client.yaml

# /etc/puppet/config/client.yaml
---
client: example.com
environment: vagrant

hiera.yaml

# /etc/puppet/hiera.yaml -- global hiera configuration
---
:backends: - yaml

:hierarchy:
  # global client setting, this file is ignored in git
  # sets the client=someone variable, and possibly environment=something
  - client
  - clients/%{client}
  - clients/%{client}/environments/%{environment}
  - global/roles
  - global

:yaml:
  :datadir: /etc/puppet/config/hiera

hiera_classifier.pp

node default {
    # discover host role and include its classes
    $roles = hiera_hash('roles')
    $hosts = hiera_hash('hosts')
    include $roles['base']
    include $roles[ $hosts[$fqdn]['role'] ]
}

roles.yaml

# /etc/puppet/config/hiera/global/roles.yaml
---
# classes for each role
# syntax:
#
# role_name:
#   - class_name_1
#   - class_name_2
#   - ...
#

roles:

  puppetserver:
    # empty

  graphite:
    - graphite
    - collectd
    - collectd::server

vagrant.yaml

# /etc/puppet/config/clients/example.com/environments/vagrant.yaml
---
roles:
  custom_role_name:
    - custom_class1
    - custom_class2

hosts:
    puppet.vagrant:
        role: puppetserver
    graphite.vagrant:
        role: graphite
    custom.vagrant:
        role: custom_role_name