1. Adding Objects To Nagios 3.0
By: Mikhail Kniaziewicz

2. What is an Object in Nagios 3.0
Nagios has two types of objects
Host
Service
Nagios has object inheritance like Object Orientated Programming Languages.

3. Directory Structure of Nagios 3.0
$USER1$ is the default Nagios command directory. Four our system that is: /opt/nagios/libexec
Nagios global configuration files exist under /opt/nagios/etc
Object directories are broken down as follows under /opt/nagios/etc/objects: command, timeperiods, services, eventhandlers and contacts.

4. Process Flow for Nagios 3.0
The heart of Nagios is in the directory: /var/opt/nagios/.
When Nagios starts, restarts or reloads it reads all ”.cfg” files within the object directories.
The objects are stored within the object.cache file.
Current host and service statuses are stored in the status.dat file.
Logs for historical trending are stored under the archive directory.

5. Object Monitoring Objects are monitored using two methods
Active – Nagios request status
Passive – Client sends status when a change occurs
Nagios can monitor objects from two locations
Locally – On the Nagios server
Remotely – On the client using a daemon

6. Object Definition - Service
Basically, services are comprised from any action that is not directly related to defining a host.
Check a system's load average
Checking partition or directory size
Checking the number of users on a system
Pinging a host is not considered a service object but rather a host object.

7. Object Definition - Service
Send to System Monitoring so they know you are working with a new object definition.
Only work on objects during business hours to prevent alarming the World in the event you do not receive the desired results.
Check for existing templates and objects so you utilize Nagios' object inheritance feature.
Let EVERYONE in IT know about the object you created. Objects are created to benefit business functions and not one person.

8. Object Definition - Service
Define the service to be monitored
Check Nagios Exchange to see if a plugin already exists to monitor the service
If plugin is located, load the plugin into /opt/nagios/libexec directory
Run plugin with the –help flag to see options.

9. Object Definition - Service
Run plugin locally until desired results are obtained
Define command
Define service from command
Add host or hostgroups to be monitored
Define contacts
Define contact group
Define timeperiod

10. Object Definition - Service
Run command sudo /opt/nagios/bin/nagios -v /opt/nagios/etc/nagios.cfg to verify configuration files.
If everything is fine. Add the newly defined object to /opt/nagios/etc/nrpe.cfg file on the client.
Run sudo /etc/init.d/nagios reload. You should see the new object appear in the Pending catagory on the nagios screen.

11. Object Definition - Service
After command runs, check the status within Nagios
I would recommend triggering an event with the new command to test your contacts.

12. Summary Nagios consists of two objects: host and services
Directory structure for the nagios process is: /var/opt/nagios/ while global configuration files can be found under /opt/nagios/etc/.
Object definitions can be found under /opt/nagios/etc/objects
Plugin commands can be found under /opt/nagios/libexec
Abide by basic courtesies while creating objects.
Define, create and test new objects.