enable_connection_uri fails with constraint violation due to duplicate manager

[Ihar Hrachyshka]

When multiple agents interact with the same local ovsdb (which is a reasonable use case, f.e. when there is both ovs and dhcp agents), then we get the following error in one of agent logs:

2017-03-16 16:06:22.790 14431 ERROR neutron.agent.ovsdb.impl_vsctl [req-1d2c2121-ef13-45a6-81ec-9cfeda8221a7 - - - - -] Unable to execute ['ovs-vsctl', '--timeout=10', '--oneline', '--format=json', '--', '--id=@manager', 'create', 'Manager', 'target="ptcp:6640:127.0.0.1"', '--', 'add', 'Open_vSwitch', '.', 'manager_options', '@manager']. Exception: Exit code: 1; Stdin: ; Stdout: ; Stderr: ovs-vsctl: transaction error: {"details":"Transaction causes multiple rows in \"Manager\" table to have identical values (\"ptcp:6640:127.0.0.1\") for index on column \"target\". First row, with UUID 60a3bbc6-2904-4e1f-8f92-387a315e1142, existed in the database before this transaction and was not modified by the transaction. Second row, with UUID c7bc4f11-5fbc-42e1-b8ec-44324439cace, was inserted by this transaction.","error":"constraint violation"}

Apparently, two agents clash on manager creation. They should atomically append instead.

An example of failure at:

http://logs.openstack.org/98/446598/1/check/gate-neutron-dsvm-fullstack-ubuntu-xenial/2e0f93e/logs/dsvm-fullstack-logs/TestOvsConnectivitySameNetworkOnOvsBridgeControllerStop.test_controller_timeout_does_not_break_connectivity_sigkill_GRE-and-l2pop,openflow-native_ovsdb-cli_/neutron-openvswitch-agent--2017-03-16--16-06-05-730632.txt.gz?#_2017-03-16_16_06_22_790

It's not clear whether it results in any user visible problem.

[Trevor McCasland (twm2016)]

I believe this has already been reported here https://bugs.launchpad.net/neutron/+bug/1681945

[Baojun Jia (nail.jia)]

Hi，Have you solved this bug?