This results in a broken system in an unbootable state. To prevent this issue, use the RHEL 7.9 GA repository without z-stream updates or ensure that the RHEL 7.9 kernel inside the repository is older than thekernel-3.10.0-1160.62.1.el7package. (RHEL-3292)
5.5. Rolling back the upgrade
If the in-place upgrade to RHEL 7 is unsuccessful, it is possible to get the previous RHEL 6 working system back in limited configurations using one of the following methods:
- The rollback capability integrated in the Red Hat Upgrade Tool. For more information, see Rollbacks and cleanup after upgrading RHEL 6 to RHEL 7.
- A custom backup and recovery solution, for example, the Relax-and-Recover (ReaR) utility. For more information, see the ReaR documentation and What is Relax and Recover (ReaR) and how can I use it for disaster recovery?.
