Comment 1 for bug 1677372

In most use cases it should be ok when we interpret '2' as novaclient.API_MAX_VERSION, because novaclient api microversion match with nova service microversion.

But if we use high version client(Pike) to talk with low version service(Mitaka), it might not work, when novaclient.API_MAX_VERSION is out of the range that nova service supported, and nova service return HTTP406 to refuse the request. So I think we should do api version discovery and take min(client.microversion, service.microversion) to init novaclient.

I prefer to wait for osc 4.0 to land the change, we don't know exactly which commands will break[1]. I have an idea, we should to add non-voting jenkins job to run functional tests with --os-compute-api-version 2.latest, help us to find the gap.

[1]: https://github.com/openstack/python-openstackclient/blob/master/openstackclient/compute/v2/console.py#L134-L138