Cannot add a device, got a "django.db.utils.IntegrityError: duplicate key value violates unique constraint "maasserver_interface_pkey" DETAIL: Key (id)=(2) already exists." message in the regiond log

[Ricardo Bánffy]

While running MAAS from trunk (r 4363, "make run") I got a

2015-10-08 11:03:16 [-] Error on request (20) device.create: duplicate key value violates unique constraint "maasserver_interface_pkey"
 DETAIL: Key (id)=(2) already exists.

 Traceback (most recent call last):
   File "/usr/lib/python2.7/threading.py", line 783, in __bootstrap
     self.__bootstrap_inner()
   File "/usr/lib/python2.7/threading.py", line 810, in __bootstrap_inner
     self.run()
   File "/usr/lib/python2.7/threading.py", line 763, in run
     self.__target(*self.__args, **self.__kwargs)
   File "/home/ricardo/canonical/maas/src/provisioningserver/utils/twisted.py", line 791, in _worker
     return super(ThreadPool, self)._worker()
 --- <exception caught here> ---
   File "/usr/lib/python2.7/dist-packages/twisted/python/threadpool.py", line 191, in _worker
     result = context.call(ctx, function, *args, **kwargs)
   File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 118, in callWithContext
     return self.currentContext().callWithContext(ctx, func, *args, **kw)
   File "/usr/lib/python2.7/dist-packages/twisted/python/context.py", line 81, in callWithContext
     return func(*args,**kw)
   File "/home/ricardo/canonical/maas/src/maasserver/utils/orm.py", line 480, in call_within_transaction
     return func_outside_txn(*args, **kwargs)
   File "/home/ricardo/canonical/maas/src/maasserver/utils/orm.py", line 307, in retrier
     return func(*args, **kwargs)
   File "/usr/lib/python2.7/dist-packages/django/db/transaction.py", line 339, in inner
     return func(*args, **kwargs)
   File "/home/ricardo/canonical/maas/src/maasserver/websockets/handlers/device.py", line 307, in create
     data = super(DeviceHandler, self).create(params)
   File "/home/ricardo/canonical/maas/src/maasserver/websockets/base.py", line 362, in create
     obj = form.save()
   File "/home/ricardo/canonical/maas/src/maasserver/forms.py", line 1108, in save
     node.add_physical_interface(mac)
   File "/home/ricardo/canonical/maas/src/maasserver/models/node.py", line 913, in add_physical_interface
     node=self, mac_address=mac, name=name)
   File "/usr/lib/python2.7/dist-packages/django/db/models/manager.py", line 157, in create
     return self.get_queryset().create(**kwargs)
   File "/usr/lib/python2.7/dist-packages/django/db/models/query.py", line 319, in create
     obj.save(force_insert=True, using=self.db)
   File "/home/ricardo/canonical/maas/src/maasserver/models/cleansave.py", line 38, in save
     return super(CleanSave, self).save(*args, **kwargs)
   File "/home/ricardo/canonical/maas/src/maasserver/models/timestampedmodel.py", line 70, 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 573, in save_base
     updated = self._save_table(raw, cls, force_insert, force_update, using, update_fields)
   File "/usr/lib/python2.7/dist-packages/django/db/models/base.py", line 654, in _save_table
     result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
   File "/usr/lib/python2.7/dist-packages/django/db/models/base.py", line 687, in _do_insert
     using=using, raw=raw)
   File "/usr/lib/python2.7/dist-packages/django/db/models/manager.py", line 232, in _insert
     return insert_query(self.model, objs, fields, **kwargs)
   File "/usr/lib/python2.7/dist-packages/django/db/models/query.py", line 1511, in insert_query
     return query.get_compiler(using=using).execute_sql(return_id)
   File "/usr/lib/python2.7/dist-packages/django/db/models/sql/compiler.py", line 898, in execute_sql
     cursor.execute(sql, params)
   File "/usr/lib/python2.7/dist-packages/django/db/backends/util.py", line 69, in execute
     return super(CursorDebugWrapper, self).execute(sql, params)
   File "/usr/lib/python2.7/dist-packages/django/db/backends/util.py", line 53, in execute
     return self.cursor.execute(sql, params)
   File "/usr/lib/python2.7/dist-packages/django/db/utils.py", line 99, in __exit__
     six.reraise(dj_exc_type, dj_exc_value, traceback)
   File "/usr/lib/python2.7/dist-packages/django/db/backends/util.py", line 53, in execute
     return self.cursor.execute(sql, params)
 django.db.utils.IntegrityError: duplicate key value violates unique constraint "maasserver_interface_pkey"
 DETAIL: Key (id)=(2) already exists.

trace in the region log

[Blake Rouse (blake-rouse)]

This only happens with sampledata, its an issue on how django reset the id sequence after it runs the fixture.

[Blake Rouse (blake-rouse)]

Just keep performing the command in the dev environment and it will start working.