Enterprise Overviews with Nagios/Icinga Nagvis Visualization

This article describes how to install and configure NagVis, a highly customizable add-on visualization package.  Nagios and Icinga include  a basic Map feature that depicts the enterprise, but it is not very customizable.

Icinga-Web and the NagVis Default Automap

NagVis is an add-on for Nagios and Icinga that provides highly-customizable views.  It uses the NDO - IDO database as a source of information.  The Maps are then defined through a dedicated user interface.  Nagvis also includes, by default, an Automap; it is a slightly improved view compared to the Nagios Icinga Map views, but also does not include many customizable features.

The video below depicts the Icinga Web pages to view Hosts, Host Groups, Services and Service Groups and the NagVis Automap feature. 

Creating and Configuring a NagVis Map

NagVis provides much, much more than the default Automap feature.  The Automap only provides Host objects arranged according to Parent relationships as defined in the configuration files.  Custom Maps provide a wide range of Object types (Services, Host and Service Groups, etc.), Backgrounds, and Shapes (images that depict user-defined objects).

An Enterprise Overview Map only needs to provide the highest-level information.  For the systems monitored by this model, that will be:

• A Background Image depicting the geographical area covered
• Shapes to depict WAN Router locations
• Host Icons to depict the WAN Routers
• Host Group icons to depict Data Center servers
• Service Icons to depict WAN Router Interfaces
• Service Group Lines to depict WAN Links
• Service Group Icons to depict the enterprise-wide health of groups of monitored services.

The video below demonstrates how these items are added. 

Nagios / Icinga / NagVis Model

Once the Enterprise Overview is finalized, it depicts all monitored objects as up and running. The whole point of a model is to simulate behavior under real-world conditions.  To do so, a series of WAN link failures on the Philadelphia Router will be simulated.  The failures will be:

1. The router interface on the Philadelphia Router connecting to the Harrisburg Router will be administratively shut down
2. The router interface on the Philadelphia Router connecting to the Pittsburgh Router will be disconnected
3. The router interface on the Philadelphia Router connecting to the Coudersport Router will be disconnected

There is a Nagios server located in the Philadelphia Data Center that will maintain connectivity with the Data Center Hosts.  There is an Icinga server located in the Pittsburgh Data Center that will maintain connectivity with all hosts outside Philadelphia.  The WAN Routers are running OSPF and alternate routes will become active as WAN links fail.

Testing the Model's NagVis Reporting

The expected behavior is:

1. Both monitoring servers will recognize the administratively down interface and report the Interface Service Icon and WAN Link Service Group Line as WARNING Yellow
2. Both monitoring servers will recognize the disconnected interface between Philadelphia and Pittsburgh as report  the Interface Service Icon and WAN Link Service Group Line as DOWN Red
3. When all WAN interfaces on the Philadelphia Router are down, the Pittsburgh Monitoring Server will report the Router as DOWN Red and the child Philadelphia Data Center Host Group Icon (representing four servers) as UNREACHABLE Purple and the Philadelphia Monitoring Server NagVis web service will error because it is unreachable.
4. The Philadelphia Monitoring Server will recognize all Data Center Hosts and Services as available, the Philadelphia Router as available, but with CRITICAL Red interfaces and the remainder of the network as Unreachable.

Upon restoring the WAN Link interfaces, it takes three to four minutes for the two monitoring servers to update the host checks and report all objects as available.

The video below demonstrates that the expected behavior is, indeed, what happens.