Fix get_schema_helper bug in some case

[Dong Jun]

When thread of ovn ovsdb-server is not present, then start or restart neutron-server, manager was set to openvswitch. Neutron-server can no longer connect to ovn ovsdb for occupied port 6642 unless delete manager manually.
Manager "ptcp:6642:10.157.0.159"
    Bridge br-int
        fail_mode: secure

This is not a bug that always exists, it's caused by some neutron recent modification. I will port idlutils.get_schema_helper from ovsdbapp to neutron, and in networking-ovn, will pass try_add_manager=False

I also submitted a bug[1] in neutron a few days ago, now it is merged into this one.

[1] https://bugs.launchpad.net/neutron/+bug/1672590

[Ihar Hrachyshka (ihar-hrachyshka)]

Is that 6642 port something specific used by OVN?

[Han Zhou (zhouhan)]

Jun, what do you mean:
> When thread of ovn ovsdb-server is not present

I am a little bit confused what are the steps to reproduce this problem.

@Ihar, 6642 is the default port of OVN southbound DB. networking-ovn connects to two ovsdb servers: OVN northbound DB (default port 6641) and OVN southbound DB (default port 6642).

[Dong Jun (dongj)]

@Han
You can reproduce it simply by following steps when using TCP connection: 1, Kill ovsdb-server of OVN_Northbound; 2, Restart neutron-server; 3, Start OVN_Northbound ovsdb-server again. Then neutron-server can not establish connection to OVN_Northbound.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/448447
Committed: https://git.openstack.org/cgit/openstack/networking-ovn/commit/?id=826943a91e8ada5ac2014542faf518be4d4abb64
Submitter: Jenkins
Branch: master

commit 826943a91e8ada5ac2014542faf518be4d4abb64
Author: Dong Jun <email address hidden>
Date: Wed Mar 22 16:28:25 2017 +0800

    Fix OvnBaseConnection.get_schema_helper bug in some case

    When thread of ovn ovsdb-server is not present(e.g. kill the process),
    restart neutron-server and then start ovn ovsdb-server, neutron-server
    can no longer connect to ovn ovsdb unless I delete ovs manager manually.
    This bug is not always exists, it's caused by some recent neutron
    modification. Neutron code moved Connection.get_schema_helper() logic
    to idlutils.get_schema_helper()[1], the change affects OvnBaseConnection.
    get_schema_helper(), because enable_connection_uri() is called again.
    Use idlutils._get_schema_helper() instead of idlutils.get_schema_helper()
    to fix this bug.
    [1]https://github.com/openstack/neutron/blob/master/neutron/agent/ovsdb/native/connection.py#L123-L129

    Change-Id: I01a3a65f264bd7e080f9aa2c5e2482dbe07694f4
    Partial-Bug: #1674889
    Signed-off-by: Dong Jun <email address hidden>

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/448861
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=f95d33ec6e58915aeb1fbaa27588334920752eb5
Submitter: Jenkins
Branch: master

commit f95d33ec6e58915aeb1fbaa27588334920752eb5
Author: Dong Jun <email address hidden>
Date: Wed Mar 29 11:58:16 2017 +0800

    Port idlutils.get_schema_helper from ovsdbapp to neutron

    There is a fatal error in networking-ovn in some case, so I port
    idlutils.get_schema_helper from ovsdbapp to neutron and add some unit
    tests. Networking-ovn will pass try_add_manager=False to it.

    Change-Id: I12461c96f7a2845b3155fd587fb1fcc84ecf85f0
    Partial-Bug: #1674889