RHCE Red Hat Certified Engineer Linux Study Guide (Exam RH302), Fourth Edition [Electronic resources] نسخه متنی

Certification Objective 2.02: Downloading the Red Hat Installation CD-ROMs

To study for the RHCE or RHCT exam, you need to practice with a copy of a Red Hat Linux distribution. Ideally, you should work with a copy of Red Hat Enterprise Linux 3. Unfortunately, it is expensive. But assuming you have a high-speed connection, there are options.

RHEL 3 is based on Red Hat Linux 9. If you install and update this operating system, you can use Red Hat Linux 9 to study for the exams. Just be sure that you have the appropriate version of any software that you're studying. Alternatively, you could even use the version of Fedora Linux (Yarrow) released in November 2003. It's a mixed bag; that Fedora Linux release includes some updates that are in RHEL 3, and others that go beyond RHEL 3.

If you don't have a high-speed connection, downloading the gigabytes of files associated with the latest versions of RHEL can take several days. If Red Hat Linux 9 or Fedora Linux is all that you can or want to afford, and you can accept the differences with Red Hat Enterprise Linux 3, you can purchase downloaded CDs from a source such as CheapBytes (www.cheapbytes.com) or buy a book with the publisher's edition of Red Hat Linux 9. Alternatively, there are third parties who have built RHEL 3 from the publically available source RPMs. I describe these options in more detail in the Introduction to this book.

Generally, these downloaded CDs are available in ISO format, which you can process and write to CDs using the methods I describe in this section.

Red Hat Enterprise Linux

As described in the introduction to this book, you can buy a copy of RHEL. Assuming you have a PC with an Intel-style 32-bit CPU, you can purchase the most inexpensive version of this server, Red Hat Enterprise Linux ES. As of this writing, you can purchase the Basic Edition with a one-year subscription to the Red Hat Network for $349. At this price, RHEL ES 3 is available only by download in ISO format; for all practical purposes, this requires a high-speed connection.

While there are versions of RHEL available with packaged CDs, they are significantly more expensive. Once again, let me repeat my belief that you can use Red Hat Linux 9 or the RHEL rebuilds to study for the RHCE and RHCT exams based on RHEL 3.

Red Hat Enterprise Source RPMs

Red Hat provides free access to the source RPMs for Red Hat Enterprise Linux 3 (RHEL). You can download these source RPMs from Third-Party Red Hat Enterprise Linux

As I've described in the introduction to this book, there are third-party versions of RHEL 3 available. They are built from the source code RPMs that Red Hat has made freely available, under the Linux General Public License (GPL). While I am not a lawyer, my understanding is that these third parties have complied with the following guidelines:

Software in RHEL 3 that is not licensed under the GPL must not be included. As I understand it, this includes some packages supplied by IBM and not covered on the Red Hat exam.

All software in the third-party version of RHEL 3 must be built from the source code (despite what you might see on eBay, my understanding is that you can't just resell copies of the RHEL binary RPMs, especially the installation CDs).

References to 'Red Hat' must be removed from the software.

Binary updates, such as through up2date or the Red Hat Network, are not allowed. However, this does not exclude updates from revised GPL source code.

As I've described in the introduction, there are three major groups working on a rebuild of RHEL 3. As of this writing, each of these groups have made their work available in ISO format through their Web sites (and mirrors), which you can write to CDs using the techniques I describe shortly.

Red Hat Linux 9 or Fedora

RHEL 3 is based on Red Hat Linux 9. It includes some improvements that are included in the first release of Fedora Linux in late 2003. Therefore, you could prepare for the RHCE or RHCT exams using one or both of these operating system distributions.

However, these operating systems are not identical. For example, while Red Hat Linux 9 uses the samba-2.2.7 RPM package for sharing with Microsoft Windows computers, RHEL 3 uses the samba-3.0.0 RPM package. With the current Red Hat development model, Red Hat will use Fedora to test some future changes to RHEL. Today, the differences between RHEL 3, Red Hat Linux 9, and the Fedora Linux released in late 2003 are fairly small. However, I believe that the differences between RHEL 4 and Fedora (or its successor) will be more substantial. I'm guessing RHEL 4 will be released in 2005.

If you don't have a copy of Red Hat Enterprise Linux 3, I recommend that you study with one of the third-party rebuilds of RHEL 3.

An Overview of the Download Process

If you have a high-speed connection, downloading Red Hat operating system CD-ROMs is fairly easy. If you've purchased Red Hat Enterprise Linux, follow the Red Hat Network download instructions. If you want to download the Red Hat Linux 9 or Fedora Installation CDs, just connect to www.tucows.com) or www.linuxiso.org, and start your download. If you're downloading a third-party rebuild of RHEL 3, navigate to their Web sites for more information. Since FTP is optimized for file transfer, FTP clients are the best way to download a Linux distribution.

There are two ways to download and prepare Red Hat Installation files: as individual files or as ISO packages. You can install from ISO packages on a hard drive. You can also install from ISO packages or a directory of RPM files on an HTTP, FTP, or NFS server.

Once you've downloaded the installation files or ISOs, you're ready to install the Red Hat operating system, possibly with the help of the appropriate boot disk as described later in this chapter.

Downloading Installation Files

If you have 2GB of available disk space, you can download the Red Hat operating system installation files. Create a RedHat directory or subdirectory on your hard disk, and copy the files from the /RedHat directory on the FTP server. I'll show you shortly how you can use this to set up a network installation server.

On your computer, direct the download to a /RedHat directory (or subdirectory). Organize the files in the /RedHat directory with the same subdirectories that you can find on a Red Hat installation CD. Make sure to include both the /base and /RPMS subdirectories. When you perform the download, make sure you also copy the hidden .discinfo file on the first installation CD.

Downloading Red Hat Linux on ISO Files

An ISO is a single file that is associated with a large package of files, usually on a CD. Once you download an ISO, you can use a number of tools to extract the files to a CD-ROM. There are four binary installation ISOs associated with Red Hat Enterprise Linux 3. Alternatively, the third-party rebuilds (as of this writing) have consolidated the RHEL 3 software on three binary installation ISOs.

As long as you have a high-speed connection, it's easy to download the appropriate ISOs. I describe the lftp client in Chapter 7. Once you've downloaded the three Red Hat installation ISOs, use the tool of your choice to extract the contents to a writable CD. For example, the following command records the /tmp/RedHat/rhcd1.iso file, at 2x speed, to a blank writable CD on the first CD drive on your computer:

# cdrecord -v speed=2 dev=0,0,0 /tmp/RedHat/rhcd1.iso

If you need more information on recording CDs, refer to the CD-Writing HOWTO available from www.tldp.org. Alternatively, you can mount the ISO as if it were a CD. For example, the following command mounts the aforementioned ISO file:

# mount -t iso9660 -ro loop /tmp/RedHat/rhcd1.iso /mnt/cdrom

You don't even need to extract the files from the ISO. Just use the /mnt/cdrom directory as if it were a real CD.

It's easy to check the integrity of each installation CD. Reboot your computer with the first Red Hat Enterprise Linux installation CD. Type linux mediacheck at the prompt; the RHEL 3 installation program takes you to the screen shown in Figure 2-1 where you can test each CD.