NOTE: CentOS Enterprise Linux 5 is built from the Red Hat Enterprise Linux source code. Other than logo and name changes CentOS Enterprise Linux 5 is compatible with the equivalent Red Hat version. This document applies equally to both Red Hat and CentOS Enterprise Linux 5.
To start, first make sure that you have all necessary resources for the installation. If you have already read through Chapter 2, Steps to Get You Started, and followed the instructions, you should be ready to start the installation process. When you have verified that you are ready to begin, boot the installation program using the Red Hat Enterprise Linux DVD or CD-ROM #1 or any boot media that you have created.
Note
Occasionally, some hardware components require a driver diskette during the installation. A driver diskette adds support for hardware that is not otherwise supported by the installation program. Refer to Chapter 7, Driver Media for Intel and AMD Systems for more information.
4.3.1. Booting the Installation Program on x86, AMD64, and Intel® 64 Systems
You can boot the installation program using any one of the following media (depending upon what your system can support):
Red Hat Enterprise Linux DVD/CD-ROM — Your machine supports a bootable DVD/CD-ROM drive and you have the Red Hat Enterprise Linux CD-ROM set or DVD.
Boot CD-ROM — Your machine supports a bootable CD-ROM drive and you want to perform network or hard drive installation.
USB pen drive — Your machine supports booting from a USB device.
PXE boot via network — Your machine supports booting from the network. This is an advanced installation path. Refer to Chapter 31, PXE Network Installations for additional information on this method.
Insert the boot media and reboot the system. Your BIOS settings may need to be changed to allow you to boot from the CD-ROM or USB device.
Tip
To change your BIOS settings on an x86, AMD64, or Intel® 64 system, watch the instructions provided on your display when your computer first boots. A line of text appears, telling you which key to press to enter the BIOS settings.
Once you have entered your BIOS setup program, find the section where you can alter your boot sequence. The default is often C, A or A, C (depending on whether you boot from your hard drive [C] or a diskette drive [A]). Change this sequence so that the CD-ROM is first in your boot order and that C or A (whichever is your typical boot default) is second. This instructs the computer to first look at the CD-ROM drive for bootable media; if it does not find bootable media on the CD-ROM drive, it then checks your hard drive or diskette drive.
Save your changes before exiting the BIOS. For more information, refer to the documentation that came with your system.
After a short delay, a screen containing the boot: prompt should appear. The screen contains information on a variety of boot options. Each boot option also has one or more help screens associated with it. To access a help screen, press the appropriate function key as listed in the line at the bottom of the screen.
As you boot the installation program, be aware of two issues:
Once the boot: prompt appears, the installation program automatically begins if you take no action within the first minute. To disable this feature, press one of the help screen function keys.
If you press a help screen function key, there is a slight delay while the help screen is read from the boot media.
Normally, you only need to press Enter to boot. Be sure to watch the boot messages to review if the Linux kernel detects your hardware. If your hardware is properly detected, continue to the next section. If it does not properly detect your hardware, you may need to restart the installation and use one of the boot options provided in Chapter 8, Additional Boot Options for Intel and AMD Systems.
4.3.2. Booting the Installation Program on Itanium Systems
Your Itanium system should be able to boot the Red Hat Enterprise Linux installation program directly from the Red Hat Enterprise Linux CD #1. If your Itanium cannot boot the installation program from the CD-ROM (or if you want to perform a hard drive, NFS, FTP, or HTTP installation) you must boot from an LS-120 diskette. Refer to Section 4.3.2.2, “Booting the Installation Program from an LS-120 Diskette” for more information.
4.3.2.1. Booting the Installation Program from the DVD/CD-ROM
To boot from the Red Hat Enterprise Linux CD #1 follow these steps:
Remove all media except Red Hat Enterprise Linux CD #1.
From the Boot Option menu choose EFI Shell.
At the Shell> prompt, change to the file system on the CD-ROM. For example, in the above sample map output, the system partition on the CD-ROM is fs1. To change to the fs1 file system, type fs1: at the prompt.
