gistfile1.yml

salt-minion:
  pkg:
    - installed
  service: 
    - running
    - require:
      - pkg: salt-minion
    - watch:
      - file: /etc/salt/minion.d/grains.conf

/etc/salt/minion.d/grains.conf:
  file: 
    - managed
    {% if salt['cp.hash_file']('salt://minion/' + grains['id'] + '.conf') %}
    - source: {{'salt://minion/' + grains['id'] + '.conf'}}
    {% else %}
    - source: salt://minion/default.conf
    {% endif %}