Interface support

[kfox1111]

It would be nice if you could specify which interface to bind to rather then which ip address. This would make it easier to manage within a cluster.

[danderson]

Edited - danderson made confused sounding noises because he wasn't looking at the project name for this bug

[kfox1111]

Oh. sorry. Was looking at the pixiecore code and forgot there were other pieces. a -i to pixiecore as an alternate option to -l. I need to bind it to a particular network, but the ip's vary per host.

[danderson]

Oh, er. Sorry, I'm just massively confused and thought that this was a bug for MetalLB, my other side-project. Oops.

Yeah, an interface selector sounds reasonable. I'm vaguely surprised it's not already there.

[danderson]

I've forgotten how most of pixiecore works, but two ways of doing this:

• cmdline flag only, which gets resolved and translated into Server.Address in pixiecore.go
• Add a Server.Interface string in pixiecore.go, and some logic to allow Address XOR Interface, and resolve appropriately to a listen addr for the socket bind.