LTSP By Hector Gonzalez. LTSP LTSP stands for Linux Terminal Server Project. LTSP is an package for Linux that allows you to connect lots of low-powered.

LTSPLTSP

By Hector GonzalezBy Hector Gonzalez

LTSPLTSP

LTSP stands for Linux Terminal Server Project. LTSP is an package for Linux that allows you to

connect lots of low-powered thin client terminals to a Linux server. Applications typically run on the server, and accept input and display their output on the thin client display.

Software and documentation is provided in www.ltsp.org

Last version released LTSP-4.2

LTSP conceptLTSP concept

What is needed?What is needed?

A powerful server. A few low-power clients. PCs or

workstations. Network equipment. The server software (the client software is

contained in the server) The server is running his own operating

system (Fedora, for example).

What are the benefits of LTSP?What are the benefits of LTSP?

Save money– Software licenses.– Powerful clients.

Save time– You do not need to configure each workstation, only

the boot configuration, because all the configuration is in the server.

– If you have a PC, you have to set up updates, firewalls, install new applications ...

Open source– LTSP provides documentation, you can learn about

Linux configuration and networking while you are implementing LTSP.

What are the withdrawals of What are the withdrawals of LTSP?LTSP?

Your server OS must be Linux.– Mostly all distributions are supported.

Your client OS is going to be Linux. You have to setup the server

– Linux configuration could be confusing. Only Linux applications can run.

– But you could use a Windows emulator (WINE). Linux environment

– Not everybody knows how to work in a Linux environment.

– Less friendly environment than windows.

Server requirements exampleServer requirements example

Disk space– Besides the OS you need about 100 MB for the LTSP software.– User data.

Example: 25 users, 5 GB per user => 125 GB

RAM– 4GB of RAM, 50 workstations.

Processors– Pentium 4, 2.4 GHZ, 50 workstations.

Ethernet NIC– Linux compatibility.

Other hardware attached to the server– Printers, CD/DVDs writers.

Client hardwareClient hardware

Low-powered computers.– Low processor capabilities, low RAM, low

hard disk or even without hard disk.– A 90MHz Pentium with 16MB RAM is a good

one.

– It is possible to start a computer without hard disk.

Workstations.– LTSP.org provides a list of tested

workstations [see].

Workstation exampleWorkstation example

LTSP Term 140 200 MHz processor 64 MB ram 1280x1024 at 16 bit

colour video resolution Requires LTSP v4.1 Boots via PXE Price $224.95

Other solutionsOther solutions Traditional Windows PC

– PCs are too expensive.– Expensive to maintain. 35 workstations would require at least 1

full-time system administrator.– License management problems.– Proprietary solution depending on vendor.– Future software upgrades mean upgrading ALL desktops.

Windows Based Terminal– Based on Microsoft Windows– Proprietary solution depending on vendor– Expensive Per-User licensing

Full PC based on Linux– Lower initial cost than option the options above– Too much hardware at each desktop. No need for the Hard drive,

CDRom or Floppy.– Expensive to maintain. A workstation failure would result in

downtime for the user.downtime for the user.

How much can you save?How much can you save?

Cost comparison for 35 computers

Workstation

Windows PCs

Old used PCs

0

5000

10000

15000

20000

25000

30000

$28,000 $7,875 $1,750

*DELL OptiPlex *Term 140 *Pentium I or II

InstallationInstallation

There are three phases to building an LTSP server:– Installing the LTSP utilities– Installing the LTSP client packages– Configuring the services needed by LTSP

Installing the LTSP utilitiesInstalling the LTSP utilities

Includes utilities for installing and managing the LTSP client packages, and for configuring the services on the LTSP server.