Type elilo linux to boot into the installation program.
4.3.2.2. Booting the Installation Program from an LS-120 Diskette
If your Itanium cannot boot from Red Hat Enterprise Linux CD #1, you must boot from an LS-120 diskette. If you want to perform a hard drive, NFS, FTP, or HTTP installation, you must boot from boot LS-120 diskette.
You must create an LS-120 boot image file diskette from the boot image file on CD #1: images/boot.img. To create this diskette in Linux, insert a blank LS-120 diskette and type the following command at a shell prompt:
dd if=boot.img of=/dev/hda bs=180k
Replace boot.img with the full path to the boot image file and /dev/hda with the correct device name for the LS-120 diskette drive.
If you are not using the Red Hat Enterprise Linux CD, the installation program starts in text mode and you must choose a few basic options for your system.
To boot from an LS-120 diskette follow these steps:
Insert the LS-120 diskette you made from the boot image file boot.img. If you are performing a local CD-ROM installation but booting off the LS-120 diskette, insert the Red Hat Enterprise Linux CD #1 also. If you are performing a hard drive, NFS, FTP, or HTTP installation, you do not need the CD-ROM.
From the Boot Option menu choose EFI Shell.
At the Shell> prompt, change the device to the LS-120 drive by typing the command fs0:, using the example map output above.
Type elilo linux to boot into the installation program.
While it is easiest to boot using a CD-ROM and perform a graphical installation, sometimes there are installation scenarios where booting in a different manner may be needed. This section discusses additional boot options available for Red Hat Enterprise Linux.
For Itanium users:
To pass options to the boot loader on an Itanium system, enter the following at the EFI Shell prompt:
elilo linux option
For x86, AMD64, and Intel® 64 users:
To pass options to the boot loader on an x86, AMD64, or Intel® 64 system, use the instructions as provided in the boot loader option samples below.
To perform a text mode installation, at the installation boot prompt, type:
linux text
ISO images have an md5sum embedded in them. To test the checksum integrity of an ISO image, at the installation boot prompt, type:
linux mediacheck
The installation program prompts you to insert a CD or select an ISO image to test, and select OK to perform the checksum operation. This checksum operation can be performed on any Red Hat Enterprise Linux CD and does not have to be performed in a specific order (for example, CD #1 does not have to be the first CD you verify). It is strongly recommended to perform this operation on any Red Hat Enterprise Linux CD that was created from downloaded ISO images. This command works with the CD, DVD, hard drive ISO, and NFS ISO installation methods.
Also in the images/ directory is the boot.iso file. This file is an ISO image than can be used to boot the installation program. To use the boot.iso, your computer must be able to boot from its CD-ROM drive, and its BIOS settings must be configured to do so. You must then burn the boot.iso file onto a recordable/rewriteable CD-ROM.
If you need to perform the installation in serial mode, type the following command:
linux console=<device>
For text mode installations, use:
linux text console=<device>
In the above command, <device> should be the device you are using (such as ttyS0 or ttyS1). For example, linux text console=ttyS0.
Text mode installations using a serial terminal work best when the terminal supports UTF-8. Under UNIX and Linux, Kermit supports UTF-8. For Windows, Kermit '95 works well. Non-UTF-8 capable terminals works as long as only English is used during the installation process. An enhanced serial display can be used by passing the utf8 command as a boot-time option to the installation program. For example:
linux console=ttyS0 utf8
4.3.3.1. Kernel Options
Options can also be passed to the kernel. For example, to apply updates for the anaconda installation program from a floppy disk enter:
linux updates
For text mode installations, use:
linux text updates
This command will prompt you to insert a floppy diskette containing updates for anaconda. It is not needed if you are performing a network installation and have already placed the updates image contents in rhupdates/ on the server.
After entering any options, press Enter to boot using those options.
If you need to specify boot options to identify your hardware, please write them down. The boot options are needed during the boot loader configuration portion of the installation (refer to Section 4.19, “x86, AMD64, and Intel 64 Boot Loader Configuration” for more information).
