Introduction to Linux, part 2 or 3.

1. ACE Course CT01558
Linux Introduction
Linux Boot & Installation

2.  Booting Linux
 Distribution Selection
 Considerations on Installation
 Installation Options
 Basic administration
Linux#2 - Installation 2
Agenda
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3. Linux#2 - Installation 3
System Initialization
BIOS
Boot
loader
Kernel
& device
drivers
init services Login
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Running Linux System

4. Linux#2 - Installation 4
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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5. Linux#2 - Installation 5
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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6. Linux#2 - Installation 6
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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7. Linux#2 - Installation 7
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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8. Linux#2 - Installation 8
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” directoryPartial view
lib
System
libraries
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9.  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

10. 8/22/2013Linux#2 - Installation 10
Kernel Compiler Features

11. Linux#2 - Installation 11
Linux Distributions
Kernel
GNU
X
Other
Linux
Operating
System
Red
Hat
Mint
Ubuntu
Others
+
+
+
+
Installation tools,
configuration tools,
SUPPORT, etc.
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12.  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
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Non Distribution Linux

13. Linux#2 - Installation 13
Linux Installation
 PRE
 Hardware Device Configuration
 Software Features
 Deployment Considerations
 Actual Installation
 POST
 Updating, security patches!
 Accounts, groups, services
 Maintenance
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14. Installing Linux: Hardware
Fedora 13 hardware requirements
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15. Sample pre-installation checklist
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16.  USB media
 DVD media
 FTP server
 HTTP Web server
 NFS server
 SMB server
 Packages on hard disk
16
Installing Linux: Installation Methods
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17. Linux#2 - Installation 17
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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18. Linux#2 - Installation 18
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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19. Linux#2 - Installation 19
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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20.  USB
 http://www.pendrivelinux.com/
 Virtual Machines
 Virtual Box http://www.virtualbox.com
 Vmware Player http://www.vmware.com
 CLOUD
 Amazon Web Services, Azure, …
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USB & Virtual Installs

21. Linux#2 - Installation 21
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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22. Linux#2 - Installation 22
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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23. Linux#2 - Installation 23
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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24. Linux#2 - Installation 24
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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25. Linux#2 - Installation 25
GUI User Mount Tool
 Run from “Applications”, “System
Tools”, “Disk Management.”
 Allows you to mount or dismount
drives or partitions.
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26. Linux#2 - Installation 26
Disk Partition Layout
M
B
R
Primary Extended Logical
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27. Linux#2 - Installation 27
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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28. Linux#2 - Installation 28
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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29. Linux#2 - Installation 29
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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30. Linux#2 - Installation 30
Controlling Services
 service ‘servicename’ function
 Function: start / stop / restart / status
 kill PID
 nice level process
 GUI: “System Tools”,
“System Monitor”
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31. Linux#2 - Installation 31
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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32. Linux#2 - Installation 32
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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33. Linux#2 - Installation 33
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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34. Linux#2 - Installation 34
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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35. Questions???

36.  Booting Linux
 Distribution Selection
 Considerations on Installation
 Installation Options
 Basic administration
Linux#2 - Installation 36
Summary
8/22/2013