Chapter 1. Puppet Development in Isolation
Welcome dear reader. You have arrived at the starting point of the journey to learn Puppet. Whether you have a background in software development, IT infrastructure, or somewhere in between or there about, I believe you have heard people talking about Puppet, and how Puppet can help you automate the configuration management and software deployment processes. I've been using Puppet on a daily basis for the past 4 years, and I feel that it has improved my quality of life at work a lot. I have a background in system administration, and I build software stacks from a set of packages, configuration files, and other types of resources. Prior to Puppet, I used to use various self-written scripts to automate the deployment processes in order to make the process repeatable, but I'm doing much less of that since I discovered Puppet. The problem with scripts, as I see it, is that they are hard to transfer across and to hand over, as scripts are often complex and difficult to read by people who are unfamiliar with the language in which the scripts are written.
Puppet can help you overcome this issue in a two-fold solution:
- Puppet manages resources, such as files, users, and services out of the box. Instead of writing custom Shell scripts to manage resources, we write the Puppet script, which we call the manifest.
- Puppet has its own language called Puppet DSL that is easy to understand by the developers as well as the people involved in the infrastructure.
The moment I start feeling bored with the project I'm working on, because I'm not learning new skills any more, I start to wrap things up, finalize the documentation, and tidy up all the loose ends. The handover process for the project used to involve several days of training followed by a period of several weeks of questions about how the scripts work, and how to change the logic in them. The questions often were as simple as "How do you do this thing in Bash?".
Now the logic has been moved away from the custom scripts to Puppet manifests that are written in Puppet DSL. When I get a question such as "How do I do this in Puppet?", I can reply by saying "Here is a book about Puppet called Learning Puppet. By the end of this chapter, you'll already know how to manage your systems with Puppet". There are dozens of books written on Puppet. This one aims to be a little bit different from those by taking a slightly more practical approach to Puppet development. We will perform the following tasks here:
- Download the Puppet Learning VM
- Take a snapshot of the Learning VM to enable an easy rollback to the original system state
- Start the Learning VM
- Experiment with the Puppet command-line commands:
puppet describe,puppet resource, andpuppet apply