Method to ensure that backends see the original client IP address

[youngnick]

Over the past few years, we've seen a number of requests for ensuring that the client IP address is forwarded on to the backend pod. (Without implying PROXY protocol as well, preferably).

For Gateway API implementations that create a Loadbalancer Service, this is often done by setting ExternalTrafficPolicy to local - although this also has the side effect of changing how nodes will respond to traffic bound for the LB Service as well.

Having some method for the user to request that we end up with this behavior is necessary - although in discussions with the maintainers, we've been reluctant to just put something that allows you to set ExternalTrafficPolicy directly, since it's not available if the implementation isn't using an LB Service.

So, this discussion is to talk about ways to represent the request that "client IP address should be visible at the backend Pod" in Gateway API config.

I have some ideas, but would like to hear from everyone else first.