LTSP on Ubuntu 8.04

LTSP Configuration for Ubuntu 8.10

Linux Terminal Server Project (LTSP) provides a way for you to build a server and then add diskless computers to the server thus creating a huge savings for an organization. To the user, they will not recognize that the computer they are at is without a hard drive. They typically notice the fast speed at which the workstation runs and the features that are available.

Notable Changes in LTSP 5
There are several significant changes in LTSP 5 which make the system much more usable. You will get enhanced security as now the GUI is exported using ssh -X and not the old XDMCP. SSH offers encryption of course which is actually faster and safer. The remote connection is made with LDM a python application that connects using SSH and not the old KDM or GDM. NFS has been dropped and replaced with NBD. NBD or Network Block Device is a network block device which emulates a block device like a hard drive over the network. This allows you to either use this space as swap or use it as network diskspace.

Related Links
LTSP Set Up on Ubuntu 8.10
LTSP Client
Managing Users in LTSP
Samba with LTSP on Ubuntu 8.10
Troubleshooting LTSP
UFW Firewall for LTSP

Advantages of LTSP

1. Cost – Diskless computers can be purchased new for about $200 and can be built from outdated computers for $0. This is a very interesting way to build a network from computers that others want to discard.
2. Central Management – Central Management alone will save an organization dramatically. You can expect virtually NO WORKSTATION maintenance with LTSP. Without a hard drive there is nothing to maintain except connections for monitor, network, keyboard and mouse. All management is done from the server.
3. Heat Reduction – Computers create heat which leads to more power usage to reduce the heat. Many diskless systems are only using 15 watts of power and producing virtually not heat.
4. Power Reduction – Diskless computers may use as little as 15 watts of power compared to the 450 watts of a typical workstation. When you are looking at 200 computers in a school system is a significant savings.
5. Flexibility – You are not limited to just running diskless computers. You can set up a network that will allow diskless computers, computers with disks and Windows computers connecting via Samba. One server can do it all for you.

Disadvantages of LTSP
1. Single Location of Failure – Since the whole network depends on the server up 24/7 that server must be robust and dependable. If the server is down everyone on the LTSP server is off line. You can create redundancy. It is simple enough to rsync two servers so that you have a clone ready to go if you experience failure. Having run LTSP for 8 years, I have never experienced a downtime longer than an hour.
2. Server Cost – You must invest in a server that is robust, something in the line of dual Xeons with 4-6 GB of RAM if you have upward of 100 diskless computers connected.

Setting UP LTSP 5 on Ubuntu 8.04

When you set up LTSP on Ubuntu 8.04 you will notice that it is very easy to get going in LTSP 5. Most of the configuration is automatically done for you. Install the Ubuntu 8.04.1 Desktop CD. You must have a graphical interface running on the server to be provided for the clients. Once you have installed the Desktop, be sure your network is set to operate on a static IP Address. Next you will need to install several programs required for the ltsp setup.

sudo apt-get install ltsp-server-standalone openssh-server

Create your Thin Client environment on the server with this command:

sudo ltsp-build-client

Update the Desktop System

sudo apt-get update

sudo apt-get upgrade

Configure DHCP
You will supply IP Addresses to the thin clients using DHCP. The file you want to edit is /etc/ltsp/dhcpd.conf. Note this is not the normal dhcpd.conf file that you would edit, this is a special file for LTSP only.

Here is a partial example file. The first line ensures that clients will use this DHCP server:

authoritative;

The subnet is declared with the network and netmask:

subnet 192.168.7.0 netmask 255.255.255.0 {

The next line which is indented is the range that your DHCP server will supply. So on this network example you could have static IP Addresses from 192.168.7.1-192.168.7.124 and then the range will define what dynamic IPs will be supplied by the DHCP server.

range 192.168.7.125 192.168.7.246;

It is a good idea to provide a DNS server for the clients:

option domain-name-servers 12.32.34.32;

Define the broadcast address:

option broadcast-address 192.168.7.255;

The optional router will also be the gateway for your network:

option routers 192.168.7.2;

Now you can set up individual diskless workstations. In these examples the hostname for the workstation is declared:

host ws205 {

Because you want to declare these hosts it is important that you modify your /etc/hosts file so the workstation is listed there. Here the workstation number is tied to the IP Address on the network so that it is easy to trouble shoot as you know right where to go to fix either a network problem or a hardware issue.
---cut---

ws202 192.168.7.202

ws203 192.168.7.203

ws205 192.168.7.205

ws206 192.168.7.206

---cut---

The hardware MAC address for each network card is listed so that you can tie the IP to a specific diskless workstation.

hardware ethernet 00:13:90:00:D7:8F;

The fixed IP Address is noted.

Fixed-address 192.168.7.205;

Finally a location to get the image for the diskless workstation is provided.

filename "/ltsp/i386/pxelinux.0";

That is the configuration for the clients as they will boot

#

# Default LTSP dhcpd.conf config file.

#

authoritative;

subnet 192.168.7.0 netmask 255.255.255.0 {

range 192.168.7.125 192.168.7.246;

option domain-name-servers 12.32.34.32;

option broadcast-address 192.168.7.255;

option routers 192.168.7.2;

host ws205 {

hardware ethernet 00:13:90:00:D7:8F;

fixed-address 192.168.7.205;

filename "/ltsp/i386/pxelinux.0";

}

host ws247 {

hardware ethernet 00:13:90:00:67:AF;

fixed-address 192.168.7.247;

filename "/ltsp/i386/pxelinux.0";

---cut---

When you have finished restart the server. Run these commands to update your ssh keys.

sudo ltsp-update-sshkeys
sudo ltsp-update-image

Be sure to do it in that order.

Diskless Workstations

There are many ways to set up the workstations. This example will show you how to set up a PXE bootable works. A diskless computer is a computer that does not have a hard drive so that the operating system is completely loaded over the network. The PXE bootable workstation locates a redirection service which is provided by your DHCP server. Once it make a connection to the DHCP server the firmware on the PXE rom requests the file path for the bootstrap program. The workstation then downloads the bootstrap program into RAM on the workstation using TFTP. The great thing about this system is that once it is set up it is all automatic.

Operating Software

PXE Network Booting LTSP Ready

CPU
1 GHz Via Eden V4 Processor (Fanless, x86 compatable)

Memory

256MB DDR SO-DIMM standard 512 MB max.

Display

CN700 with Integrated AGP 8x Graphics Core

Shared System memory 8MB to 64MB

Maximum resolution 1600 X 1200, 60 Hz refresh, 16-bit high color

800 x 600 / up to 85 Hz/ 32 Bit

1024 x 768 / up to 85 Hz/ 32 Bit

1280 x 1024 / up to 85 Hz/ 32 Bit

Networking

10/100 Base-T Realtek 8100C Fast Ethernet

I/O Connectors

Winbond W83697HF (LPC)

One serial port, RS-232C compatible,DB9M connector, baud up to 115.2K bps

One parallel port, DB25Fconnector, bi-directional centronics-compatible and locally printable

Analog VGA video output, DB-15 connector

Four USB 2.0 ports(two at front, two at rear) for floppy disk drive, mouse,CD-ROM, hard-drive, etc.

Two PS/2 ports for mouse and keyboard

RTL 8100C+ 10/100 Mbps, one RJ-45 connector

LED Indicators: . One Power indicator (On front bezel)

Two Network adapter indicators (On rear panel)

Warranty: . One year from date of invoice.

Power Supply: . External, autosensing

Input: 100-240V @ 50~60Hz

Dimensions (L X W X H): . 7.5" x 5.5" x 1.6", 190mm x 140mm x 40mm