The Linux Terminal Server Project (LTSP) allows inexpensive thin client computers to connect to a server running Linux, distributing the server's processing power to multiple desktop clients over the network; it works by booting the thin clients from the server using PXE, NFS and NBD to access the server's filesystem and run applications remotely; the document provides information on installing, configuring and troubleshooting an LTSP server and thin clients.

1. LTSP
Linux Terminal Server Project
Raman.P
DBA
Railway Hospital,Ayanavaram,
Chennai 23
raamanp@yahoo.co.in

2. What is LTSP ?
The Linux Terminal Server Project
(LTSP) is a package added to Linux
that allows inexpensive thin client
computers to be connected to a
server, spreading the power of the
server to many desktops.
This slide is from Jim, creator of ltsp

3. How does it all work ?
This slide is from Jim, creator of ltsp

4. Workstation Boot Methods
● Etherboot boot floppy from Rom-o-matic.net
● Etherboot Bootrom
● PXE
● Wireless ltsp booting kernel from floppy
This slide is from Jim, creator of ltsp

5. Boot Sequence
Thin client LTSP Server
1 Send DHCP request
Receive request, send reply 2
with IP addr and name of
Send TFTP request for file to download
3 kernel
Receive request, starting
sending blocks of data 4
Start executing kernel,
initialize devices, run
5 /linuxrc, detect NIC, send
DHCP request for more info Receive request, send reply,
including IP addr and root- 6
path for the NFS/NBD
NFS/NBD mount filesystem.
7 /opt/ltsp/i386 then do a
Pivot root to make it the Grant the mount request,
root filesystem serve data via NFS/NBD
8
Run rc.sysinit, then, launch
9 SSH connection to
Receive the ssh request,
server,launch ldm -ltsp
display manager allow X via ssh. 10
This slide is from Jim, creator of ltsp

6. Installing LTSP 5

7. Installing LTSP 5
● apt-get install ltsp-server
● ltsp-build-client
● Configure dhcp entries

8. Configuring the Server
There are several services that need to be
configured on the server.
They are:
● DHCP
● TFTP
● NFS
● XDMCP( non ldm )

9. dhcpd.conf
subnet 192.168.1.0 netmask 255.255.255.0 {
#range 192.168.1.20 192.168.1.250;
option domain-name "example.com";
option domain-name-servers 192.168.1.1;
option broadcast-address 192.168.1.255;
option routers 192.168.1.1;
next-server 192.168.1.108;
option subnet-mask 255.255.255.0;
option root-path "/opt/ltsp/i386";
if substring( option vendor-class-identifier, 0, 9 ) = "PXEClient" {
filename "/ltsp/i386/pxelinux.0";
} else {
filename "/ltsp/i386/nbi.img";
}
}
group {
use-host-decl-names on;
option log-servers 192.168.1.254;
host spare{
hardware ethernet 00:11:11:5f:66:46;
fixed-address 192.168.1.8;
filename "/ltsp/i386/pxelinux.0";
}
}

10. Tftp configuration
/etc/xinetd.d/tftp:
service tftp
{
disable = no
socket_type = dgram
protocol = udp
wait = yes
user = root
server = /usr/sbin/in.tftpd
server_args = -s /tftpboot
}
/etc/inetd.conf:
tftp dgram udp wait nobody /usr/sbin/tcpd /usr/sbin/in.tftpd -s /tftpboot
/etc/init.d/tftpd-hpa
This slide is from Jim, creator of ltsp

11. NFS configuration
/etc/exports:
/opt/ltsp/i386 192.168.0.0/255.255.255.0(ro,no_root_squash,sync)
/var/opt/ltsp/swapfiles 192.168.0.0/255.255.255.0(rw,no_root_squash,async)
This slide is from Jim, creator of ltsp

12. XDMCP configuration?
The display manager must be configured to accept remote connections
xdm-config:
# DisplayManager.requestPort: 0
kdmrc:
[Xdmcp]
Enable=true
#Port=177
gdm.conf:
[xdmcp]
Enable=true
MaxSessions=100
.
.
.
[servers]
0=/usr/bin/X11/X
This slide is from Jim, creator of ltsp

13. Workstation Configuration
lts.conf
[Default]
SERVER = 192.168.0.254
X_MOUSE_PROTOCOL = "IMPS/2"
X_MOUSE_DEVICE = "/dev/psaux"
SCREEN_01 = startx
[ws001]
PRINTER_0_DEVICE = "/dev/lp0"
PRINTER_0_TYPE = "P"
[ws002]
USE_NFS_SWAP = Y
SWAPFILE_SIZE = 64m
SCREEN_01 = shell
[ws003]
XSERVER = ati
X_MODE_0 = 1600x1200
This slide is from Jim, creator of ltsp

14. Troubleshooting
● ltspcfg
● netstat -anp
● showmount -e
● /var/log/messages
● SCREEN_01 = shell
● rpcinfo -p localhost
● tcpdump & Ethereal

15. Our Experience
● Total Nodes: 47
● Average active users 15-18
● 2 LTSP server P4-1.5,2 GB RAM
● Network: Assorted 100MB to Gigabyte
Switch on cat5/cat6 utp cable

16. Our Experience
● Clients use WindowMaker as window
manager
● Single application users do not have
window manager
● Custom application on Perl/Tk
● Only few use OpenOffice,Browser
● Local Printing

17. Advantages - Clients
● Booting time
– under 30 secs on pxe clients Celeron/p3s
– 40-50 secs on P1/P2s
● Custom print program prints on local
printer, with choice to select printer.
● Roaming: Users can login anywhere in
the hospital

18. Advantage - Sysadmin
● Single point of software maintenance
● Clients are plug and play system i.e in
case of problem simply replace box, no
need to install anything.
● Central monitoring of activity
● Database server and LTSP server on
single switch increasing throughput
and reliability.

19. Cost advantage
● Saves money
– Lower cpu
– No HDD
– No FDD/CD-ROM
● Longer Lifetime.
– Today's server – tomorrow's node
● Saves environment
– Reduces e-waste

20. More Info
● www.LTSP.org
● ltsp_discuss mailing list
● IRC (#ltsp on irc.freenode.net)
● www.k12ltsp.org
● www.SkoleLinux.org
● etherboot.sourceforge.net
● www.rom-o-matic.net
● www.tldp.org/HOWTO/Diskless-HOWTO.html