Unix Administration 1

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ITI-481 – UNIX ADMIN Chris Uriarte, Instructor

ITI-481: Unix AdministrationRutgers University Internet Institute

Instructor: Chris Uriarte

<[email protected]>

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Meeting Times and Locations

Per Syllabus

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Prerequisites

• Either ITI-480 Unix Fundamentals or equivalent user-level knowledge of Unix.

• You MUST know how to use a UNIX text editor (i.e. pico, vi, emacs)

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Course Overview and Goals

• The purpose of this course is to teach you how to install a UNIX operating system and perform system administration activities in a hands-on environment.

• The course objective will be achieved through a combination of lecture, demonstrations, and hands-on exercises.

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Major Topics

• Installing UNIX and Linux• X-Window Configuration • Installing Software • Account Management • Booting and Shutting Down• Network Configuration• Core System Services• System Monitoring and Logging• File System Administration • Configuring Specific Services: NIS, SSH, Sendmail,Telnet, FTP,

Printing• Securing your Server

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Course Resources

• Textbook: To be announced• Instructor Website at

http://www.cju.com/classes/ (see link to ITI 481 at bottom of page)

• Workstation where each of you will install a copy of Linux.

• User account on Linux server iti.rutgers.edu.

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Today’s Agenda

• Introduction to UNIX, UNIX distributions and some background concepts.

• Installing Linux on your own workstation.

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What is UNIX

• UNIX is an operating system that originated at Bell Labs (NJ) in 1969.

• UNIX is actually a trademark, but often used as a generic term to describe “UNIX-like” operating systems.

• There are numerous different flavors of UNIX – all of which utilize similar UNIX operating system concepts, but may have different features or run on different hardware.

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The UNIX Umbrella

RedHat, Mandrake†, SuSe, Debian, Caldera,

Yellowdog†

FreeBSD, BSDI*, NetBSD OpenBSD

Sun Solaris, HP HP-UX*, Compaq True 64 UNIX*,

IBM AIX*, IRIX*, MAC OSX*

SCO UNIX (now Caldera/Tarantula)

Hardware Vendors

BSD Flavors

Linux Distributions

Other

* = Commercial distribution (i.e you must pay for it)

† = Derivative of RedHat

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Popularity vs. MaturityPopular

Mature

Sun Solaris

HP-UX

Compaq True 64 UNIX

RedHat Linux / Linux Mandrake

Debian Linux

SuSe

Caldera Linux

FreeBSD / NetBSD / OpenBSD, etc.

SCO UNIX

RedHat Linux

AIX

IrixDarwin (Mac OSX)

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What makes UNIX Unique?

• UNIX is a multi-user, time-sharing operating system: every user gets a piece of the CPU.

• UNIX flavors generally adhere to some types of standards (I.e. POSIX)

• UNIX standards allow for portability of software across multiple UNIX distributions.

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What is Linux?

• A Unix-like operating system initially developed in the early 1990s by Linus Torvold.

• Initially developed to run on PC hardware but has been ported to other architectures as well.

• Distributed under a GNU General Public License – “free” software.

• Kernel is its distinguishing feature.• Generally packaged in various distributions.

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Linux Distributions

• Vary according to included software packages, package management systems, installation process, and Window Managers.

• Distributions– Red Hat Linux– Caldera OpenLInux– Linux Mandrake– Corel Linux– SuSE Linux– TurboLinux– Debian GNU/Linux– Slackware

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Why Linux?• Linux has matured greatly over the past 5 years and has

positioned itself as the most flexible UNIX distribution today.• It can be run on very low-end, generally available hardware.• Lots of software available.• Flexible – the same Linux distribution used by a hobbyist on low

end hardware can be used by an enterprise on high-end hardware.

• It’s the first UNIX flavor to hit retail store shelves and is easily obtainable across the world.

• Administration skill sets transfer easily to and from other UNIX flavors.

• It’s free!

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Planning for Your Linux System

• Is your hardware supported?

