One of the services that many public libraries provide is computer access, both for local applications and access to Internet services. The Wendell Free Library provides these services with thin1 Linux workstations. These workstations provide a web browser (Firefox), for access to web sites of all sorts and also provide a number of local applications, including an office suite (OpenOffice), plus several other applications, including a movie player (MPlayer), an image editing program (GIMP), and a large collection of games.
Using thin clients reduces energy costs, creates a uniform environment that only needs to be updated in one place, on the server, and quieter operation. This article describes the setup and configuration of these thin clients at the Wendell Free Library and covers the step-by-step process of setting up the server and the client machines and includes the process from installing the base system on the server to configuring the PXE boot process to user authentication and management.
7.1 Luma: Managing users and groups
7.2 PAM mkhomedir setting
8 Sendmail setup
9 Firewall, Routing, and IP Masquerading
10 CUPS Printer Sharing
User authentication is managed through OpenLDAP and slapd is run on the server. Extensive documentation on how to set up OpenLDAP and slapd and how to migrate to OpenLDAP exists on the CentOS and RedHat websites. A good place to start is on the CentOS web site: http://www.centos.org/docs/5/html/Deployment_Guide-en-US/ch-ldap.html.
I installed Luma (Version 2.4, built from source downloaded from SourceForge) to provide the librarian with an easy to use GUI program to manage user accounts. Most patrons will use the guest accounts provided, but a handful will want to have their own personal logins2. Luma is available from SourceForge: http://luma.sourceforge.net/.
I have enabled the PAM mkhomedir, so that new user’s will have the home directory automatically created.
I have set up Sendmail on the server as a mail hub for the diskless machines and configured Sendmail on the client machines to pass local delivery to the server. This avoids possible problems with file locking on the mail spool.
The server at the Wendell Free Library also acts as a router to the public Internet through a pair of HughesNet satellite dishes3 The server provides a fire wall and performs IP Masquerading between the local network and the public Internet.
The server also provides shared printer spools for the two wired network based printers. I set the cupsd.conf file on the server to “share” its printers with computers on the LAN and set up the clients to look for shared printers.
Next week will be the final installment and will talk about the MS-Windows PCs and the one thick Linux client machine.
*Copyright (C) 2009 Robert Heller.
1 Thin clients are diskless computers, which get their operating system and application software from a file server on the local area network (LAN).
2 I will attempt to encourage regular patrons to move towards having their own logins, as this enhances security and privacy and provides additional benefits including the ability to maintain a ’fully furnished’ home away from home.
3 We plan to be moving to a new Internet provider using a 900MHz wireless link provided by an adjacent town.