blue.spantree.net.yaml

---
classes:
  - nginx

nginx::mail: false
nginx::manage_repo: false

nginx::nginx_upstreams:
  'nexus-real':
    ensure: present
    members:
      - 'localhost:8080'

nginx::nginx_vhosts:
  'nexus-frontend':
    ensure: present
    proxy: 'http://nexus-real'
    server_name:
      - 'localhost'
      - 'blue.spantree.net'

common.yaml

---
classes:
  - motd
  - ssh

hiera.yaml

---
:backends: 
  - yaml

:hierarchy:
  - common
  - "%{::fqdn}"

:logger: console

:yaml:
  :datadir: '/usr/local/etc/puppet/hieradata'

I am getting this error:

Error: regsubst(): Bad regular expression `\' on node blue.spantree.net
Error: regsubst(): Bad regular expression `\' on node blue.spantree.net