October 2, 2006

DRBL: A quick and easy thin client server

Author: Frank Tuzi

Administrators interested in a cost-efficient, powerful, and easy-to-manage thin client server should consider Diskless Remote Boot in Linux (DRBL), a server-based open source application that lets organizations deploy GNU/Linux across many clients. DRBL lets clients boot a Linux image over the network, so client hard drives can retain their own operating systems, or clients can do without hard drives altogether.

We installed DRBL at my school, Tokyo Christian University (TCU), last year to replace an aging infrastructure of 15 Windows ME clients. These systems could not run a number of new applications, and users could not save any profile settings or store any documents in the system. Also, the system administrators only upgraded the labs between semesters because of the time involved. DRBL resolved all three of these problems.

To prepare for DRBL, we installed Fedora Core 5 on the server, along with office and educational software, graphics and multimedia applications, and administration and management tools. Once all of the applications were installed, we downloaded the DRBL RPM package, which installed application scripts in the server's /opt folder. Setting up the thin client/server system required only two commands: drblserv set up the server to function as a thin client server, and drblpush set up client folders, settings, and shared libraries.

DRBL includes startup options for clients. A system administrator can set clients to log on using the thin client system, or allow clients to boot their systems using their local hard drives, if the local drives have an existing operating system. The DRBL startup system also comes with Clonezilla, a disk imaging or partition backup system that lets administrators back up all of the client machines. Thus, DRBL can function as a client/server system, a dual boot chooser, and a disk imaging system.

The downside of system management is that these commands run from the command line; there is no X-based GUI.

Our new client computers originally did not have anything on the hard drives. To offer a backup in the event our server crashes, we decided to install Fedora Core 5 on the clients. We installed the operating system and several open source applications on one machine, then, using Clonezilla, we copied that one image to the DRBL server, and then copied the disk image to all the other new client computers. DRBL made the creation and distribution of the image a simple and fast process.

DRBL includes a variety of management tools that allow administrators to add, modify, and delete new client systems, copy files to each client or each user, and turn on and off services for clients. For example, we needed to activate the Japanese language input system for all students, regardless of what language users selected for their default language. Using the drbl-cp-user command, I copied the proper .xinput.d folder to each user. Later, we decided to turn on the system log on all the clients. Using the drbl-client-service command, administrators can turned on or off any service on any client. All of the commands come with help, and the DRBL Web site contains even more help.

The benefits of DRBL

The DRBL system has benefited us in a number of ways. DRBL centralized the management of our computer labs and allowed us to establish a primary domain where all users can authenticate their logons and store personal information. DRBL also enabled the university to easily offer to students new software like amaroK, Gaim, Inkscape, GnuCash, Stardict, and Streamtuner. One foreign exchange student asked for geographic information system software; once we installed the application, DRBL distributed it to all the client systems.

DRBL also enabled us to continue using hardware that otherwise would have become useless. Some of the hardware we own used to run Windows ME and 98. Windows XP is too resource-intensive for those systems, but they work just fine with the DRBL system.

While DRBL has given us more computer functionality than ever before, the system is not without its problems. However, when a problem has emerged, DRBL project members have been there to assist. Every time I requested assistance online at the project's Web site forums, I generally received answers within 24 hours. I also had the ability to chat online with DRBL staff and get help with DRBL and anything else Linux-related; the maintainers offered their IM ID in the forums after I posted a question. The repeated motto I hear from them is "I'll do my best."

DRBL rejuvenated our stagnant computer labs. After making the upgrades to the school lab system, the college, which began with a lab of 15 standalone computers, now has a networked lab of more than 40 computers using DRBL. All users now have personal profiles to store their GUI and application settings, as well storage locations for their personal files. DRBL allows the college to manage all client systems and all users with minimal effort from a single server. Upgrades to the system run virtually unnoticed while students take classes or work on their own projects in the lab.

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