Flapjack is a scalable and distributed monitoring system. It natively talks the Nagios plugin format, and can easily be scaled from 1 server to 1000. Flapjack aims to be simple to set up, configure, and maintain, and easily scales from a single host to multiple.

We’ve created a website monitor, in plain English, which genuinely checks the behaviour of a website, and which returns data in the form of a standard Nagios plugin. Suddenly the barrier to doing truly intelligent website monitoring has been reduced, very significantly.

This is a detailed howto article, but you can skip the parts that you don’t need easily, and it will get you up and running with an enviable Nagios Drupal Monitoring station.

Twitter recently switched from an Apache/Mongrel web infrastructure to one based on Unicorn, a high-performance load balancing application server, and Stormcloud, a Unicorn monitoring and management system. Ben Sandofsky and John Adams from Twitter Engineering explain the benefits.

Monitoring “is it down?” is reactionary. It is better than no monitoring at all, but all it tells you is that there is already a problem. Monitoring is better when it predicts the future and prevents problems.

Non-functional requirements are essentially the often unspoken desires of a product owner or user about how a piece of software works, rather than what it does. We don’t really mean how the software itself behaves, as this can still be captured in behaviour-driven design and acceptance tests; rather we mean aspects of its behaviour over the lifecycle of the application.

When monitoring a Web site, you need to look at it both from a ‘micro’ perspective (i.e. are the individual devices and servers in your infrastructure running smoothly?) and from a ‘macro’ perspective (i.e. do your customers have a pleasant experience when accessing and using your site?; can they use your site’s functionality to conduct their business online?).