Certification Objective 1.13-Downloading the Red Hat Enterprise Linux Installation CDs | Linux Patch Management: Keeping Linux Systems Up To Date

First, this section is not directly related to the Red Hat exams. There is no evidence from the Red Hat Exam Prep guide or course outlines that you need to know how to download and write the RHEL 5 CDs during either exam.

Nevertheless, you need some Red Hat-style Linux distribution to prepare for the Red Hat exams, and this section focuses on whatever steps you need to take to download the relevant media. Obviously, it's best if you have an official subscription to the Red Hat Network, as you may get support for your installation and configuration. However, subscriptions are expensive, and courtesy of the GPL, alternatives are available.

The main alternatives are Fedora Core (versions 5 and 6), as well as the third-party "rebuilds" described earlier. Fedora Core 5/6 is the "testbed" for RHEL 5. While Fedora Core 5 is the "pre-alpha," Fedora Core 6 was used to develop the beta for RHEL 5. In other words, it's what Red Hat used to test many of the features now seen in RHEL 5. In my opinion, the better alternative is one of the rebuild distributions. As described earlier, these distributions are based on the source code for RHEL 5, which Red Hat has released under the GPL.

Several of these groups provide regular updates. As Red Hat releases updates to RHEL 5, these groups rebuild the updated source code into repositories. Most are compatible with the yum update tool. (Starting with release 7, Red Hat has dropped the "Core" from the name of the Fedora distribution.) You can keep these rebuild distributions up to date using yum or another update tool such as smart or apt.

Downloading Red Hat Enterprise Linux

Naturally, if you have a subscription to the Red Hat Network, it's best if you download RHEL 5 CDs directly from the network. Of course, you can purchase a subscription from Red Hat. But if you do not want to spend the money, Red Hat offers a trial subscription to RHEL 5. For more information, see www.redhat.com/rhel/details/eval/. As of this writing, it requires a quick telephone call from a Red Hat sales representative. If approved, you should be able to create a trial account on the Red Hat Network, from where you can download the installation CDs for RHEL 5 and receive updates for the 30-day evaluation period (though Red Hat may revoke this offer at any time). Once you have a Red Hat Network account, navigate to https://rhn.redhat.com, log into your account, click the Channels link on the top bar, and click the link associated with the following statement: download ISO images of channel content. (As Red Hat updates its systems, these URLs and links are subject to change.)

With an authorized Red Hat Network account, you should then be able to download the installation CDs for RHEL 5 in ISO format, using the instructions therein.

As of this writing, Red Hat Enterprise Linux is not available on DVDs, but I believe will be sometime in the near future.

Red Hat Enterprise Linux Source RPMs

As of this writing, you can navigate to the Red Hat FTP server, log in anonymously, and download the source code associated with RHEL 5. You can use commands such as rpmbuild to build the source code packages into binary RPMs that can then be installed.

Unfortunately, it is rather difficult to take these steps with all RHEL 5 source RPMs. Fortunately, a number of third parties have "rebuilt" these source RPMs into working distributions.

Third-Party Rebuilds

When third parties rebuild the RHEL 5 source RPMs, they do so under the GPL. However, they still have to respect various trademark laws that prohibit copying without permission. So when third parties rebuild RHEL 5 packages, they create their own icons, logos, and backgrounds.

However, several rebuild distributions have done more. For example, CentOS (www.centos.org) include installation DVDs and even live CDs similar to those associated with the Ubuntu and Knoppix distributions. They may even be available at the same servers from which you can download other Linux distributions. For example, the CentOS list of mirrors for their (and I say their, because CentOS is a community of developers) rebuild is available from www.centos.org/modules/tinycontent/index.php?id=13.

The Fedora Core 5/6 Prep Option

It's possible to prepare for the Red Hat exams using Fedora Core 5 or 6. Red Hat developed RHEL 5 from this distribution. Fedora Core 5/6 is freely available online and is easily downloadable. It's also available from many other sources, including my book Mastering Fedora Core 5, published by Sybex.

However, Fedora Core 5 is essentially a pre-alpha version of RHEL 5, and as such it may not reflect the RHEL 5 you work with during the Red Hat exams or on the job. While Fedora Core 6 is a bit closer, the software packages will vary. For that reason, I believe if you can't afford a subscription to the Red Hat Network, the best option is one of the third-party rebuild distributions.

An Overview of the Download Process

Whether you download RHEL 5, a rebuild, or Fedora Core 5/6, the basic download process is the same and follows these basic steps:

Select a distribution to download.
Find the download server with ISO files.
Proceed with the download, using a high-speed connection.

Other options are possible; for example, you can install Fedora Core 5/6 or some of the rebuild distributions directly from their Internet servers. As Red Hat supports downloads from HTTP and FTP servers, all you need is a boot disk and a sufficiently high-speed Internet connection. But when you download installation media, you can use that media to install RHEL 5 again and again on multiple computers.

You can then use a command such as cdrecord, or a GUI tool such as GnomeBaker, K3b, or even many Microsoft Windows-based tools to write the ISO file to appropriate blank CDs. The use of GUI tools to write ISO files to CDs (or even DVDs) is fairly trivial. Just look for the menu command that writes the ISO directly to the CD or DVD.

Downloads are not practical without a high-speed connection. (I once tried downloading a Red Hat CD over a telephone modem. After three days, the download file was corrupt and unusable.) If you don't have a high-speed connection, RHEL 5 CDs are available from Red Hat (though they're expensive), or CDs associated with some of the rebuild distributions are available from third parties. For example, the rebuilds created by CentOS and Scientific Linux (www.scientificlinux.org) are available for a modest fee from CheapBytes (www.cheapbytes.com).