Service 'maas-proxy' failed to reload: sudo: no tty present and no askpass program specified

2016-04-02 06:50:58 [-] Failed configuring proxy.
        Traceback (most recent call last):
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 434, in errback
            self._startRunCallbacks(fail)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 501, in _startRunCallbacks
            self._runCallbacks()
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 588, in _runCallbacks
            current.result = callback(current.result, *args, **kw)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1184, in gotResult
            _inlineCallbacks(r, g, deferred)
        --- <exception caught here> ---
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1126, in _inlineCallbacks
            result = result.throwExceptionIntoGenerator(g)
          File "/usr/lib/python3/dist-packages/twisted/python/failure.py", line 389, in throwExceptionIntoGenerator
            return g.throw(self.type, self.value, self.tb)
          File "/usr/lib/python3/dist-packages/provisioningserver/utils/service_monitor.py", line 306, in reloadService
            yield self._performServiceAction(service, "reload")
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1128, in _inlineCallbacks
            result = g.send(result)
          File "/usr/lib/python3/dist-packages/provisioningserver/utils/service_monitor.py", line 336, in _performServiceAction
            raise ServiceActionError(error_msg)
        provisioningserver.utils.service_monitor.ServiceActionError: Service 'maas-proxy' failed to reload: sudo: no tty present and no askpass program specified

how to reproduce:

1. stop maas-rackd
2. stop maas-regiond
3. stop postgresql

restart in invert order 3 and 2 and you'll see the issue