An example of traffic splitting with a gateway is this:
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
name: web-route
namespace: default
spec:
parentRefs:
- name: web-gateway
namespace: default
rules:
- matches:
- path:
type: PathPrefix
value: /
backendRefs:
- name: web-service
port: 80
weight: 80
- name: web-service-v2
port: 80
weight: 20
Reference: https://gateway-api.sigs.k8s.io/api-types/httproute/