Index

1. Linux Terminal Server Project

• so far we have examined and and the development model
• what about the future and integrating these ideas together?
• Linux Terminal Server Project started in 1999
  • thin clients on GNU/Linux
• take out cdrom, floppy, harddrive
• build low power silent computers with typical specification
  • mini itx board, onboard fast
  • screen, keyboard, mouse
  • (maybe add higher quality pci graphics card)
  • roughly £
• this is almost certainly an over specified machine and built with premium components
  • obviously another technique is to use old machines and remove the hard disk

2. Concept

• ease of configuration
  • one file /opt/ltsp/i386/etc/lts.conf which describes all client configurations
• includes, graphics, various kernel modules, mouse type, mouse buttons, server, ramdisk size, nfs server, extra config files if really necessary, sound

3. Resources

• by default everything a user runs, executes on the server
  • ideal in todays environment
  • multi core 64 bit server (Opteron Quad/Dual Core) with multiple processors
  • huge hard drive on server
  • protect server against physical attacks and networked attacks
• users sit at thin client and effectively log into server using say, KDM
  • someone unacquainted with LTSP will think they are logging in normally
• by default all applications run on the server
• Linux is very good at disk caching and code sharing
  • so good that the LTSP project estimates you need
  • 250MB ram for the first user and only 50MB ram for subsequent users
• so how many users can you support with 1GB ram?
  • what about 4GB ram?
• LTSP is used at a call center and the server is one high end Dell machine
  • it serves 170 members of staff who are typically running OpenOffice and FireFox
• ideal also for exhibitions which want to provide Internet access
  • configure the networking on the server and plug in 100 thin clients..

4. LTSP client initialisation

• the client is diskless, so it boots using either
  • network interface card boot
    • the preferred method
  • floppy disk
• all methods
  • first it runs the protocol to obtain the netmask, gateway, tftp server addresses
  • second using it downloads pxelinux.0
  • third it runs pxelinux.0 which downloads the linux kernel from the tftp server
  • fourth it runs the kernel and uses to download the root filesystem
• note it uses pxelinux.0 as the linux kernel is too large to fit into base memory
• it configures itself from the root filesystem and starts an X server which connects to an XDM server which provides a graphical login screen
• the XDM server is where the application programs are run
  • normally this should be a powerful machine
  • ie multiprocessor quad core Opteron

5. Example /etc/lts.conf file

• this file is located at: /opt/ltsp/i386/etc/lts.conf on the server

• [Default]
          SERVER             = 192.168.0.6
          XSERVER            = auto
          X_MOUSE_PROTOCOL    = "IMPS/2"
          X_MOUSE_DEVICE     = "/dev/psaux"
          X_MOUSE_RESOLUTION = 400
          X_MOUSE_BUTTONS    = 5
          X_ZAxisMapping     = "4 5"
          USE_XFS            = N
          SCREEN_01          = startx
          SCREEN_02          = shell
          X_COLOR_DEPTH      = 24
          SOUND              = Y
          LOCAL_DEVICE_01    = /dev/hdc:cdrom
          HOTPLUG            = Y

6. Sample of the /etc/dhcp3/dhcpd.conf file

• option domain-name "example.org";
  option domain-name-servers 192.168.0.1;
  
  default-lease-time 600;
  max-lease-time 7200;
  
  subnet 192.168.0.0 netmask 255.255.255.0 {
    range 192.168.0.21 192.168.0.200;
    option routers 192.168.0.1;
  }
  
  
  host miniitx {
    hardware ethernet 00:40:63:e0:4c:8d;
    option root-path "192.168.0.6:/opt/ltsp/i386" ;
    filename "/tftpboot/lts/2.6.9-ltsp-3/pxelinux.0";
    server-name "192.168.0.6";
    next-server 192.168.0.6 ;
  }

7. Sample of the /etc/exports file

• # /etc/exports: the access control list for filesystems
  #               which may be exported
  #               to NFS clients.  See exports(5).
  #
  # server dir    client addresses
  #
  /opt/ltsp/i386  192.168.0.0/255.255.255.0(rw,sync)

8. Background reading and listening

• please take a look at ltsp and try listening to linux-terminal-09-2005.ogg
• this ogg file is an edited version of a VoIP conference (the original had a huge non ltsp intro - waiting for someone to turn up..)

9. Film of LTSP client booting

• apologies for camera shake..
• boot
• login

10. Use of LTSP

• LTSP allows full X windows, so for example the KDE, GNOME desktop
• applications by default run on server
  • can run applications on client
• typically client side programs include
  • dvd player ( mplayer , xine )
  • VoIP applications ( kphone )
• small text editors ( vi )
• OpenOffice runs exceptionally well on the server
  • first instance takes 3 seconds to start
  • subsequent instances have an almost instant start up time
• over 50% of users are educational establishments
  • greater 100,000 users
• popular use is to keep a Windows 2003 server on the network
  • and provide users with kdesktop
  • users have access to both GNU/Linux and Windows
• use 30 boot floppy disks to convert a Windows lab into a GNU/Linux lab
  • provides schools, Universities with low risk experimentation with GNU/Linux
• LTSP is available in the Ubuntu distribution (Breezy Badger)
  • and Debian (Etch/Sarge)
  • LTSP is being placed into Fedora and should lead to Redhat
• IBM is using LTSP
• sites are using

11. LTSP overseas

• Mark Shuttleworth in South Africa has organised 80,000 clients in schools
• South Korea
• Brazil
  • Telecentos project: 6000 Cyber cafés which have 20 terminals each
  • 120,000 thin clients
• massive financial saving

Index

This document was produced using groff-1.19.