Hiera 5 is now a fully fledged member of the Puppet ecosystem. We've all been using Hiera for several years already, to provide a so-called separation of concerns between Puppet code and configuration data. Essentially, Hiera lets us separate the how (Puppet modules and manifests) from the what (configuration data). This allows us to keep all site-specific and business-specific data out of our manifests, making our Puppet modules vastly more portable. I can recall some time ago in the Puppet community, when Kelsey Hightower first gave us a presentation about separating manifests from data. Well, Hiera 5 finally comes of age in this version, and now allows us complete mastery over this aspect of our infrastructure design.

Hiera provides a key/value lookup facility for configuration data, allowing external lookups of values, and then exposing...