Nagios is a great success story of OpenSource software. A monitoring system build with a core set of features, a fast and responsive web interface and a simple API to create custom plugins in whatever language prefered is blowing away the commercial competition. Already established in small and medium IT organisations, it is also making its inroads to enterprise companies through the IT 'backdoor'. Engineers who need to get the job done fast and reliable could not wait for enterprise IT's slow response to cater their quickly changing and increasing needs for monitoring. This did not go unnoticed, and with commercial support available, even large companies move to Nagios as their main monitoring solution.
I noticed Nagios first in 2000, when it was still called NetSaint. We needed operational monitoring for our production firewalls, proxies and load balancers. There, NetSaint fullfilled its job nicely. In the old days, It was quite some work to install the software. After collecting all the necessary source code while making sure not to miss a dependency, almost every component required compilation from hand. This was the typical way of installing before Nagios became mainstream, before it was included into Linux distributions. In the past, commercial UNIX systems had been around more, I was running NetSaint v0.0.6 on a highly available SUN server under Solaris 8, which was also doubling as our central log collection system. Since then, Nagios became the standard tool that was always being deployed for reliable monitoring, and with an ever increasing scope.
Finally in 2008 I deployed Nagios into the enterprise, monitoring up to 1.500 systems with over 5.000 service checks across three Asia datacenters. In addition to performing the operational monitoring of 300 servers, 700 network devices and 500 print centers, Nagios provided the data for independend service provider SLA-monitoring, and the added the graphing of short and longterm trends became the base for capacity and performance planning. Deployment, test and QA teams are very keen on using Nagios data to evaluate application performance in UAT and burn-in tests. For service Outsourcing, the new IT normality, Nagios provides automated alert escalation to our respective service providers. Its modular, extendable design enabled the rapid development of monitoring plugins to address new devices and applications fast, and the active community is a great resource to draw upon.
This site provides documentation, plugins and how-tos to contribute back to the community.
For professional consulting, e.g. on the technologies used on this site, please contact me under support[at]frank4dd[dot]com. I genuinely enjoy working with monitoring solutions such as Nagios.