salt:/srv/salt/ntp# less init.sls
ntp:
    pkg:
        - installed
        - name: ntp
    service:
        - running
        - watch:
            - pkg: ntp
            - file: /etc/ntp.conf

/etc/ntp.conf:
    file:
        - managed
        - user: root
        - group: root
        - mode: 644
           {% if grains['os'] == 'Centos' %}
           - source: salt://ntp/ubuntu-ntp.conf
           {% elif grains['os'] == 'Ubuntu' %}
           - source: salt://ntp/centos-ntp.conf
           {% endif %}