The last version is LTSP 4-2. Availability in several formats

– tgz, rpm, dev About 40KB. You can download the rpm version from

– http://ltsp.mirrors.tds.net/pub/ltsp/utils/ltsp-utils-0.25-0.noarch.rpm

Other formats can be found in:– http://www.ltsp.org/download/

Install the package:– rpm -ivh ltsp-utils-0.25-0.noarch.rpm

Installing the LTSP client Installing the LTSP client packagespackages

Run the “ltspadmin” command in a shell. You will see the administration window. Choose "Install/Update" option to install the

packages.

Installing the LTSP client Installing the LTSP client packages (2)packages (2)

The LTSP Installer configuration window will appear.

Installing the LTSP client Installing the LTSP client packages (3)packages (3)

The options that you have are:– Select the source of the packages.

If your computer is connected to Internet type http://ltsp.mirrors.tds.net/pub/ltsp/ltsp-4.2/

Else you have to download the files and save them in a file. For the LTSP 4-1 version and below you can download the ISO file and burn it into a CD (http://sourceforge.net/project/showfiles.php?group_id=17723). After you have to specify your source, for example file:///media/cdrecorder if is a CD.

– Directory of the client tree. Accept the default value

– Http proxy URL. If your connections go through one, specify the URL. Otherwise

accept the default options

– FTP proxy. The same than before.

Installing the LTSP client Installing the LTSP client packages (4)packages (4)

Press “a” to select all components and “q” to install them.

Configuring the services needed Configuring the services needed by LTSPby LTSP

LTSP relys on 4 services:– DHCP [Dynamic Host Configuration Protocol]: used to

lease IPs to clients.– TFTP [Trivial Transfer File Protocol]: to transfer files to

clients, like the client software.– NFS [Network File System]: used to mount remote

directories.– XDMCP [X Display Manager Controller Protocol]: used to

implement graphical login displays.

Configuring the services needed Configuring the services needed by LTSP (2)by LTSP (2)

Type “ltspcfg”. That are the options you have to configure:

Configuring the services needed Configuring the services needed by LTSP (3)by LTSP (3)

Runlevel– Select runlevel 5 to indicate that your system is in

graphical mode in a network.

Interface selection– Select the current NIC

DHCP– It will create a default dhcpd.conf file and run the service.

TFTP– Enable the service

Portmapper– Used by RPC services, such as NFS

Configuring the services needed Configuring the services needed by LTSP (4)by LTSP (4)

NFS– It will create the default configuration file and start the

service. XDMCP

– Allow graphical logins in the client. Enable it. Create /etc/hosts entries

– Some services like NFS need to be able to map the IP of a workstation to a host name. Create the entries.

Create /etc/host.allow entries– This file provides security. Create it.

Create the /etc/exports file– This file is used by NFS to determine which directories

are allowed to be mounted by remote machines. Create it.

Configuring the services needed Configuring the services needed by LTSP (5)by LTSP (5)

Create the lts.conf file– The configuration of each workstation is in this file.

Type “ltspcfg” and “s” to check the configuration.

Workstation specific configurationWorkstation specific configuration

For your specific network there are 3 files you need to edit.– /etc/dhcpd.conf

For the DHCP service.

– /etc/hosts For the name/IP address mapping.

– /opt/ltsp/i386/etc/lts.conf Specific configuration of the workstation.

The explanation of how to edit /etc/dhcpd.conf and /etc/hosts goes beyond this paper.

Workstation specific configuration Workstation specific configuration (2)(2)

The file /opt/ltsp/i386/etc/lts.conf includes a default configuration for the clients.

[Default] SERVER = 192.168.0.254 XSERVER = auto X_MOUSE_PROTOCOL = "PS/2" X_MOUSE_DEVICE = "/dev/psaux" X_MOUSE_RESOLUTION = 400 X_MOUSE_BUTTONS = 3 USE_XFS = N LOCAL_APPS = N RUNLEVEL = 5

Workstation specific configuration Workstation specific configuration (3)(3)

Use the default values but “SERVER”, specify your server IP address.

