How to handle non-trivial canary routing

[jrbushell]

Examples of canary routing that I've seen, such as the one at https://gateway-api.sigs.k8s.io/guides/traffic-splitting/, are all basic examples, typically a user's request handled by one service and no further interactions, like this:

user -> Gateway -> HTTPRoute -> Service (v1/v2) 

This is fine, but it's common to have more service layers hiding behind your frontend, and I might want to do canary routing on those services as well, e.g. by some header passed through from one service to the next.

user -> Gateway -> HTTPRoute -> Service A (v1/v2) -> Service B (v1/v2) [ ... and maybe more services ... ]

What's the right way to handle that? Should I route Service B through the same Gateway, or a separate Gateway, or is Gateway just not the right tool here?

[azemoning]

In such a case, I would use the Gateway API and Service Mesh tools such as Istio or Linkerd, so the Gateway API will handle the north/south traffic (user -> Gateway -> HTTPRoute -> Service (v1/v2)), and the service mesh will handle the east/west traffic (Service A (v1/v2) -> Service B (v1/v2)).

https://gateway-api.sigs.k8s.io/concepts/use-cases/#gateway-and-mesh-use-case
https://gateway-api.sigs.k8s.io/mesh/