support endpoint picker based on host override policy #6456
Description
Description:
Support Endpoint Picker Based on the Host Override Policy: https://www.envoyproxy.io/docs/envoy/latest/api-v3/extensions/load_balancing_policies/override_host/v3/override_host.proto
Host Override Policy selects the endpoint from the header or metadata, and lookup in the cluster endpoints. If there is no available endpoint selected, it will use the fallback policy to select an endpoint in the cluster endpoints.
Introducing a new loadbalancer type HostOverride in BackendTrafficPolicy to make this happen.
apiVersion: gateway.envoyproxy.io/v1alpha1
kind: BackendTrafficPolicy
metadata:
name: host-override-policy
namespace: default
spec:
targetRefs:
- group: gateway.networking.k8s.io
kind: HTTPRoute
name: host-override-route
loadBalancer:
type: HostOverride
hostOverrideSettings:
overrideHostSources:
- header: target-pod
- metadata:
key: "envoy.lb"
path:
- key: "override-host"
---
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
name: static-resolver-route
namespace: default
spec:
parentRefs:
- name: eg
hostnames:
- "www.example.com"
rules:
-
backendRefs:
- kind: Service
name: inference-pool-svc
port: 3000