Some of the recipes in this book represent best practices as agreed upon by the Puppet community. Others are tips and tricks which will make it easier for you to work with Puppet, or introduce you to features that you may not have been previously aware of. Some recipes are shortcuts that I wouldn't recommend you use as standard operating procedure, but may be useful in emergencies. Finally, there are some experimental recipes that you may like to try, but are only useful or applicable in very large-scale infrastructures or otherwise unusual circumstances.
My hope is that, by reading through and thinking about the recipes presented here, you will gain a deeper and broader understanding of how Puppet works and how you can use it to improve your infrastructure. Only you can decide whether a particular recipe is appropriate for you and your organization, but I hope this collection will inspire you to experiment, find out more, and most of all have fun using Puppet!
Because Linux distributions, such as Ubuntu, Red Hat, and CentOS differ in the specific details of package names, configuration file paths, and many other things, I have decided that for reasons of space and clarity the best approach for this book is to pick one distribution (Ubuntu 12.04 Precise) and stick to that. However, Puppet runs on most popular operating systems, so you should have very little trouble adapting the recipes to your own favored OS and distribution.
At the time of writing, Puppet 3.2 is the latest stable version available, and consequently I have chosen that as the reference version of Puppet used in the book. The syntax of Puppet commands changes often, so be aware that while older versions of Puppet are still perfectly usable, they may not support all of the features and syntax described in this book.