Book Image

Puppet 4 Essentials, Second Edition - Second Edition

By : Felix Frank, Martin Alfke
Book Image

Puppet 4 Essentials, Second Edition - Second Edition

By: Felix Frank, Martin Alfke

Overview of this book

Puppet is a configuration management tool that allows you to automate all your IT configurations, giving you control over what you do to each Puppet Agent in a network, and when and how you do it. In this age of digital delivery and ubiquitous Internet presence, it's becoming increasingly important to implement scalable and portable solutions, not only in terms of software, but also the systems that run it. The free Ruby-based tool Puppet has established itself as the most successful solution to manage any IT infrastructure. Ranging from local development environments through complex data center setups to scalable cloud implementations, Puppet allows you to handle them all with a unified approach. Puppet 4 Essentials, Second Edition gets you started rapidly and intuitively as you’ll put Puppet’s tools to work right away. It will also highlight the changes associated with performance improvements as well as the new language features in Puppet 4. We’ll start with a quick introduction to Puppet to get you managing your IT systems quickly. You will then learn about the Puppet Agent that comes with an all-in-one (AIO) package and can run on multiple systems. Next, we’ll show you the Puppet Server for high-performance communication and passenger packages. As you progress through the book, the innovative structure and approach of Puppet will be explained with powerful use cases. The difficulties that are inherent to a complex and powerful tool will no longer be a problem for you as you discover Puppet's fascinating intricacies. By the end of the book, you will not only know how to use Puppet, but also its companion tools Facter and Hiera, and will be able to leverage the flexibility and expressive power implemented by their tool chain.
Table of Contents (15 chapters)
Puppet 4 Essentials Second Edition
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface
Index

Debugging Hiera lookups


As you can see from the preceding example, the data that contributes to the complete configuration of any module can be rather dispersed throughout the set of your data sources. It can be challenging to determine where the respective values are retrieved from for any given agent node. It can be frustrating to trace data sources to find out why a change at some level will not take effect for some of your agents.

To help make the process more transparent, Hiera comes with a command-line tool called hiera. Invoking it is simple:

root@puppetmaster # hiera -c /etc/puppetlabs/code/hiera.yaml demo::atoms

It retrieves a given key using the specified configuration from hiera.yaml. Make sure that you use the same Hiera configuration as Puppet.

Of course, this can only work sensibly if Hiera selects the same data sources as the compiler, which uses fact values to form a concrete hierarchy. These required facts can be given right on the command line as the final parameters:

root...