Puppet separates the implementation of a type into the type definition and any one of many providers for that type. For instance, the package type in Puppet has multiple providers depending on the platform in use (apt, yum, rpm, and others). Early on in Puppet development there were only a few core types defined. Since then, the core types have expanded to the point where anything that I feel should be a type is already defined by core Puppet. The modules presented in Chapter 5, Custom Facts and Modules, each created their own types using this mechanism. The LVM module created a type for defining logical volumes; the concat module created types for defining file fragments. The firewall module created a type for defining firewall rules. Each of these types represents something on the system with the following properties:

When creating a new type, you have to make sure your new type has these properties. The resource defined by the...