Chapter 6. Higher Abstraction Modules

Most of the modules we can find on the Puppet Forge have one thing in common: they typically manage a single application (Apache, JBoss, ElasticSearch, MySQL and so on) or a system's feature (networking, users, limits, sysctl and so on).

This is a good thing: a rigorous approach to the single responsibility principle is important in order to have modules that can better interoperate, do just what they are expected to do, and behave like libraries that offer well identified and atomic services to their users.

Still our infrastructures are more complex, they require different applications to be configured so as to work together, where configurations may change according to the number and topology of the other components and some kind of cross-application dependencies have to be followed to in order to fulfill a complete setup.

This is generally managed by Puppet users when they group and organize classes according to their needs. Most of the...