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[Bug 1567844] [NEW] Create Port Error - Conflict with persistent instance

To: yahoo-eng-team@xxxxxxxxxxxxxxxxxxx
From: vk <vikash.kumar@xxxxxxxxxxxxxxxxxx>
Date: Fri, 08 Apr 2016 09:11:32 -0000
Reply-to: Bug 1567844 <1567844@xxxxxxxxxxxxxxxxxx>
Sender: bounces@xxxxxxxxxxxxx
Public bug reported:

Using extended firewall plugin, which uses core_plugin (ML2 plugin) to
create and delete port.

Steps:

1. Delete the router attached  interface.
2. Delete the corresponding router port.
3. Create new port with same IP.

Suspect using same context consecutively to delete and create port,
getting below exception. As, with new context didn't get the error.

Exception:

2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher [req-d240dbe4-6f75-489d-a709-6ff06bb8fa22 admin -] Exception during message handling: New instan
ce <IPAllocation at 0x7fc803f00f90> with identity key (<class 'neutron.db.models_v2.IPAllocation'>, (u'12.0.0.1', u'ebc4f10e-f109-4c80-9f4f-1b0979981318', u'f3c2535c-120e-43ab-a363-db35e49bcb68')) conflicts with persistent instance <IPAllocation at 0x7fc803e10210>
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher Traceback (most recent call last):
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 138, in _
dispatch_and_reply
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     incoming.message))
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 185, in _
dispatch
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     return self._do_dispatch(endpoint, method, ctxt, args)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 127, in _
do_dispatch
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     result = func(ctxt, **new_args)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/opt/stack/neutron-fwaas/neutron_fwaas/services/firewall/nfp_fw/nfp_fw_plugin.py", line 
72, in get_router_interfaces_details
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     context.elevated(), {'port': new_port})
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1115, in create_port
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     result, mech_context = self._create_port_db(context, port)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1089, in _create_port_db
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     port_db = self.create_port_db(context, port)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/opt/stack/neutron/neutron/db/db_base_plugin_v2.py", line 1256, in create_port_db
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     db_port['dns_assignment'] = dns_assignment
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 490, in __exit__
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self.rollback()
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __ex
it__
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     compat.reraise(exc_type, exc_value, exc_tb)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 487, in __exit__
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self.commit()
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 392, in commit
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self._prepare_impl()
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 372, in _prepare_impl
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self.session.flush()
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2019, in flush
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self._flush(objects)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2019, in flush
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self._flush(objects)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2137, in _flush
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     transaction.rollback(_capture_exception=True)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __exit__
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     compat.reraise(exc_type, exc_value, exc_tb)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2101, in _flush
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     flush_context.execute()
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 373, in execute
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     rec.execute(self)
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 532, in execute
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     uow
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 149, in save_obj
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     base_mapper, states, uowtransaction
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 301, in _organize_states_for_save
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     state_str(existing)))
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher FlushError: New instance <IPAllocation at 0x7fc803f00f90> with identity key (<class 'neutron.db.models_v2.IPAllocation'>, (u'12.0.0.1', u'ebc4f10e-f109-4c80-9f4f-1b0979981318', u'f3c2535c-120e-43ab-a363-db35e49bcb68')) conflicts with persistent instance <IPAllocation at 0x7fc803e10210>
2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher
2016-04-08 13:22:28.064 27920 ERROR oslo_messaging._drivers.common [req-d240dbe4-6f75-489d-a709-6ff06bb8fa22 admin -] Returning exception New instance <IPAllocation at 0x7fc803f00f90> with identity key (<class 'neutron.db.models_v2.IPAllocation'>, (u'12.0.0.1', u'ebc4f10e-f109-4c80-9f4f-1b0979981318', u'f3c2535c-120e-43ab-a363-db35e49bcb68')) conflicts with persistent instance <IPAllocation at 0x7fc803e10210> to caller
2016-04-08 13:22:28.064 27920 ERROR oslo_messaging._drivers.common [req-d240dbe4-6f75-489d-a709-6ff06bb8fa22 admin -] ['Traceback (most recent call last):\n', '  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 138, in _dispatch_and_reply\n    incoming.message))\n', '  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 185, in _dispatch\n    return self._do_dispatch(endpoint, method, ctxt, args)\n', '  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 127, in _do_dispatch\n    result = func(ctxt, **new_args)\n', '  File "/opt/stack/neutron-fwaas/neutron_fwaas/services/firewall/nfp_fw/nfp_fw_plugin.py", line 72, in get_router_interfaces_details\n    context.elevated(), {\'port\': new_port})\n', '  File "/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1115, in create_port\n    result, mech_context = self._create_port_db(context, port)\n', '  File "/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1089, in _create_port_db\n    port_db = self.create_port_db(context, port)\n', '  File "/opt/stack/neutron/neutron/db/db_base_plugin_v2.py", line 1256, in create_port_db\n    db_port[\'dns_assignment\'] = dns_assignment\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 490, in __exit__\n    self.rollback()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __exit__\n    compat.reraise(exc_type, exc_value, exc_tb)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 487, in __exit__\n    self.commit()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 392, in commit\n    self._prepare_impl()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 372, in _prepare_impl\n    self.session.flush()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2019, in flush\n    self._flush(objects)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2137, in _flush\n    transaction.rollback(_capture_exception=True)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __exit__\n    compat.reraise(exc_type, exc_value, exc_tb)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2101, in _flush\n    flush_context.execute()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 373, in execute\n    rec.execute(self)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 532, in execute\n    uow\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 149, in save_obj\n    base_mapper, states, uowtransaction\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 301, in _organize_states_for_save\n    state_str(existing)))\n', "FlushError: New instance <IPAllocation at 0x7fc803f00f90> with identity key (<class 'neutron.db.models_v2.IPAllocation'>, (u'12.0.0.1', u'ebc4f10e-f109-4c80-9f4f-1b0979981318', u'f3c2535c-120e-43ab-a363-db35e49bcb68')) conflicts with persistent instance <IPAllocation at 0x7fc803e10210>\n"]

