One way to gain a better understanding of Nagios—an open-source host and service monitor and the foundation for GroundWork Open Sources GroundWork Monitor Professional—is to download a copy of the tool at www.nagios.org and try it out. Helpful in guiding users through the Nagios tool is a book that eWEEK Labs got an early look at: "Nagios: System and Network Monitoring."
In the $44.95 book, which is published by No Starch Press and expected to be available by the time this review appears in print, author Wolfgang Barth has done a good job of documenting Nagios configuration parameters.
The real strength of this beginners guide to Nagios, however, is in the tidbits of advice that are liberally sprinkled throughout its 447 pages. For example, on Page 195, Barth advises, "You should think hard about whether you set the warning limit in the NET-SNMP or in the Nagios configuration." He goes on to explain some timesaving options, such as querying the percentage load of the hard disk by checking each host individually and making a change in a plug-in that is used to check many hosts.
The introduction to the book not only sets the stage for the type of information to be found within the printed pages but also ably takes on the task of explaining just what Nagios is. The first 130 or so pages are devoted to explaining various basic monitors.
The book does not attempt to explain every plug-in currently available for Nagios, but it does go into enough depth on the most common plug-ins that IT managers should be able to extrapolate the information to others they are using in their organizations. The book also goes into some detail on writing plug-ins from scratch.
During our tests of GroundWork Monitor Professional 4.5, we used Barths book to help us understand and configure the products underlying Nagios components.
The Nagios tool has a good understanding of network topology, and network managers would do well to spend some time with Chapter 7. It details, for example, how Nagios avoids a problem associated with less intelligent management tools by determining dependencies in the network topology and reporting root-cause problems.
Although the documentation provided with GroundWork Monitor Professional 4.5 is well-written and comprehensive, "Nagios: System and Network Monitoring" gave us a greater understanding of how to test local resources. And the book was especially useful since there are several interface screens in GroundWork Monitor Professional 4.5 that are purely Nagios.
However, its important to note that Nagios 2.0 was released on Feb. 7, after the book went to print. The majority of concepts in the book apply to the new version of Nagios, and the book provides a link to updates and corrections (www.linux.swobspace.net/books/nagios).
The catch: The site is written in German. We hope an English-language translation is made available soon.