Booting workstationsBooting workstations

Set up the workstations to boot up.– Hard disk– CD– Floppy disk– Network Interface Card

Technologies– PXE [Pre-boot eXecution Environment]– Etherboot

Booting technologiesBooting technologies

PXE [Pre-boot eXecution Environment]– Allows you to boot a computer without hard

disk or floppy disk or CD.– It boots from network.

You need a NIC.

– It is a feature available in most NICs.– You have to enable PXE in the BIOS setup– This is the process:

Send DHCP requests. Get IP. Get the boot file.

Booting technologies (2)Booting technologies (2)

Etherboot– A boot image is required for starting the boot

process.– You create a boot image in a CD or floppy disk.

Set up the BIOS to boot from CD/floppy disk. http://www.Rom-O-Matic.net/

– You also can create the boot image in the NIC The boot program is written in an EPROM memory. The EPROM is inserted in a socket in the NIC. Set up the BIOS to boot from a LAN. http://www.Rom-O-Matic.net/

MotivationMotivation

The idea of processing all the tasks in the servers is a new concept.

It can be used in a lot of environments, for example in cyber-cafes, universities, virtual kiosks, terminal access...

You can do it at home by yourself. It does not necessarily requires a lot of money. It is a Linux technology. Nowadays a lot of

companies, governments are moving to Linux. I have seen this before but I did not know the

technology underlying.

Future worksFuture works

Problems configuring the DHCP service in Fedora.

Install WINE or any other Windows emulator to provide Windows applications use.

Find a source with the hardware required in the server according to the applications running/number of clients.

Escalate the number of servers.

ProblemsProblems

I downloaded the DHCP service from I downloaded the DHCP service from ftp://download.fedora.redhat.com/pub/fedora/linux/ftp://download.fedora.redhat.com/pub/fedora/linux/core/updates/2/SRPMS/dhcp-3.0.1rc14-1.src.rpmcore/updates/2/SRPMS/dhcp-3.0.1rc14-1.src.rpm

I installed it and could have the service installed I installed it and could have the service installed and enabled, but not running.and enabled, but not running.

I tried to start the service manually with “service I tried to start the service manually with “service dhcpd start”, but I got error message. Actually I got dhcpd start”, but I got error message. Actually I got [failed].[failed].

I tried uninstalling and downloading packages, but I tried uninstalling and downloading packages, but the result was the same.the result was the same.

I used sample configuration files, with the real I used sample configuration files, with the real parameters of the network, but it did not work.parameters of the network, but it did not work.

Problems 2Problems 2

I checked online several times and I did not find I checked online several times and I did not find any explanation to the problem.any explanation to the problem.

I installed the LTSP and DHCP server in other I installed the LTSP and DHCP server in other computer without the Linux configuration done in computer without the Linux configuration done in the labs and I got the same problems.the labs and I got the same problems.

I had into account the fact of the server had 2 NIC I had into account the fact of the server had 2 NIC cards and maybe it could create conflicts ?, but I cards and maybe it could create conflicts ?, but I did not find any relevant. did not find any relevant.

I do not know what is the problem.I do not know what is the problem. I considered the idea of installing another I considered the idea of installing another

distribution, but I did not for reasons of time.distribution, but I did not for reasons of time.

Problems 3Problems 3

In that point I gave up with the DHCP In that point I gave up with the DHCP configuration.configuration.

The ROM for booting the remote computers The ROM for booting the remote computers was online in www.rom-o-matic.net , but was online in www.rom-o-matic.net , but without the DHCP service enabled, the without the DHCP service enabled, the client did not work.client did not work.

ConclusionConclusion

Remote execution of process is an interesting concept with a lot of applications in the real life.

You can save money in hardware and in licenses. Linux configuration can be tough but

documentation is provided by www.ltsp.org. Other solutions are either inefficient or more

expensive. The the LTSP software provides an administrator

tool for installing/monitoring the software. Computers without hard disk can be booted from

a server using either PXE or Etherboot.

ResourcesResources

www.ltsp.org www.disklessworkstations.com www.Rom-O-Matic.net www.google.com Linux Toys 2