Chapter 2: InstallationOverview

Part 1

• Installing Fedora/RHEL is the process of copying operating system files from media to the local system and setting up configuration files so Linux runs properly on the hardware.

• You can install Linux from many types of media: including a CD/DVD, the local hard disk, a USB flash drive, or a hard disk on another system that is accessed over a network.

• Several types of installations are possible, including fresh installations, upgrades from older versions of Fedora/RHEL, dual-boot installations, and virtual machine installations.

• You can perform the installation manually or set up Kickstart to install Fedora/RHEL automatically.

The Desktop Live CD and the Install DVD

• Live CD: the Fedora Desktop Live Media• A live CD runs Fedora without installing it on

the system.• When you boot from this CD, it brings up a

GNOME/KDE desktop: You are running a live session.

• You can install Fedora from a live session. Red Hat Enterprise Linux does not provide a live session.

The Desktop Live CD and the Install DVD

• An install DVD does not bring up a desktop before you install Fedora/RHEL.

• When you boot an install DVD, it brings up a menu that allows you to install Fedora/RHEL.

The Desktop Live CD and the Install DVD

• The Net Boot CD (formerly the Boot CD) boots a system and displays the same menu as an install DVD (above).

• It does not hold the software packages needed to install Fedora/RHEL but does allow you to install a new system from a hard disk or over a network.

Planning the Installation

Considerations

• SELinux (Security Enhanced Linux) improves system security by implementing mandatory access control policies in the Fedora/RHEL kernel .

• By default, Fedora installs SELinux in Enforcing mode. • If you do not plan to use SELinux, you can change it to

Permissive mode once the system is installed. • When you install RHEL, if you plan to use SELinux

under RHEL, allow it to remain in Enforcing mode, or change it to Permissive mode, but do not disable it during Firstboot.

Considerations

• GUI: On most installations (except for servers), you will probably want to install a graphical desktop environment.

• GNOME is installed by default. You can also install KDE or both GNOME and KDE.

• On a server, you normally dedicate as many resources to the server as possible and few resources to anything not required by the server. For this reason, dedicated servers rarely include a graphical interface.

Requirements

• Hardware: Fedora/RHEL can run on many different types of hardware.

• On 32-bit Intel and compatible platforms such as AMD and VIA as well as 64-bit platforms such as AMD64 processors , Intel processors with Intel Extended Memory 64 Technology (EM64T) including the Core and Core 2 series, and Intel Itanium (IA-64) processors.

• Fedora/RHEL usually runs on the same systems that Windows runs on, unless the system includes a very new or unusual component.

Requirements

• Memory (RAM): You need a minimum of 128 megabytes of RAM for a 32-bit x86 system that runs in text mode (no GUI) and 192–256 megabytes for a graphical system.

• For a 64-bit x86_64 system, you need at least 256 megabytes for text mode and 384–512 megabytes for a graphical system.

• Linux makes good use of extra memory: The more memory a system has, the faster it will run.

Requirements

• CPU: Fedora requires a minimum of a 200-megahertz Pentium-class processor or the equivalent AMD or other processor for textual mode.

• Fedora graphical mode and RHEL require at least a 400-megahertz Pentium Pro or Pentium II processor or the equivalent.

Requirements

• Hard disk space: The amount of hard disk space you need depends on which version of Fedora/RHEL you install, which packages you install, how many languages you install, and how much space you need for user data (your files).

• The operating system can occupy from about 300 megabytes to more than 9 gigabytes.

Requirements

• BIOS: Modern computers can be set to boot from a CD/DVD, floppy diskette, hard disk,or USB flash drive, and from the network via a PXE server.

• The BIOS determines the order in which the system tries to boot from each device.

• You may need to change this order: Make sure the BIOS is set up to try booting first from the device you are using.

Requirements

• CMOS: is the persistent memory that stores system configuration information.

• To change the BIOS setup, you need to edit the information stored in CMOS.

Interfaces: Installer and Installed System

• A textual interface, also called a command-line interface (CLI) or character-based interface, displays characters and some simple graphical symbols.

• It is line oriented; you give it instructions using a keyboard only.

Interfaces: Installer and Installed System

• A pseudographical interface, sometimes referred to as a textual user interface (TUI).

• Takes advantage of graphical elements on a text-based display device such as a terminal.

• It may also use color. This interface uses text elements, including simple graphical symbols, to draw rudimentary boxes that emulate GUI windows and buttons.

• The TAB key frequently moves the cursor from one element to the next and the RETURN or SPACE key selects the element the cursor is on; you give it instructions using a keyboard only.

