If you see a warning message similar to "Warning: RPMDB altered outside of yum" when using the yum package manager on Red Hat Enterprise Linux (RHEL), it means that the RPM database on your system has been modified outside of yum.
The RPM database is a central repository of information about all of the packages that are installed on your system. It is used by the package manager (such as yum) to track installed packages and perform operations such as installation, update, and removal of packages.
If the RPM database has been modified outside of yum, it can cause inconsistencies and errors when using the package manager. For example, yum may be unable to determine the correct state of installed packages, or it may report that packages are missing or broken when they are actually installed and functional.
To fix the warning and resolve any issues with the RPM database, you can try the following steps:
yum clean all command to remove all cached data from yum:sudo yum clean all
yum check command to check the consistency of the RPM database:sudo yum check
If the yum check command reports any errors or inconsistencies, you can try repairing the RPM database by running the yum --skip-broken update command:
sudo yum --skip-broken update
This will update all packages that can be updated, and skip any packages that cannot be updated due to errors or dependencies.