Add default backendRefs to the BackendTrafficPolicy

Description:

Adding an HTTP Route for a particular hostname invalidates other routes, which have a match on the context path and headers but use wildcard hostname(s). This makes the creation of a "catch-all" HTTP Route impossible. Such a route can be used when two ingress systems are present in the cluster, for example, for migration to EG.

When a default backendRefs is present in the attached BackendTrafficPolicy, instead of throwing NR, EG can forward the request to it

Relevant Links:

Please, see the discussion in:

• #5500

@zhaohuabing, @arkodg, on your suggestion, I created this request

thanks @sadovnikov, this is similar to the default backend feature in ingress-nginx https://kubernetes.github.io/ingress-nginx/user-guide/default-backend/

This issue has been automatically marked as stale because it has not had activity in the last 30 days.

still valid, still actual

This issue has been automatically marked as stale because it has not had activity in the last 30 days.

👍 to this feature. Currently I see lots of requests in the envoy access log with "response_flags":"NR","route_name":null,"x-envoy-origin-path":null because bots and other automated tools are searching for specific files that don't exist. I can't even see the path that was requested because x-envoy-origin-path is null.

By adding a catch-all route it would remove this noise from the logs.

@lboynton you can define a catch all route (PathPrefix: / which has the lowest match precedence) and return a direct response https://gateway.envoyproxy.io/docs/tasks/traffic/direct-response/#testing-direct-response