Multi-interface Controller support

[Daneyon Hansen]

We must setup 2 interfaces on the controller for the environment to work.

[Daneyon Hansen (danehans)]

Controllers need 2 interfaces for our networking model to function properly. One interface is used for API/GRE endpoints and the other is configured for bridging and is used by Quantum/OVS for VM external connectivity. See this commit for details:

https://github.com/danehans/folsom-manifests/commit/f82ebc46fe993453151c07a268cddbae4019a8a5#commitcomment-2320125

[Mark T. Voelker (mvoelker)]

Daneyon has the aforementioned patch included in a pull request:

https://github.com/CiscoSystems/folsom-manifests/pull/21

However per the review it looks like this pull request needs more work to get it in shape for merging.

[Mark T. Voelker (mvoelker)]

Assigning over to Ian to verify whether this got fixed in the recent repo swap.

[Robert Starmer (starmer)]

Current model still (and in the near future) will require multiple interfaces. A single interface model (for those customers that can / want to use this) is being investigated.

This is only important if nova is expected to provide/manage metadata/dhcp services.

[Robert Starmer (starmer)]

Single interface support can be addressed in a future release. The goal would be to allow the external interface (API) and public network to be the same for some use cases (development environments for example).

A fix that's been evaluated, but not tested to scale is to migrate the external network address onto the external bridge interface, and using the same address for both public and external networks. This still requires a route for metadata, but that route then can reside on the control node.

I recommend reducing this to medium or high for the next release.

[Mark T. Voelker (mvoelker)]

Reducing sev for now per Robert's note.