$ cat noc-narrow.yml
- name: deploy service-specific config
  hosts: batcave
  user: root
  gather_facts: True

  vars_files: 
   - "/home/fedora/toshio/global.yml"
   - "/home/fedora/toshio/nagios.{{ inventory_hostname_short }}.yml"
  tasks:
    - debug: var=inventory_hostname_short
    - debug: var=bigfiles
    - debug: var=tester
    - name: fill up the tftpboot directory
      synchronize: src="{{ bigfiles }}/tftpboot/" dest=/var/tmp/tftpboot/

$ cat ~/global.yml

---
bigfiles: /srv/web/infra/bigfiles
$ cat ~/batcave01.yml 

---
tester: "is a test"

# ansible-playbook noc-narrow.yml  -vvvv
Using /etc/ansible/ansible.cfg as config file
1 plays in noc-narrow.yml
skipping vars_file '/home/fedora/toshio/nagios.{{ inventory_hostname_short }}.yml' due to an undefined variable
Loaded callback default of type stdout, v2.0
skipping vars_file '/home/fedora/toshio/nagios.{{ inventory_hostname_short }}.yml' due to an undefined variable

PLAY [deploy service-specific config] ******************************************

TASK [setup] *******************************************************************
<batcave01.phx2.fedoraproject.org> ESTABLISH SSH CONNECTION FOR USER: root
<batcave01.phx2.fedoraproject.org> SSH: EXEC ssh -C -vvv -o ControlMaster=auto -o ControlPersist=60s -o Port=22 -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o User=root -o ConnectTimeout=90 -o ControlPath=/root/.ansible/cp/ansible-ssh-%h-%p-%r batcave01.phx2.fedoraproject.org LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8 LC_MESSAGES=en_US.UTF-8 /usr/bin/python
ok: [batcave01.phx2.fedoraproject.org]

TASK [debug var=inventory_hostname_short] **************************************
task path: /home/fedora/toshio/ansible/playbooks/groups/noc-narrow.yml:10
ok: [batcave01.phx2.fedoraproject.org] => {
    "changed": false, 
    "inventory_hostname_short": "batcave01", 
    "invocation": {
        "module_args": {
            "var": "inventory_hostname_short"
        }, 
        "module_name": "debug"
    }
}

TASK [debug var=bigfiles] ******************************************************
task path: /home/fedora/toshio/ansible/playbooks/groups/noc-narrow.yml:11
ok: [batcave01.phx2.fedoraproject.org] => {
    "bigfiles": "/srv/web/infra/bigfiles", 
    "changed": false, 
    "invocation": {
        "module_args": {
            "var": "bigfiles"
        }, 
        "module_name": "debug"
    }
}

TASK [debug var=tester] ********************************************************
task path: /home/fedora/toshio/ansible/playbooks/groups/noc-narrow.yml:12
ok: [batcave01.phx2.fedoraproject.org] => {
    "changed": false, 
    "invocation": {
        "module_args": {
            "var": "tester"
        }, 
        "module_name": "debug"
    }, 
    "tester": "VARIABLE IS NOT DEFINED!"
}

TASK [fill up the tftpboot directory] ******************************************
task path: /home/fedora/toshio/ansible/playbooks/groups/noc-narrow.yml:13
An exception occurred during task execution. The full traceback is:
Traceback (most recent call last):
  File "/home/fedora/toshio/ansible-upstream/lib/ansible/executor/process/worker.py", line 135, in run
    shared_loader_obj,
  File "/home/fedora/toshio/ansible-upstream/lib/ansible/executor/task_executor.py", line 119, in run
    res = self._execute()
  File "/home/fedora/toshio/ansible-upstream/lib/ansible/executor/task_executor.py", line 402, in _execute
    result = self._handler.run(task_vars=variables)
  File "/home/fedora/toshio/ansible-upstream/lib/ansible/plugins/action/synchronize.py", line 171, in run
    self._override_module_replaced_vars(task_vars)
  File "/home/fedora/toshio/ansible-upstream/lib/ansible/plugins/action/synchronize.py", line 96, in _override_module_replaced_vars
    localhost = task_vars['hostvars'][host]
  File "<string>", line 2, in __getitem__
  File "/usr/lib64/python2.7/multiprocessing/managers.py", line 759, in _callmethod
    kind, result = conn.recv()
TypeError: ('__init__() takes at least 2 arguments (1 given)', <class 'ansible.errors.AnsibleFileNotFound'>, ())

fatal: [batcave01.phx2.fedoraproject.org]: FAILED! => {"failed": true, "stdout": ""}

PLAY RECAP *********************************************************************
batcave01.phx2.fedoraproject.org : ok=4    changed=0    unreachable=0    failed=1