What's Puppet

Puppet is an open-source IT automation tool. The Puppet Domain Specific Language (DSL, will discuss in the up-coming section) is a Ruby-based coding language that provides a precise and adaptable way to describe a desired state for each machine in your infrastructure. Once you've described a desired state, Puppet does the work to bring your systems in line and keep them there.

The easy-to-read syntax of Puppet's DSL gives you an operating-system-independent language to specify which packages should be installed, what services you want running, which users accounts you need, how permissions are set, and just about any other detail of a system you might want to manage. If you're the DIY type or have unique needs, you can write the Puppet code to do all these things from scratch. But if you'd rather not re-invent the wheel, a wide variety of pre-made Puppet modules can help you get the setup you're looking for without pounding out the code yourself.

Why not just run a few shell commands or write a script? If you're comfortable with shell scripting and concerned with a few changes on a few machines, this may indeed be simpler. The appeal of Puppet is that it allows you to describe all the details of a configuration in a way that abstracts away from operating system specifics, then manage those configurations on as many machines as you like. It lets you control your whole infrastructure (think hundreds or thousands of nodes) in a way that is simpler to maintain, understand, and audit than a collection of complicated scripts.