Open Stack

On Mon, Aug 01, 2016 at 08:10:18AM -0400, Jim Rollenhagen wrote:
> Hey all,
> 
> Our nova patch for networking[0] got stuck for a bit, because Nova needs
> to know which network interface is in use for the node, in order to
> properly set up the port.
> 
> The code landed for network_interface follows the following order for
> what is actually used for the node:
> 1) node.network_interface, if that is None:
> 2) CONF.default_network_interface, if that isNone:
> 3) flat, if using neutron DHCP
> 4) noop, if not using neutron DHCP
> 
> The API will return None for node.network_interface in the API (GET
> /v1/nodes/uuid). This won't work for Nova, because Nova can't know what
> CONF.default_network_interface is.
> 
> I propose that if a network_interface is not sent in the node-create
> call, we write whatever the current default is, so that it is always set
> and not using an implicit value that could change.
> 
> For nodes that exist before the upgrade, we do a database migration to
> set network_interface to CONF.default_network_interface (or if that's
> None, set to flat/noop depending on the DHCP provider).
> 
> An alternative is to keep the existing behavior, but have the API return
> whatever interface is actually being used. This keeps the implicit
> behavior (which I don't think is good), and also doesn't provide a way
> to find out from the API if the interface is actually set, or if it's
> using the configurable default.
> 
> I'm going to go ahead and execute on that plan now, do speak up if you
> have major objections to it.

By the way, the patch chain to do this is here:
https://review.openstack.org/#/q/status:open+project:openstack/ironic+branch:master+topic:bug/1608511

// jim