** Affects: neutron
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1567844

Title:
  Create Port Error - Conflict with persistent instance

Status in neutron:
  New

Bug description:
  Using extended firewall plugin, which uses core_plugin (ML2 plugin) to
  create and delete port.

  Steps:

  1. Delete the router attached  interface.
  2. Delete the corresponding router port.
  3. Create new port with same IP.

  Suspect using same context consecutively to delete and create port,
  getting below exception. As, with new context didn't get the error.

  Exception:

  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher [req-d240dbe4-6f75-489d-a709-6ff06bb8fa22 admin -] Exception during message handling: New instan
  ce <IPAllocation at 0x7fc803f00f90> with identity key (<class 'neutron.db.models_v2.IPAllocation'>, (u'12.0.0.1', u'ebc4f10e-f109-4c80-9f4f-1b0979981318', u'f3c2535c-120e-43ab-a363-db35e49bcb68')) conflicts with persistent instance <IPAllocation at 0x7fc803e10210>
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher Traceback (most recent call last):
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 138, in _
  dispatch_and_reply
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     incoming.message))
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 185, in _
  dispatch
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     return self._do_dispatch(endpoint, method, ctxt, args)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 127, in _
  do_dispatch
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     result = func(ctxt, **new_args)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/opt/stack/neutron-fwaas/neutron_fwaas/services/firewall/nfp_fw/nfp_fw_plugin.py", line 
  72, in get_router_interfaces_details
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     context.elevated(), {'port': new_port})
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1115, in create_port
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     result, mech_context = self._create_port_db(context, port)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1089, in _create_port_db
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     port_db = self.create_port_db(context, port)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/opt/stack/neutron/neutron/db/db_base_plugin_v2.py", line 1256, in create_port_db
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     db_port['dns_assignment'] = dns_assignment
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 490, in __exit__
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self.rollback()
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __ex
  it__
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     compat.reraise(exc_type, exc_value, exc_tb)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 487, in __exit__
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self.commit()
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 392, in commit
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self._prepare_impl()
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 372, in _prepare_impl
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self.session.flush()
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2019, in flush
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self._flush(objects)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2019, in flush
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     self._flush(objects)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2137, in _flush
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     transaction.rollback(_capture_exception=True)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __exit__
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     compat.reraise(exc_type, exc_value, exc_tb)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2101, in _flush
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     flush_context.execute()
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 373, in execute
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     rec.execute(self)
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 532, in execute
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     uow
