Book Image

Nagios Core Administration Cookbook - Second Edition

By : Tom Ryder
Book Image

Nagios Core Administration Cookbook - Second Edition

By: Tom Ryder

Overview of this book

Nagios Core is an open source monitoring framework suitable for any network that ensures both internal and customer-facing services are running correctly and manages notification and reporting behavior to diagnose and fix outages promptly. It allows very fine configuration of exactly when, where, what, and how to check network services to meet both the uptime goals of your network and systems team and the needs of your users. This book shows system and network administrators how to use Nagios Core to its fullest as a monitoring framework for checks on any kind of network services, from the smallest home network to much larger production multi-site services. You will discover that Nagios Core is capable of doing much more than pinging a host or to see whether websites respond. The recipes in this book will demonstrate how to leverage Nagios Core's advanced configuration, scripting hooks, reports, data retrieval, and extensibility to integrate it with your existing systems, and to make it the rock-solid center of your network monitoring world.
Table of Contents (18 chapters)
Nagios Core Administration Cookbook Second Edition
About the Author
About the Reviewer

Establishing a host dependency

In this recipe, you'll learn how to establish a host dependency between two hosts. This feature can be used to control how Nagios Core checks hosts and notifies them about problems in situations where if one host is DOWN, it implies that at least one other host is necessarily DOWN.

Getting ready

First of all, it's very important to note that this is not quite the same thing as a host being UNREACHABLE, which is what the parents directive is for, as discussed in the Creating a network host hierarchy recipe in this chapter. Most of the time, a host actually being DOWN does not mean that other hosts actually go DOWN by definition. It's more typical for a child host to simply be UNREACHABLE; it might work fine, but Nagios Core can't verify this because of the DOWN host in its path.

However, there's one particularly broad category where host dependencies are definitely useful: the host/guest relationship of virtual machines. If you monitor both a host physical machine...