Preface

Puppet has changed the way we manage our systems. When it was released, other configuration management tools were around, but it was clear that it had something special. It came at the right time with the right approach. The challenges of IT infrastructures were beginning to step up to a new level, and the need to automate common activities such as a quick setup and configuration of systems was becoming a requirement. Puppet presented a sane model, based on abstraction of resources and the definition of the expected state of a system, using a clear and sysadmin-friendly language.

There are various books about Puppet around, and most of them are very good. This one tries to contribute with solid and no frills content (few pictures and few large blocks of copied and pasted text) and some new perspectives and topics. It begins with an intense technical overview of Puppet, Hiera, and PuppetDB so that you can use them to design appropriate Puppet architectures that fit your IT infrastructure.

We will explore where our data can be placed, how to design reusable modules, and how they can be used as building blocks for higher abstraction classes. We will try to give a clearer and wider view of what it means to work with Puppet, and what are the challenges we might face when we introduce it on our systems, from code management to deployment rollouts. We will dive into Puppet's internal details and its extension points, showing the multiple ways we can tweak, extend, and hack with it. We will also give a look to less traditional fields, such as Puppet as a configuration-management tool for network devices or cloud services.

The last chapter is about the future: how Puppet is evolving and what we can expect to do with it in the next years.

I'd dare to say that this is the book I'd have liked to read when I was trying to connect the dots and figure out how to do things in the "right way", struggling to grasp Puppet's inner concepts and reusability patterns.

Years of pain, experience, evolution, and research are poured in these pages and I really hope they can be useful for your personal adventure exploring Puppet.