Puppet Fundamentals

Puppet manages system configuration as desired state. You describe the outcome you want. Puppet compares that policy with a node and changes the node when its state differs.

The central unit is a resource. A resource can represent a package, file, service, user, scheduled job, or another manageable part of a system. Each resource has a type, a title, attributes, and a desired state.

package { 'nginx':
  ensure => installed,
}

service { 'nginx':
  ensure => running,
  enable => true,
}

This code does not list every shell command required on every platform. The resource provider handles platform-specific work. Your policy stays focused on the result.

The catalog is the contract

A manifest is a Puppet language file with a .pp extension. Manifests can contain resources, classes, functions, and conditional logic for many nodes.

A catalog is different. It is the compiled, node-specific document that lists resources and their dependency relationships for one node. Conditional logic has already been resolved before the agent applies the catalog.