The “Warning: RPMDB altered outside of yum” message in RHEL (Red Hat Enterprise Linux) indicates that the RPM database, which is used by the yum package manager to keep track of installed packages, has been modified in a way that is not consistent with how yum updates it. This can happen if you manually install or remove packages using tools other than yum, such as rpm, alien, or dpkg.
To resolve this issue, you can try repairing the RPM database using the following command:
sudo rpm --rebuilddb
This command rebuilds the RPM database from the installed packages, which should fix any inconsistencies that are causing the “Warning: RPMDB altered outside of yum” message.
If the issue persists, you can try reinstalling the yum package using the following command:
sudo yum reinstall yum
This will reinstall the yum package, which should resolve any issues with the RPM database or other components of the yum system.
If you continue to have issues with the RPM database or with using yum, it may be necessary to reinstall the entire system. Before doing this, be sure to back up any important data to avoid losing it during the reinstallation process.