While there are many Linux users who prefer other tools for doing their patch management, yum is designed for RPM-based distributions. Its popularity has grown as Fedora Linux has adapted yum as its primary patch management tool. Because the Red Hat Network is not available unless you're a subscriber, many RHEL rebuild distributions have also adapted yum for updates and more.
The repository creation process can be time-consuming. If you use packages from installation CDs, you can save some time. With the rsync command, you can download the remaining packages that you need. The advantage of rsync is that you can keep your repositories up to date with the same commands that you've used to download the packages you need.
When created, you'll need to share your repositories. There are three major sharing services: NFS, Apache, and FTP. When shared, you can configure your clients to point to the repositories on your local network, minimizing the loads on your Internet connection, allowing you to focus on those packages critical to security and functionality on your network.
While you can use the Red Hat Network Proxy Server described in Chapter 2 to manage patches and updates on RHEL computers, you can also configure a yum repository based on an amalgamation of RHEL installation packages and updates.
We've covered a broad array of patch management tools that you can use on almost any Linux distribution. There are other excellent tools exclusive to specific distributions, such as uprmi for Mandriva and emerge for Gentoo. Our lack of coverage of these tools is not intended to denigrate these excellent tools but simply reflects the scope of this book.