Learning Puppet 4

Preface

Twenty years ago, it was common for a single server to provide services for hundreds of users. A system administrator was often responsible for as few as 10 servers. Most people used only one computer.

In 2015, it is common for a normal, everyday person to own and utilize more than five highly advanced and capable computers. Think about the devices you use on a daily basis: every one of them—the phone on your desk, the cell phone on your hip, the tablet you read from, your laptop, and even the car you drive—is thousands of times more powerful and capable than the large, room-sized servers used a few generations ago.

We live today in the midst of an information revolution. Systems capable of powerful computation that once required server rooms to contain are now able to be held in your hands. Explosive growth in the adoption and capabilities of modern technology has created a world full of computers. More and more devices every day contain powerful small computers that participate in the Internet of Things.

When I started my career, it was difficult to convince managers that every worker needed his or her own computer. Today, the workers are outnumbered by computers almost 20:1, and in certain industries by as much as 100:1. Advanced computing capability combined with cheap memory have revolutionized what businesses can accomplish with data. Even small teams of people utilize and depend upon thousands of computers. Every one of these devices needs to be managed. It’s simply not possible to do it all by hand.

For this, we use Puppet.

Who This Book Is For

This book is primarily aimed at system administrators and operations or DevOps engineers. If you are responsible for development or production nodes, this book will provide you with immediately useful tools to make your job easier than ever before. If you run a high-uptime production environment, you’re going to learn how Puppet can enforce standards throughout the implementation. Soon you’ll wonder how you ever got along without it.

No matter what you call yourself, if you feel that you spend too much time managing computers, then this book is for you. You’d like to get it done faster so you can focus on something else. You’d like to do it more consistently, so that you don’t have to chase down one-off problems in your reports. Or you’ve got some new demands that you’re looking for a way to solve. If any of these statements fit, Puppet will be one of the best tools in your toolbox.

What to Expect from Me

This book will not be a heavy tome filled with reference material irrelevant to the day-to-day system administrator—exactly the opposite. Throughout this book we will never stray from one simple goal: using Puppet to manage real-life administration concerns.

This book will never tell you to run a script and not tell you what it does, or why. I hate trying to determine what an installation script did, and I won’t do this to you. In this book you will build up the entire installation by hand. Every step you take will be useful to you in a production deployment. You’ll know where every configuration file lives. You’ll learn every essential configuration parameter and what it means.

By the time you have finished this book, you’ll know how Puppet works inside and out. You will have the tools and knowledge to deploy Puppet seamlessly throughout your environment.

What You Will Need

You may use any modern Linux, Mac, or Windows system and successfully follow the hands-on tutorials in this book.

While there are some web dashboards for Puppet, the process of configuring and running Puppet will be performed through the command line. We will help you install all necessary software.

A beginner to system administration can follow every tutorial in this book. Any experience with scripts, coding, or configuration management will enhance what you can get out of this book, but is not necessary. It is entirely possible to deploy Puppet to manage complex environments without writing a single line of code.

Part II documents how to build custom modules for Puppet. You will create modules using the Puppet configuration language that will be taught in this book. When you’ve become an expert in building Puppet modules, you may want to add new extensions to the Puppet configuration language. Some extensions are currently only supported in the Ruby language:

Faces

Add-on subcommands for puppet

Providers

Implementation methods for resource types

Syntax checkers

A tool for validating input

Types

New resources not built into Puppet

Reference materials such as Michael Fitzgerald’s Learning Ruby can be helpful when creating extensions for a custom Puppet module.

What You’ll Find in This Book

The Introduction provides an overview of what Puppet does, how it works, and why you want to use it.

Part I will get you up and running with a working Puppet installation. You will learn how to write declarative Puppet policies to produce consistency in your systems. This part will also cover the changes to the language in Puppet 4.

Part II will introduce you to Puppet modules, the building blocks used for Puppet policies. You will learn how to find and evaluate Puppet modules. You’ll learn how to distinguish Puppet Supported and Puppet Approved modules. You’ll learn tips for managing configuration data in Hiera. Finally, you’ll learn how to build, test, and publish your own Puppet modules.

Part III will help you install the new Puppet Server and the deprecated but stable Puppet master. You’ll learn how to centralize the certificate authority, or use a third-party provider. You will configure an external node classifier (ENC). You’ll find advice and gain experience on how to scale Puppet servers for high availability and performance.

Part IV will review dashboards and orchestration tools that supplement and complement Puppet. The web dashboards provide a way to view the node status and history of changes made by Puppet. The orchestration tools enable you to interact instantly with Puppet nodes for massively parallel orchestration events.

Every step of the way you’ll perform hands-on installation and configuration of every component. There are no magic scripts, no do-it-all installers. You’ll see how easy it is to deploy Puppet from scratch, and experience firsthand the power of the tools it provides. You’ll finish this book with everything you need to build out a production service.

