#### No /etc/puppet/hiera.yaml #####

---
:backends:
  - yaml
:yaml:
  :datadir: /etc/puppet/hieradata
:hierarchy:
  - "%{::clientcert}"
  - "%{::custom_location}"
  - common


#### No /etc/puppet/hieradata/common.yaml #####
---
packages_list:
  - 'postgresql94-contrib'
  - 'pcre-devel'

#### No manifest

class foo {
$packages_list      = hiera('packages_list')
   package { $packages_list:
    ensure  => latest,
  }
}

### Para testar

hiera -c /etc/puppet/hiera.yaml packages_list