UDP in Railgun

[rainest]

Kong 2.2 introduces support for UDP routes.

From a KIC implementation standpoint, TCPIngress has fields similar to what UDP routes will require, i.e. a hostname (handled via TLS SNI) and a port.

The user interface is an open question. Service APIs propose HTTPRoute and TCPRoute resoruces. In our current model, we could introduce a new UDPIngress CRD or augment TCPIngress to support protocols other than TCP, despite the name.

Upstream TLS is an open question. On the Kong end, there are tls, tcp, and udp services, and all are implemented via NGINX streams: Kong/kong@967043e

[mflendrich]

TBD: whether the scope of this issue is only plain UDP (without DTLS) or UDP with DTLS support (DTLS offloading, SNI, etc.).

TBD: whether kubernetes (kube-proxy, networking) works nicely with UDP (including ICMP Port Unreachable, etc.)

[mflendrich]

We need to figure out whether to implement this on top of service-apis or existing KIC APIs. Hence removal of "help wanted".

[mflendrich]

Blocked by #1010 which will give us an answer whether to implement this on top of service-apis or not.

Edit: yes

[mflendrich]

Blocked by #1043 - we need to understand whether this should go to KIC 2.0 or 1.x or both

[shaneutt]

I took a first pass at UDPIngress this in this branch and wanted to share for posterity (but we still do need to complete #1043 before we can move forward).

[shaneutt]

We're going to follow up on my previous branch work and spike a v1alpha1.UDPIngress in railgun.

[shaneutt]

Merged in v1alpha1 and continued work on the UDPIngress API is covered by follow-up issues in the UDPIngress milestone.