all:
  hosts:
    loadbalancer.example.com:
  children:
    centos:
      children:
        apps:
          hosts:
            app01.example.com:
            app02.example.com:
        databases:
          hosts:
            dbms01.example.com:
            dbms02.example.com:
    ubuntu:
      children:
        frontends:
          hosts:
            frt01.example.com:
            frt02.example.com:
