System Monitoring with Nagios

Nagios is a network monitoring service that is designed to run under Linux or any othe unix-like system with a C compiler.

I have been reading about Nagios for a while and so decided to give it a go. I haven’t put it to full production yet but the trial has already impressed me.

Some of the many features of Nagios include: (extracted from Nagios Documentation)

  • Monitoring of network services (SMTP, POP3, HTTP, NNTP, PING, etc.)
  • Monitoring of host resources (processor load, disk usage, etc.)
  • Simple plugin design that allows users to easily develop their own service checks
  • Parallelized service checks
  • Ability to define network host hierarchy using “parent” hosts, allowing detection of and distinction between hosts that are down and those that are unreachable
  • Contact notifications when service or host problems occur and get resolved (via email, pager, or user-defined method)
  • Ability to define event handlers to be run during service or host events for proactive problem resolution
  • Automatic log file rotation
  • Support for implementing redundant monitoring hosts
  • Optional web interface for viewing current network status, notification and problem history, log file, etc.

Windows hosts will be monitored via a client (NSClient++) installed on the host which talks to the Nagios server. Network devices like managed switches can be monitored to different degrees depending on it’s model and maker. Linksys seems to provide more info to Nagios than Netgear but that is not set in stone, it’s just something I experienced on my tests and haven’t inspected any further.

Nagios has a nice web front end but lacks an Admin interface, all settings have to be done manually on raw text files so if you come from a Windows background you will scream. To compensate that, Nagios seems to be the best documented OpenSource system I’ve come across. All the documentation is available on its website and also on you Nagios web interface.

Installation is very easy and very well documented. I’ve installed it so far under OpenSuse 10.1 and under a Debian based distro, both went really well.

If you are interested in implementing Nagios I would recommend this book:

Building a Monitoring Infrastructure with Nagios
by David Josephesen

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