Puppet – Hiera lookup functions

By default, puppet only submits a hiera query when it is trying to find a value for a class parameter. OUtside of that, hiera doesn’t get used by puppet. As for your manifests, you will mainly be using data available from facter and puppet built-in variables.

However if there is certain data that you want to use in your manifests, but are stored in yaml files. Then you can instruct puppet to perform a hiera lookup using a number of functions:

There is a fourth a hiera related function, which is called “hiera_include“. Hiera include can assign classes to nodes. Will cover more about that later.

https://docs.puppetlabs.com/hiera/1/puppet.html#hiera-lookup-functions