Hello,
I installed some months ago a test setup in 4.1.0 with ovn.
Now after updating engine and host to 4.1.1 it seems the services are up but it doesn't work.
If I run a VM with a network device in OVN external provider, it cant' boot and I get this in engine.log:

2017-04-20 15:17:42,285+02 ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (org.ovirt.thread.pool-6-thread-11) [e55e0971-f1e5-4fda-8666-3ce23797027f] EVENT_ID: USER_FAILED_RUN_VM(54), Correlation ID: e55e0971-f1e5-4fda-8666-3ce23797027f, Job ID: 067f6e70-9e70-48bc-be44-d5bd1d9485fd, Call Stack: null, Custom Event ID: -1, Message: Failed to run VM c6 (User: admin@internal-authz).
2017-04-20 15:17:42,317+02 INFO  [org.ovirt.engine.core.bll.RunVmCommand] (org.ovirt.thread.pool-6-thread-11) [e55e0971-f1e5-4fda-8666-3ce23797027f] Lock freed to object 'EngineLock:{exclusiveLocks='[50194eea-f96d-4ebb-bf64-55cef13f4309=<VM, ACTION_TYPE_FAILED_OBJECT_LOCKED>]', sharedLocks='null'}'
2017-04-20 15:17:42,317+02 ERROR [org.ovirt.engine.core.bll.RunVmCommand] (org.ovirt.thread.pool-6-thread-11) [e55e0971-f1e5-4fda-8666-3ce23797027f] Command 'org.ovirt.engine.core.bll.RunVmCommand' failed: EngineException: (Failed with error PROVIDER_FAILURE and code 5050)

Firewall is disabled/stopped at host and engine side (where I installed the central server too) and should not be the problem....

On engine server  I get this into /var/log/ovirt-provider-ovn.log

2017-04-20 16:36:25,355   Request: GET : /v2.0/ports
2017-04-20 16:36:25,355   Connecting to remote ovn database: tcp:127.0.0.1:6641
2017-04-20 16:36:28,422   Failed to connect!
2017-04-20 16:36:28,422   Failed to connect!
Traceback (most recent call last):
  File "/usr/share/ovirt-provider-ovn/neutron.py", line 76, in _handle_request
    content)
  File "/usr/share/ovirt-provider-ovn/neutron.py", line 132, in handle_request
    with OvnNbDb(self.remote) as nb_db:
  File "/usr/share/ovirt-provider-ovn/ovndb/ndb_api.py", line 56, in __init__
    self.connect(tables, remote, self.OVN_NB_OVSSCHEMA_FILE)
  File "/usr/share/ovirt-provider-ovn/ovndb/ovsdb_api.py", line 110, in connect
    OvsDb._connect(self._ovsdb_connection)
  File "/usr/share/ovirt-provider-ovn/ovndb/ovsdb_api.py", line 47, in block
    raise OvsDBConnectionFailed('Failed to connect!')
OvsDBConnectionFailed: Failed to connect!

Initial working versions on engine, where I configured the central server:

Feb 14 17:55:57 Installed: openvswitch-2.6.90-1.el7.centos.x86_64
Feb 14 17:55:57 Installed: openvswitch-ovn-common-2.6.90-1.el7.centos.x86_64
Feb 14 17:55:58 Installed: openvswitch-ovn-central-2.6.90-1.el7.centos.x86_64
Feb 14 17:55:59 Installed: python-openvswitch-2.6.90-1.el7.centos.noarch
Feb 14 17:56:52 Installed: ovirt-provider-ovn-1.0-1.20161219125609.git.el7.centos.noarch

Today as part of the update I got:

Apr 20 11:30:06 Updated: openvswitch-2.7.0-1.el7.centos.x86_64
Apr 20 11:30:06 Updated: openvswitch-ovn-common-2.7.0-1.el7.centos.x86_64
Apr 20 11:30:07 Updated: openvswitch-ovn-central-2.7.0-1.el7.centos.x86_64
Apr 20 11:30:24 Installed: python-openvswitch-2.7.0-1.el7.centos.noarch
Apr 20 11:31:00 Updated: ovirt-provider-ovn-1.0-6.el7.centos.noarch

At the page
https://www.ovirt.org/blog/2016/11/ovirt-provider-ovn/

I see this note about ports:

"
Since OVS 2.7, OVN central must be configured to listen to requests on appropriate ports:

ovn-sbctl set-connection ptcp:6642
ovn-nbctl set-connection ptcp:6641
"

and in my case I indeed passed from 2.6.90 to 2.7.0...

Do I need to run these two commands?
Or any other configuration settings?

Thanks in advance,
Gianluca