The hiera-eyaml gem
The last module we're going to look at in this chapter is not a module at all. It's actually a gem that installs an extension for Hiera.
As you recall from earlier, Hiera is a hierarchical data store which allows us to separate our data from our code. For instance, it lets us move the NTP servers we're using out of the manifests.
It supports a wide variety of methods to create a hierarchy, which allows us to supplement or override configuration data needed by various modules.
In fact, several of the modules we've looked at earlier in this chapter have great Hiera bindings. Modules with strong Hiera bindings are constructed in a manner that allows the configuration of the main class to be passed in as parameters. Puppet can query ...