FREE MONITOR

If you look after more than one computer, eventually you’ll realize you could benefit from some form of automatic monitoring – certainly after someone surprises you with the announcement that a system you are responsible for just crashed. In addition to reducing the response time for a downed system, system monitoring can also help you identify problems in advance – before the situation becomes an emergency. Even if you only have one computer, advanced notification that your disks are getting full or that sshd is down can save considerable time and stress.

If you have a specific service or situation you want to monitor, you could, of course, brew your own custom monitoring script and trigger it with cron. However, you really do not need to go reinventing wheels when several open source applications will handle the job for you. In this article, I look at three of the main contenders – Hobbit, Nagios, and monit. All are open source and freely available. All have good points and limitations. The ideal solution depends on your network, your experience, and your needs.