Comment 1 for bug 1792031

Restarting, saw this:

2018-09-11 21:02:19 maasserver.dhcp: [info] Successfully configured DHCPv6 on rack controller 'ycqan6'.
2018-09-11 21:02:19 maasserver.rack_controller: [critical] Failed configuring DHCP on rack controller 'id:1'.
        Traceback (most recent call last):
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1442, in gotResult
            _inlineCallbacks(r, g, deferred)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1432, in _inlineCallbacks
            deferred.errback()
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 500, in errback
            self._startRunCallbacks(fail)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 567, in _startRunCallbacks
            self._runCallbacks()
        --- <exception caught here> ---
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 653, in _runCallbacks
            current.result = callback(current.result, *args, **kw)
          File "/usr/lib/python3/dist-packages/maasserver/rack_controller.py", line 256, in <lambda>
            d.addErrback(lambda f: f.trap(NoConnectionsAvailable))
          File "/usr/lib/python3/dist-packages/twisted/python/failure.py", line 359, in trap
            self.raiseException()
          File "/usr/lib/python3/dist-packages/twisted/python/failure.py", line 385, in raiseException
            raise self.value.with_traceback(self.tb)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1386, in _inlineCallbacks
            result = g.send(result)
          File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 835, in configure_dhcp
            raise ipv4_exc
          File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 773, in configure_dhcp
            omapi_key=config.omapi_key)
        provisioningserver.rpc.exceptions.CannotConfigureDHCP: timed out

2018-09-11 21:02:22 maasserver.dhcp: [critical] Error configuring DHCPv4 on rack controller 'ycqan6':
        Traceback (most recent call last):
        Failure: twisted.internet.defer.CancelledError:

2018-09-11 21:02:22 maasserver.dhcp: [info] Successfully configured DHCPv6 on rack controller 'ycqan6'.
2018-09-11 21:02:22 maasserver.rack_controller: [critical] Failed configuring DHCP on rack controller 'id:1'.
        Traceback (most recent call last):
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1442, in gotResult
            _inlineCallbacks(r, g, deferred)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1432, in _inlineCallbacks
            deferred.errback()
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 500, in errback
            self._startRunCallbacks(fail)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 567, in _startRunCallbacks
            self._runCallbacks()
        --- <exception caught here> ---
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 653, in _runCallbacks
            current.result = callback(current.result, *args, **kw)
          File "/usr/lib/python3/dist-packages/maasserver/rack_controller.py", line 256, in <lambda>
            d.addErrback(lambda f: f.trap(NoConnectionsAvailable))
          File "/usr/lib/python3/dist-packages/twisted/python/failure.py", line 359, in trap
            self.raiseException()
          File "/usr/lib/python3/dist-packages/twisted/python/failure.py", line 385, in raiseException
            raise self.value.with_traceback(self.tb)
          File "/usr/lib/python3/dist-packages/twisted/internet/defer.py", line 1386, in _inlineCallbacks
            result = g.send(result)
          File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 835, in configure_dhcp
            raise ipv4_exc
          File "/usr/lib/python3/dist-packages/maasserver/dhcp.py", line 773, in configure_dhcp
            omapi_key=config.omapi_key)