Throughout this book you’ll find commentary and practical advice that is based on years of experience deploying, scaling, and tuning Puppet environments. You will find advice about managing small shops, large commercial enterprises, and globally distributed teams. You’ll also learn several ways to scale Puppet to thousands of nodes.

How to Use This Book

This book provides explicit instructions for configuring and using Puppet from the command line without the use of external tools beyond your favorite text editor.

The book will help you create Puppet manifests and Puppet modules that utilize every feature of Puppet. You will create configuration policies to handle your specific needs from the examples in this book.

Everything you learn in this book can be done entirely from your laptop or workstation without any impact on production environments. However, it will teach you everything necessary to deploy Puppet in real environments, and will include numerous tips and recommendations for production use.

IPv6 Ready

Every example with IP addresses will include both IPv4 and IPv6 statements. If you’re only using one of these protocols, you can ignore the other. Puppet will happily use any combination of them. Specific advice for managing Puppet in dual-stack IPv6 environments can be found in multiple parts of the book.

SSL is now TLS

You are likely familiar with the term SSL when referring to transport layer security and encryption. You’re also likely aware that SSL v3 was renamed TLS 1.0 when it became an IETF standard. At this time, all versions of SSL and up to TLS 1.1 are subject to known exploits. Rather than constantly refer to both terms (SSL/TLS) throughout this book, I will refer to it only by the new name (TLS). This is technically more accurate, as Puppet 4 requires TLS 1.2 and will not accept SSL connections.

Conventions Used in This Book

The following typographical conventions are used in this book:

Italic

Indicates new terms, URLs, email addresses, filenames, and file extensions.

Constant width

Used for program listings, as well as within paragraphs to refer to program elements such as variable or function names, databases, data types, environment variables, statements, and keywords.

Constant width bold

Shows commands or other text that should be typed literally by the user.

Constant width italic

Shows text that should be replaced with user-supplied values or by values determined by context.

Tip

This element signifies a tip or suggestion.

Note

This element signifies a general note.

Warning

This element indicates a warning or caution.

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Content Updates

February 9, 2018

• Documented the new Hiera v5 configuration file format in Chapter 29.

• Documented how to create a simple custom Hiera backend in Chapter 11.

• Removed references to deprecated environment_data_provider and environment::data functions.

• Improved spacing and indentation problems in code examples.

• Clarified how schedules and other dependencies affect resource application.

• Added note about inspect’s removal in Puppet 5 (“Running Audit Inspections” in Chapter 24).

• Improved guidelines for problems with and ways around chained execs.

• Added Semver, SemVerRange, Timespan, and Timestamp values from Puppet 4.8 to “Valid Types” (Chapter 14).

• Added description of Puppet 4.8’s next(), break(), and return() functions in Chapter 5.

• Demonstrated how to redact passwords by marking them Sensitive, in Chapter 5.

• Added instructions for puppet lookup --explain in “Debugging Lookup” (Chapter 14).

• Added the examples/ directory to “Understanding Module Structure” (Chapter 13).

• Fixed all errata reported on the O’Reilly site.

Acknowledgments

I owe a deep debt of gratitude to Nova, Kevin, Andy, Lance, and far too many other friends whom I have neglected while adding “just one more essential thing” (more than a hundred times) to this book. I lack the words to express how thankful I am that you are in my life, and have apparently forgiven me for being a ghost over the last year.

Growing and improving happens only by surrounding yourself with smart people. The following individuals have provided incalculable feedback and insight that has influenced my learning process, and deserve both accolades for their technical efforts and my sincere appreciation for their advice:

• Corey Quinn
• R.I. Pienaar
• Chris Barbour
• William Jiminez
• Rob Nelson

There are far too many Puppet Labs employees to list who have accepted, rejected, and negotiated my suggestions, feedback, and patches to Puppet and related tools. Thank you for your assistance over the years. We all appreciate your efforts far more than we remember to share with you.

I owe a drink and many thanks to many people who provided input and feedback on the book during the writing process, including but definitely not limited to the technical reviewers:

• Eric Sorenson, Puppet Labs
• Anna Kennedy, Redpill-Linpro
• Nick Fagerlund, Puppet Labs

If you find that the examples in this book work well for you, it’s likely due to the helpful feedback provided by numerous readers who posted errata on the book page or comments on the Safari book that helped me address concerns I would have missed. Their insights have been invaluable and deeply appreciated.

And finally, I’d like to thank my O’Reilly editor, Brian Anderson, who gave me excellent guidance on the book and was a pleasure to work with. I’m likewise deeply indebted to my patient and helpful production and copy editors, Kristen and Rachel, without whom my jumbled pile of letters wouldn’t make any sense at all.

All of us who use Puppet today owe significant gratitude to Luke Kanies, who conceived of Puppet and continues to direct its growth in Puppet Labs. His vision and foresight made all of this possible.