Make listener can expose >1 ports

[izturn]

What would you like to be added:
The Gateway Listener only gives us one port to specify, there is no way to set the specific node port for the service type: LoadBalancer instead of generate it by random, I hope there is a method to accomplish it

We had talked about it in the project contour, but maybe here is the right place.

xref: projectcontour/contour#5072

Why this is needed:

[shaneutt]

Hi @izturn, thanks for your request! 👋

I understand that fundamentally what you'd like to be able to do is have a field on Gateway listeners to explicitly declare a port that will then be used as the NodePort in the underlying Service type LoadBalancer that your implementation is creating, correct?

It's important to note that while Service type LoadBalancer is in use "under the hood" in several Gateway API implementations, there is no explicit relationship between Gateway and Service and nor is there any relevant requirements. Some implementations of Gateway API today do not use the Service API. So the Gateway listener may not be the right place to put such a thing, but we can certainly explore the problem you're trying to solve further and look for solutions.

I noticed in your initial issue that the Why this is needed field has been omitted. To find an optimal solution it could be helpful for us to better understand the underlying need. Could you please fill out this section with details about what problem(s) this solves, including example situations?

[costinm]

In Istio implementation - and the pattern can probably be used by any other implementation that does have associated Service objects - the user can create a Service with the same name as the Gateway, and the implementation will just use it ( or create one if it doesn't exist ). If I remember correctly - the selector will be patched or needs to have a specific value.

[robscott]

/priority backlog
/triage accepted