Open Stack

lzy.dev at gmail.asked: 

> Is there a way to allow nova provision a vm with two NICs in the same network?

Supporting two NICs on the same subnet requires something called "source based routing"
to be properly implemented.

While the linux iproute2 package does support this option, it must be used very precisely
to actually have the traffic using both ports properly.

The same results can be achieved by just  using two overlay subnets, with far less risk of
possible misconfigurations. In the context of cluster managed networking creating additional
overlay subnets is a very simple solution that is not dependent on a specific linux package.

I am not aware of any real benefit to having two IP addresses being on the same subnet
that would be relevant to an OpenStack deployment. It can be valuable when you want two
network interfaces to a Public IPv4 network, but that doesn't strike me as a likely configuration.