Transcript Linux & Library – Web Kiosks for Peanuts

Linux & Library – Web Kiosks
for Peanuts
Sam Deeljore
Pius XII Memorial/HSC Libraries
Saint Louis University
LITA 2004 National Forum
St. Louis, Missouri
Introduction
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Library needs
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Problems
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Replace aging text terminals
Provide web access to library catalogs in a
simplified kiosk interface
Lack of funds for new computer equipment
Windows is high maintenance
The Windows desktop UI is hard to control
Modern Windows requires powerful hardware
Linux provides the solution
Why Linux?
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No licensing costs
Stability matches or exceeds Windows
Good support for and better performance on
older PC hardware
The desktop is easy to control and
customize
Solutions for thin clients are readily available
Older hardware can be put back in service
Linux Thin Clients
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All the advantages of linux plus centralized
management
Applications run on the server and the
display is sent over the network to the thin
clients
Because the applications run on the server,
they run with all the speed of the server
Hard disks which are prone to failure are
eliminated with thin clients
Overview of our linux system
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Linux Terminal Server Project (LTSP)
software
1 server
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1.2 Ghz Pentium III with 1024 MB RAM
Holds all software including the terminals' OS
System load rarely exceeds 10%, 500MB RAM
used, no swapping
10 public web terminals
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166 Mhz Pentium I with 32 MB RAM
Terminals are diskless – no hard disk, no floppy
Terminals require a special chip for their network
cards to facilitate booting.
The Server Software
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Linux Terminal Server Project (LTSP)
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Http://www.ltsp.org
Packaged for most major Linux distributions
Open source
Provides the thin-client OS
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A stripped down version of linux
Busybox software provides all the command line
tools usually found in linux
Xfree86 – X windows system
The Chip That Makes It Happen
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The Boot ROM is inserted into a
socket on the ethernet card
Chips can be obtained from from
http://www.disklessworkstations.com
Uses Etherboot open source software,
available at
http://etherboot.sourceforge.net
A floppy loaded with etherboot can
perform the same tasks as the chip
Prices for the chip are $15-$18
depending on your NIC model
Etherboot – What the ROM does
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When machine boots, etherboot is loaded by
the BIOS before any device in the boot order
Etherboot requests an IP address, server IP
and filename from the DHCP server
Etherboot retrieves the file (the client's linux
kernel) using tftp
Etherboot boots the kernel it retrieved
The Web Browser
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Opera 7 for linux (http://opera.com)
Advantages
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Loads quickly, renders quickly
High-quality standards compliant rendering
Has an excellent kiosk mode
Disadvantage: Must buy a license to make
the banner ads go away
Opera Kiosk Mode
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Invoked by launching browser with certain
arguments as the Shell
Administrator can specify an idle time after
which the cache is emptied, history is
cleared, and the home page is reloaded
Administrator can hide print, save, and exit
menu choices
Administrator can lock browser in fullscreen
mode
See
www.opera.com/support/mastering/kiosk/
Getting Started
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Install your favorite linux on your server (we
use RedHat 9.0)
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The following server packages are needed: tftp,
dhcpd, and nfs.
XDM, KDM, or GDM are needed. We use gdm.
Squid may be installed as a proxy server to
accelerate web browsing and/or to restrict kiosks
to certain websites, such as your library catalog.
XFS (the Xwindow font server) may be installed
so that your server and your clients can share
fonts from a single directory (recommended)
Install the Software
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Install the LTSP packages
Install boot ROMs on your clients ethernet
cards, record the MAC addresses of each of
your client's ethernet card
Create/modify the following files:
/etc/dhcpd.conf - for dhcp requirements
/etc/hosts
- for access to the server
/opt/ltsp/i386/etc/lts.conf - for client
configuration
DHCP configuration
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Reserve an IP for each of your clients based
on their MAC. Additional parameters that
must be present for each client are
hostname, filename, and root-path.
If a dhcp server is already in place on the
network, it can be used with minor
modifications
Be very careful with DHCP
Configuring the Clients
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Basic settings are all done in the file
/opt/ltsp/i386/etc/lts.conf
Default setting applies to all hosts not
specifically defined
Set client runlevel, turn swap file on/off, set
size, choose custom X server settings
When a client boots it reads lts.conf and
dynamically creates all the configuration files
a linux machine needs (in temporary storage
in client RAM)
Linux Runlevels in LTSP
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Runlevel 3: for debugging – clients boots
and the user gets a shell as root
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Runlevel 4: telnet to a host in a loop with no
exit– set the telnet host to connect to in
lts.conf
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Runlevel 5: graphical login, display is
managed by the server
Desktop Security
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Opera kiosk mode
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Disable unwanted XDMCP sessions
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Enable timed login and autologin
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Disable remote root login
Network Security
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Firewall: iptables
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Tripewire Intrusion Detection System
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TCP Wrappers
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Keep current with patches
Beyond Web Kiosks
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Ideal desktop replacement for departments
which are not dependent on Windows desktop
or Windows only applications.
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What can users do on UNIX/LINUX?
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Email (Web Mail or Pop3/Imap)
Open Office/Star Office (MS office clones)
Web applications and telnet and ssh sessions
UNIX software development
Many users on one powerful server means
more efficient use of CPU cycles than many
users on many new powerful desktops.