Interfaces: Installer and Installed System

• A graphical user interface (GUI) typically displays a desktop (such as GNOME or KDE) and windows; you give it instructions using a mouse and keyboard.

• You can run a textual interface within a GUI by opening a terminal emulator window.

• A GUI uses more computer resources (CPU time and memory) than a textual interface does.

Interfaces: Installer and Installed System

• Installer interface: Fedora/RHEL provides a user-friendly, graphical installer interface and an efficient, pseudographical installer interface.

• Both interfaces accomplish the same task: They enable you to tell the installer how you want it to configure Fedora/RHEL.

• The pseudographical interface gives you fewer choices.

Fedora or Red Hat Enterprise Linux?

Fedora• The Fedora Project is sponsored by Red Hat and

supported by the open-source community.• Fedora Linux distribution incorporates cutting-edge

code.• It is not recommended for production environments

where the set of software packages and features must remain constant over a longer period of time.

• It is widely regarded as the most stable “free” Linux distribution.

Fedora or Red Hat Enterprise Linux?

RHEL• It is more stable but less cutting edge than Fedora. RHEL

provides at least 7 years of updates; Fedora provides 13 months.

• Red Hat Enterprise Linux and Red Hat Enterprise Linux Advanced Platform function identically and are designed to run servers.

• Red Hat Enterprise Linux is licensed for systems with one or two physical CPU chips and up to four virtual guests.

• Red Hat Enterprise Linux Advanced is licensed for systems with any number of CPU chips and virtual guests.

Upgrading an Existing Fedora/RHEL System

• An upgrade replaces the Linux kernel and utilities on an already-installed version of Fedora/RHEL with newer versions.

• During an upgrade, the installation program attempts to preserve both system and user data files.

• An upgrade brings utilities that are present in the old version up-to-date but does not install new utilities except as needed to satisfy dependencies (you can install them later if you like).

• Existing, modified configuration files are preserved; new ones are added with a .rpmnew filename extension.

• A log of the upgrade is kept in /root/upgrade.log.

Upgrading an Existing Fedora/RHEL System

• Clean install: An installation writes all fresh data to a hard disk.

• The installation program overwrites all system programs and data as well as the kernel.

• You can preserve some user data during an installation depending on where it is located and how you format/partition the hard disk.

Setting Up the Hard Disk

• Low-level formatting is the first step in preparing a disk for use (this is done at the factory.)

• Second, write a partition table to it and to create partitions on the disk.

• Finally, you need to create file systems on the partitions. The area of the disk not occupied by partitions is called free space.

• Under DOS/Windows, the term formatting means creating a filesystem on a partition.

Setting Up the Hard Disk

• A partition, or slice, is a logical section of a hard disk that has a device name, such as /dev/sda1, so you can refer to it separately from other sections.

• For normal use, you must create at least one partition on a hard disk.

• After you install Fedora/RHEL, you can use the palimpsest disk utility to view, resize, and create partitions on an existing system.

Setting Up the Hard Disk

• A partition table holds information about the partitions on a hard disk.

• Before the first partition can be created on a disk, the program creating the partition must set up an empty partition table on the disk.

• As partitions are added, removed, and modified, information about these changes is recorded in the partition table.

• If you remove the partition table, you can no longer access information on the disk except by extraordinary means.

Setting Up the Hard Disk

• Filesystem: Before most programs can write to a partition, a data structure, called a filesystem, needs to be written to the partition.

• This data structure holds inodes that map locations on the disk that store files to the names of the files.

• When the Fedora/RHEL installer creates a partition, it also automatically writes a filesystem to the partition.

• You can use the mkfs (make filesystem) utility, which is similar to the DOS/Windows format utility, to manually create a filesystem on a partition.

The Linux Filesystem

Setting Up the Hard Disk

Primary, Extended, and Logical Partitions• You can divide a disk into a maximum of 15

partitions.• You can use each partition independently for

swap devices, filesystems, databases, other resources, and even other operating systems.

• At most, a disk can hold four primary partitions.• You can divide one (and only one) of these

primary partitions into multiple logical partitions• This divided primary partition is called an

extended partition.

Setting Up the Hard Disk

• Absolute pathnames: All files on a Linux system, including directories, have a unique identifier called an absolute pathname.

• An absolute pathname traces a path through the directory hierarchy starting at the root directory and ending at the file or directory identified by the pathname.

Setting Up the Hard Disk

• Mounting Point: • A filesystem on a partition holds no information

about where it will be mounted in the directory hierarchy.

• You can mount a filesystem on any directory in the directory hierarchy (in installation process).

• The directory that you mount a filesystem on is called a mount point.