• Will it be a workstation or a server?

• Are there special services that you want to run (web server, email server, DNS server, etc.)

• Will you need to store user and/or application data?

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Checking Hardware Compatibility

• It’s very important that you make sure you hardware is fully supported by your UNIX distribution.

• Hardware Compatibility Lists (HCLs) contain the hardware supported by your OS vendor. They can be obtained at the vendor’s website.

• Therefore, it’s good to know some specifics about the hardware you’re using: amount of system RAM, brand of video card, brand of NIC brand of sound card, etc.

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Hardware Compatibility, con’t.

• Some particularly good things to know about your hardware:– Video card: brand and chipset– Hard drive: total amount of hard drive space– Sound card: brand and model of sound card– Network Card: brand and model of NIC

• Some vendors have searchable hardware compatibility database– RedHat: http://www.redhat

.com/support/hardware/

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Disk Partitioning• Disk Partitioning is the concept of dividing

your hard disk into logical partiations, making one hard drive appear as if it’s actually multiple drives.

• There’s several reasons why we partition disks:– Performance– Ease of storage management– Security

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UNIX Disk Partitioning• In UNIX, a physical disk partition is

associated with a directory path, sometimes referred to as a mount point.

• All files that are in directories associated with a mount point are stored on the mount point’s physical partition.

• If a directory path is not explicitly associated with a physical disk partition, its files are stored under the root ( “/” ) partition.

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UNIX Partition Example

/usr

2GB

/ (root)

1.5GB

/home

4GB

swap

Example Partitioning Scheme:

Total Hard Drive Space: 8GB

Contains all files under the /usr directory (I.e.

/usr/local/bin/pico, /usr/bin/vi, etc.)

Contains all files under the /home directors (I.e.

/home/chrisjur, /home/iti1234)

Contains all other files and directors, such

as /var, /opt, /sbin, etc.

[HARD DRIVE]

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Partition Naming• In UNIX, the system gives each partition a special device

name.• In Linux, standard IDE hard drives are named /dev/hdx,

where x is a unique letter given to identify the hard drive, starting with the letter a (e.g. /dev/hda)– For example, the first hard drive on the system is

called /dev/hda.• Partitions are given a name with the format /dev/hdx# ,

where /dev/hdx is the hard drive the partition is on, and # is a uniquely assigned partition number, starting with 1 (e.g. /dev/hda1). – For example, the first partition on the first hard drive on

the system is called /dev/hda1.

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Figuring out Your Partitions• You will have to partition your disk during a

typical UNIX installation.• Common partitions include: / (called ‘root’), /usr, /home, /var• Typical uses for specific UNIX partitions:

– /usr – software packages– /home – user home directories– /var – log files and configuration files– /opt – software package and application installed

(esp. on Solaris)

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What do you need to Install UNIX?

• At minimum, you need a CD media containing the UNIX distribution.

• You may be able to set your computer to boot directly from the CD-ROM, which will start the install program.

• If your computer cannot boot directly from the CD-ROM, you must create a boot floppy disk, which will boot the computer and load the installation program from CD-ROM.

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Exercise: Installing Linux On Your Workstations• Refer to the distributed instructions.

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Note: Linux and Other Operating Systems on a Single PC• Yes, Linux can run on a PC that is running one or more other

operating systems. However, there are a number of caveats:– Linux needs to be installed after Microsoft operating systems.

– You need to have unused partitions on your existing PC hard drive to install Linux.

– Linux needs to be installed on one or more of its own partitions. The kernel needs to be on a primary partition.

– Multi-booting is not recommended for servers.

• Recommendation: If you really want to dual-boot Linux with another operating system, use a commercial software package like PartitionMagic and BootMagic (by PowerQuest)

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Homework

• Homework this week:– As noted in class

• Next week:– Introduction to the X-Windows system– Software installation– Booting and Shutdown– Emergency boot procedures

Technology

Unix Administration 1