Puppet modules are getting better and better: they are more reusable, they better fit just what they are supposed to do, and they offer stable and reliant interfaces to the management of different applications.

They are, therefore, getting nearer to the status where they can be considered as shared libraries that can be used by different users to compose the configurations needed in their environments.

Here is where many people are struggling in order to achieve a sane organization of resources, good patterns to group them, and better approaches to a dynamic, reproducible, structured, and maybe, reusable management of complete stacks of applications.

Using these higher abstraction layer modules, people are experimenting with different practices; some have become common, such as the roles and profiles pattern, but still, few are engineered with the vision to be reusable and eventually allow single components to be composed freely to fit different topologies.

In this chapter, we have focused...