When we use a backend based on files such as JSON or YAML, which are the most commonly used, we have to recreate on the filesystem the hierarchy defined in our hiera.yaml file; the files that contain Hiera data must be placed in these directories.

Let's see Hiera in action. Provide a sample hierarchy configuration as follows:

:hierarchy:
  - "nodes/%{::fqdn}"
  - "env/%{::env}"
  - common

:yaml:
  :datadir: /etc/puppet/hieradata

We have to create a directory structure as follows:

mkdir -p /etc/puppet/hieradata/nodes
mkdir -p /etc/puppet/hieradata/env

Then, work on the YAML files as shown:

vi /etc/puppet/hieradata/nodes/web01.example42.com.yaml
vi /etc/puppet/hieradata/env/production.yaml
vi /etc/puppet/hieradata/env/test.yaml
vi /etc/puppet/hieradata/common.yaml

The previous files are plain YAML files where we can specify the values for any Hiera-managed variable. These values can be strings, arrays, or hashes.

We can place our default settings...