Book Image

Learning Nagios - Third Edition

By : Wojciech Kocjan, Piotr Beltowski
Book Image

Learning Nagios - Third Edition

By: Wojciech Kocjan, Piotr Beltowski

Overview of this book

Nagios, a powerful and widely used IT monitoring and management software for problem -solving. It detects problems related to your organizations infrastructure and helps in resolving the issue before it impacts the business. Following the success of the previous edition, this book will continue to help you monitor the status of network devices and also notify the system administrators of network problems. Starting with the fundamentals, the book will teach you how to install and configure Nagios for your environment. The book helps you learn how to end downtimes, adding comments and generating reports using the built-in Web interface of Nagios. Moving on, you will be introduced to the third-party web interfaces and applications for checking the status and report specific information. As you progress further in Learning Nagios, you will focus on the standard set of Nagios plugins and also focus on teach you how to efficiently manage large configurations and using templates. Once you are up to speed with this, you will get to know the concept and working of notifications and events in Nagios. The book will then uncover the concept of passive check and shows how to use NRDP (Nagios Remote Data Processor). The focus then shifts to how Nagios checks can be run on remote machines and SNMP (Simple Network Management Protocol) can be used from Nagios. Lastly, the book will demonstrate how to extend Nagios by creating custom check commands, custom ways of notifying users and showing how passive checks and NRDP can be used to integrate your solutions with Nagios. By the end of the book, you will be a competent system administrator who could monitor mid-size businesses or even large scale enterprises.
Table of Contents (19 chapters)
Learning Nagios - Third Edition
About the Authors
About the Reviewer

Monitoring over SSH

Nagios is often used to monitor computer resources such as CPU utilization, memory, and disk space. One way in which this can be done is to connect over SSH and run a Nagios check plugin.

Automating the authentication process requires setting up SSH to authenticate using public keys. This works because the Nagios server has an SSH private key and the target machine is configured to allow users with that particular key to connect without prompting for a password.

Nagios offers a check_by_ssh plugin that takes the hostname and the actual command to run on the remote server. It then connects using SSH, runs the plugin, and returns both output and exit code from the actual check performed on the remote machine to Nagios running on the local server. Internally it runs the SSH client to connect to the server and runs the actual command to run along with its attributes on the target machine. After the check has been performed, the output along with the check command's exit code...