Nexus ML2 mechanism driver need to specify multiple interfaces per host

[Britt Houser]

There are some L2 topologies in which traffic from a physical server can come into multiple interfaces on the ToR switch configured by the Nexus plugin. In the case of server directly attached to ToR, this is easily taken care of by by port-channel/bonding. However, if an intermediary device (e.g. Cisco UCS Fabric Interconnect) is placed between the server and the Top of Rack switch, then server traffic has the possibility of coming into multiple interfaces on the same switch. So the user needs to be able to specify multiple interfaces per host.

Currently the plugin stores the information in a dictionary defined like this:
  device_dictionary[dev_id, dev_ip, dev_key] = value[0]

In this setup, specifying a second interface would just overwrite the first. We need to either make the dictionary key include the interface, or make the value of the current dictionary key a list instead of single item.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/113009

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/113009
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=2b325fbd20e1ead8ec713c2fd69fd970dab0b405
Submitter: Jenkins
Branch: master

commit 2b325fbd20e1ead8ec713c2fd69fd970dab0b405
Author: Britt Houser <email address hidden>
Date: Fri Aug 8 15:45:51 2014 -0400

    Change nexus_dict to accept port lists

    When users configured a server to have two logical connections to a
    single switch, the nexus driver would never know about the second
    connection because the nexus_dict stored the interface as a single
    value, which would just get overwritten. This has been fixed by
    allowing the port value to be a comma seperated list. All
    operations on ports have been update to loop over multiple ports
    per switch. New test added for host with dual connections to one
    switch.

    Change-Id: Iefb30452083747b45496600c81f8d0a6f378bd08
    Closes-Bug: 1288393