Nagios
Nagios®* is a key component of GroundWork's feature-complete and capability-rich IT monitoring solution. While a satisfactory monitoring solution can often be implemented with Nagios alone, a wide range of open source tools, from a myriad of sources, are available to dramatically improve performance, usability, reporting, scalability, etc. GroundWork has chosen the best of these tools to unify in GroundWork Monitor Community Edition and GroundWork Monitor Professional.
Why is Nagios so popular?
Nagios is a tried and true open source monitoring tool providing these core monitoring functions.
- Monitoring Data Generation: it communicates with each machine or node to check on its health
- Monitoring Scheduling: it lets you set when (how often) you want to check that something's working
- Presentation: a web-based GUI lets you quickly check on the status of nodes with intuitive green-yellow-red indicators
- Event Handling: you can set up what to do when something reports as not working
Ethan Galstad of Nagios
Key to Nagios' runaway popularity is its plugin architecture that allows anyone to write a compatibility script for any device or service, greatly simplifying the process of integrating it into a monitoring setup. At this point, pretty much any piece of hardware and (reasonably) popular application has a Nagios-compatible plugin available for it. Nagios is so widely used that any new hardware or application has a community contributed plugin available almost immediately.
How does Nagios work?
By default, Nagios performs its service checks by polling each device via a network connection and waiting for a response (known as "active checks".) Nagios supports a wide variety of methods for gathering the status and performance metrics on each monitorined host with an active check. For example, Nagios can log in as a user via ssh and run its plugins on the local machine, poll SNMP counters, or even just access open ports. Nagios can also accept its check results as asynchronous "passive" checks, integrate with other monitoring systems, and use many more monitoring methods.
What can you monitor?
Pretty much anything that can return a value on the command line. Most people start with a simple "host alive" or "ping" check confirming that a device is up and running. From there, you can check hardware health (e.g. how full a disk is), network integrity (e.g. is a link working), application status (e.g. how many transactions a database is handling), and anything else to excruciating levels of detail: it mostly depends on what you need to monitor and how much detail you need about it. Typically, you set threshold values for the services you're monitoring, and if a service exceeds a threshold value, that triggers an event. How you handle the event is up to you: you can ignore it, send a notification, launch a script to attempt to restart the service, even wait for it to happen multiple times before acting.
So Why All the Nagios Add-ons?
Nagios' popularity has spawned a broad ecosystem providing enhancements, extensions and customization to Nagios' core functionality.
For example: Nagios configuration files are ordinary text files, making them easy to view and edit with any text editor. However, one small typo or incorrectly set threshold can cause your monitoring to cease functioning. As such, several independent efforts have emerged to support well-ordered structuring of Nagios config files, including point-and-click, GUI-based configuration. (One of those tools, Monarch, is included in GroundWork Monitor.)
GroundWork Monitor takes the best of these Nagios add-ons and unifies them into a fully supported IT monitoring solution.
To get a sense of the breadth and extent of Nagios extensions available, visit the Nagios Exchange at http://www.nagiosexchange.org/.
Choose GroundWork for a Comprehensive, Nagios-based IT Monitoring Solution
GroundWork has determined that IT monitoring adoption was being constrained by the challenges of choosing complementary monitoring tools and unifying them into a comprehensive IT monitoring solution. Nagios is only one of the dozens of best-of-breed tools we've unified into a fully featured IT monitoring package. Email us at [email protected] to find out more.
* Nagios is a registered trademark of Nagios Enterprises
