In this chapter, we have reviewed and summarized the basic Puppet principles that are a prerequisite to better understand the contents of the book. We have seen how Puppet is configured and what its main components are: manifests, resources, nodes, and classes, and the power of the Resource Abstraction Layer.

The most useful language elements have been described: variables, references, resources defaults and ordering, conditionals, and comparison operators. We have taken a look at exported and virtual resources and analyzed the structure of a module. We also learned how to work with ERB templates. Finally, we have seen how Puppet's filebucket works and how to recover files modified by Puppet.

We are now ready to face a very important component of the Puppet ecosystem: Hiera, and see how it can be used to separate our data from Puppet code.