External Puppet fact listing running services on a SystemD machine. Depends on python-dbus.

systemd_running_services.py

#!/usr/bin/env python
# This is to be used as an external Puppet fact that can tell you what are the
# currently running services (not all units!) on a SystemD machine.

from dbus import SystemBus, Interface
import re

manager = Interface(
  SystemBus().get_object('org.freedesktop.systemd1', '/org/freedesktop/systemd1'),
  'org.freedesktop.systemd1.Manager')

print '%s: %s' % ('running_services',
      [ str(re.search(r'^([^\.]+)\.service$', unit[0]).group(1))
           for unit in manager.ListUnits()
               if unit[4] == 'running' and re.search(r'.service$', unit[0]) ])