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 149, in save_obj
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     base_mapper, states, uowtransaction
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher   File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 301, in _organize_states_for_save
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher     state_str(existing)))
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher FlushError: New instance <IPAllocation at 0x7fc803f00f90> with identity key (<class 'neutron.db.models_v2.IPAllocation'>, (u'12.0.0.1', u'ebc4f10e-f109-4c80-9f4f-1b0979981318', u'f3c2535c-120e-43ab-a363-db35e49bcb68')) conflicts with persistent instance <IPAllocation at 0x7fc803e10210>
  2016-04-08 13:22:28.061 27920 ERROR oslo_messaging.rpc.dispatcher
  2016-04-08 13:22:28.064 27920 ERROR oslo_messaging._drivers.common [req-d240dbe4-6f75-489d-a709-6ff06bb8fa22 admin -] Returning exception New instance <IPAllocation at 0x7fc803f00f90> with identity key (<class 'neutron.db.models_v2.IPAllocation'>, (u'12.0.0.1', u'ebc4f10e-f109-4c80-9f4f-1b0979981318', u'f3c2535c-120e-43ab-a363-db35e49bcb68')) conflicts with persistent instance <IPAllocation at 0x7fc803e10210> to caller
  2016-04-08 13:22:28.064 27920 ERROR oslo_messaging._drivers.common [req-d240dbe4-6f75-489d-a709-6ff06bb8fa22 admin -] ['Traceback (most recent call last):\n', '  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 138, in _dispatch_and_reply\n    incoming.message))\n', '  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 185, in _dispatch\n    return self._do_dispatch(endpoint, method, ctxt, args)\n', '  File "/usr/local/lib/python2.7/dist-packages/oslo_messaging/rpc/dispatcher.py", line 127, in _do_dispatch\n    result = func(ctxt, **new_args)\n', '  File "/opt/stack/neutron-fwaas/neutron_fwaas/services/firewall/nfp_fw/nfp_fw_plugin.py", line 72, in get_router_interfaces_details\n    context.elevated(), {\'port\': new_port})\n', '  File "/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1115, in create_port\n    result, mech_context = self._create_port_db(context, port)\n', '  File "/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1089, in _create_port_db\n    port_db = self.create_port_db(context, port)\n', '  File "/opt/stack/neutron/neutron/db/db_base_plugin_v2.py", line 1256, in create_port_db\n    db_port[\'dns_assignment\'] = dns_assignment\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 490, in __exit__\n    self.rollback()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __exit__\n    compat.reraise(exc_type, exc_value, exc_tb)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 487, in __exit__\n    self.commit()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 392, in commit\n    self._prepare_impl()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 372, in _prepare_impl\n    self.session.flush()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2019, in flush\n    self._flush(objects)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2137, in _flush\n    transaction.rollback(_capture_exception=True)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/langhelpers.py", line 60, in __exit__\n    compat.reraise(exc_type, exc_value, exc_tb)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py", line 2101, in _flush\n    flush_context.execute()\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 373, in execute\n    rec.execute(self)\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/unitofwork.py", line 532, in execute\n    uow\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 149, in save_obj\n    base_mapper, states, uowtransaction\n', '  File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/persistence.py", line 301, in _organize_states_for_save\n    state_str(existing)))\n', "FlushError: New instance <IPAllocation at 0x7fc803f00f90> with identity key (<class 'neutron.db.models_v2.IPAllocation'>, (u'12.0.0.1', u'ebc4f10e-f109-4c80-9f4f-1b0979981318', u'f3c2535c-120e-43ab-a363-db35e49bcb68')) conflicts with persistent instance <IPAllocation at 0x7fc803e10210>\n"]

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Follow ups

[Bug 1567844] Re: Create Port Error - Conflict with persistent instance
From: Launchpad Bug Tracker, 2016-06-18