Linux introduction Class 02

ACE Course CT01558 Linux Introduction

Linux Boot & Installation

Booting Linux

Distribution Selection

Considerations on Installation

Installation Options

Basic administration

Linux#2 - Installation 2

Agenda

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System Initialization

BIOS Boot

loader

Kernel

& device

drivers init services Login

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Running Linux System


BIOS Initialization

Power On Self Test recognizes hardware, CPU, memory, bootable configuration from CMOS

Bootable devices: CD ROM or Floppy

Drive [IDE, SCSI, SATA, RAID, SSD, SD, microSD, …]

Network

USB devices

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The Boot Loader

Last step in BIOS

Loads first partition of bootable device

It can present a menu of OS choices

Can also let you choose “Other OS”

Linux boot loaders:

LILO (Linux Loader) – older, static

GRUB (GRand Unified Bootloader) dynamic

Syslinux [for CDs and USBs]

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Kernel Initialization

Kernel loads based on parameters passed All logging goes to /var/log/dmesg

Detects hardware Loads initrd (if necessary)

Mounts root

Loads /lib/x.x.x/modules

Passes control to /sbin/init

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init (Initialization)

Init loads scripts from /etc/rc.d rc.sysinit is the master script at boot time

Loads networking, drivers, encryption, and provides [OK] or [FAIL] feedback

Based on parameter or /etc/inittab default, it will execute scripts in rc.x (x=runlevel)

All boot scripts live in init.d, can be configured via chkconfig

Last script is rc.local

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UNIX File System

tmp bin usr var etc dev

bin lib

/

local spool

Somewhere

for local

additions

Libraries,

some utilities

and config.

files

Spool files

for batch

utilities

Admin utilities

config. files

Special

device files Somewhere

everyone

can use

Utilities

System

programs

The top-level “root” directory Partial view

lib

System

libraries

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Pre-compiled kernels

The one downloaded in your distribution

The one you receive with system updates

Custom kernels

The ones you BUILD:

More security

Better performance

Hardware support or Virtualization

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Kernel Features


Kernel Compiler Features


Linux Distributions

Kernel

GNU

X

Other

Linux

Operating

System

Red

Hat

Mint

Ubuntu

Others

+

+

+

+

Installation tools,

configuration tools,

SUPPORT, etc.

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Mobile Linux http://en.wikipedia.org/wiki/Embedded_Linux

Game console Linux http://openpandora.org

Embedded Linux http://elinux.org

Automobile consoles & Google TV

Older hardware

Printers & Network equipment


Non Distribution Linux

http://en.wikipedia.org/wiki/Embedded_Linux



http://openpandora.org/

http://openpandora.org/

http://elinux.org/

http://elinux.org/


Linux Installation

PRE Hardware Device Configuration

Software Features

Deployment Considerations

Actual Installation

POST Updating, security patches!

Accounts, groups, services

Maintenance

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Installing Linux: Hardware

Fedora 13 hardware requirements


Sample pre-installation checklist


USB media

DVD media

FTP server

HTTP Web server

NFS server

SMB server

Packages on hard disk

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Installing Linux: Installation Methods

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Server Design Issues

Example: Server requirements are very diverse

Internet or intranet?

Which services are required?

Does it require user accounts?

Heavy or light usage?

No generic solution

Each server needs to be carefully designed

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H/W Compatibility & Resources

Supports a wide variety of CPUs & Architectures

Linux Hardware ‘How To’ at The Linux Documentation Project: www.tldp.org

Know your RAM & Disk requirements

Server, Desktop, Custom

http://www.tldp.org/HOWTO/Hardware-HOWTO

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Laptops

Tricky installations

Custom bus, Video and/or Sound chipsets

Older laptops may be difficult to install

Boot from CD, floppy or network

URL: www.linux-laptop.net

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USB

http://www.pendrivelinux.com/

Virtual Machines

Virtual Box http://www.virtualbox.com

Vmware Player http://www.vmware.com

CLOUD

Amazon Web Services, Azure, …


USB & Virtual Installs





http://www.virtualbox.com/

http://www.virtualbox.com/

http://www.vmware.com/

http://www.vmware.com/


Block Devices & Filesystem Schemes

/dev

Char & Block devices

Partitions: /dev/hda1… /dev/sda1…

Filesystem Hierarchy Standard (FHS) www.pathname.com/fhs

/ /etc /dev /lib/ /bin /boot /sbin

/usr /home /tmp /var /mnt /proc

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Removable Media

Mounting means making a foreign filesystem look like part of the main tree.

Before accessing, media must be mounted

Before removing, media must be unmounted

By default, non-root users may only mount certain devices (cd, dvd, floppy, usb, etc)

Mountpoints are usually under /media can also be defined in /etc/fstab

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Mounting CDs / DVDs

Automatically mounted in Gnome/KDE

Otherwise, must be manually mounted

CD/DVD Reader

mount /media/cdrom

CD/DVD Writer

mount /media/cdrecorder

eject command unmounts & ejects the disk

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Mounting USB Media

Detected by the kernel as SCSI devices: /dev/sdaX or /dev/sdbX or similar

Type: tail /var/log/messages to find out

Automatically mounted in Gnome/KDE

Icon created in Computer window

Mounted under /media/Device ID

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GUI User Mount Tool

Run from “Applications”, “System Tools”, “Disk Management.”

Allows you to mount or dismount drives or partitions.

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Disk Partition Layout

M

B

R

Primary Extended Logical

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Partitioning Hard Drives

GUI or text tools available during install

Auto or Manual modes

/boot partition

Dual boot systems

Swap partition (2x RAM)

Create LVM or RAIDs

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Virtual Consoles

Linux starts with 6 default virtual consoles

Alt-F1 to Alt-F6 (or CTRL <- ->)

Can have up to 63 consoles

Controlled from /etc/inittab

1:2345:respawn:/sbin/mingetty tty1

…

6:2345:respawn:/sbin/mingetty tty6

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System Shutdown and Reboot

To reboot: shutdown –r

reboot

init 6

To halt: shutdown –s

halt

init 0 You must be administrator!

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Controlling Services

service ‘servicename’ function

Function: start / stop / restart / status

kill PID

nice level process

GUI: “System Tools”, “System Monitor”

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Monitoring & Process Control

top – displays top processes uptime + ps = w ps ax – list of all running processes nice PID priority – changes priority level Default priority is 10, it can be changed from -20 (highest priority) to 19 (lowest)

kill –signal PID killall process

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Hands-on Lab-1

Exploring Linux Services

From command line type: top (press h, q after reading screens)

w [integrated who / uptime]

whoami

ps ax [list all active processes]

pstree

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Hands-on Lab-2

From command line type: su -

service http start

service http status

Or “ps ax | grep httpd”

killall httpd

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Hands-on Lab-3

From command line type: mount

To view default mounts: ‘more /etc/fstab’

df –h

du –sh /var

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Questions???

Booting Linux

Distribution Selection

Considerations on Installation

Installation Options

Basic administration


Summary

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Linux introduction Class 02

Software

Transcript of Linux introduction Class 02