==> /var/log/maas/maas-django.log <==
ERROR 2015-02-10 12:51:29,248 django.request Internal Server Error: /MAAS/clusters/32ec678e-7c67-42e6-9158-7d79907da06d/interfaces/eth1/edit/
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/django/core/handlers/base.py", line 112, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/usr/lib/python2.7/dist-packages/django/contrib/auth/decorators.py", line 22, in _wrapped_view
    return view_func(request, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/django/views/generic/base.py", line 69, in view
    return self.dispatch(request, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/django/views/generic/base.py", line 87, in dispatch
    return handler(request, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/django/views/generic/edit.py", line 228, in post
    return super(BaseUpdateView, self).post(request, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/django/views/generic/edit.py", line 171, in post
    return self.form_valid(form)
  File "/usr/lib/python2.7/dist-packages/maasserver/views/clusters.py", line 224, in form_valid
    return super(ClusterInterfaceEdit, self).form_valid(form)
  File "/usr/lib/python2.7/dist-packages/django/views/generic/edit.py", line 147, in form_valid
    self.object = form.save()
  File "/usr/lib/python2.7/dist-packages/maasserver/forms.py", line 1497, in save
    interface = super(NodeGroupInterfaceForm, self).save(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/django/forms/models.py", line 446, in save
    construct=False)
  File "/usr/lib/python2.7/dist-packages/django/forms/models.py", line 99, in save_instance
    instance.save()
  File "/usr/lib/python2.7/dist-packages/maasserver/models/cleansave.py", line 38, in save
    return super(CleanSave, self).save(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/maasserver/models/timestampedmodel.py", line 55, in save
    return super(TimestampedModel, self).save(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/django/db/models/base.py", line 545, in save
    force_update=force_update, update_fields=update_fields)
  File "/usr/lib/python2.7/dist-packages/django/db/models/base.py", line 582, in save_base
    update_fields=update_fields, raw=raw, using=using)
  File "/usr/lib/python2.7/dist-packages/django/dispatch/dispatcher.py", line 185, in send
    response = receiver(signal=self, sender=sender, **named)
  File "/usr/lib/python2.7/dist-packages/maasserver/signals.py", line 87, in post_save_callback
    callback(instance, original_values, deleted=False)
  File "/usr/lib/python2.7/dist-packages/maasserver/dhcp_connect.py", line 36, in dhcp_post_change_NodeGroupInterface
    configure_dhcp(instance.nodegroup)
  File "/usr/lib/python2.7/dist-packages/maasserver/dhcp.py", line 157, in configure_dhcp
    configure_dhcpv4(nodegroup, ipv4_interfaces, ntp_server)
  File "/usr/lib/python2.7/dist-packages/maasserver/dhcp.py", line 122, in configure_dhcpv4
    return do_configure_dhcp(4, nodegroup, interfaces, ntp_server)
  File "/usr/lib/python2.7/dist-packages/provisioningserver/utils/twisted.py", line 148, in wrapper
    return func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/maasserver/dhcp.py", line 114, in do_configure_dhcp
    client(command, omapi_key=omapi_key, subnet_configs=subnets).wait(60)
  File "/usr/lib/python2.7/dist-packages/crochet/_eventloop.py", line 219, in wait
    result.raiseException()
  File "<string>", line 2, in raiseException
CannotConfigureDHCP: Could not rewrite DHCPv4 server configuration: None
^C
root@vmslab-maas:/home/cisco#