Modules reusability is a topic that has got more and more attention in recent years, as the more people started use Puppet, more evident the need of having some common and shared code to manage common things.
Reusable modules' main characteristics are as follows:
They can be used by different people without the need to modify their content
They support different OS, and allow easy extension to new ones
They allow users to override the default files provided by the module
They might have an opinionated approach to the managed resources but don't force it
They follow a single responsibility principle and should manage only the application they are made for
Reusability, we must underline, is not an all or nothing feature, we might have different levels of reusability to fulfill the needs of a varying percentage of users.
For example, a module might support Red Hat and Debian derivatives, but not Solaris or AIX: is it reusable? If we use the latter OS, definitely not; if we don...