I understand the mixer adapter model through which we can configure what attributes get sent to which adapter under what conditions. Basically all the stuff described here: https://istio.io/docs/concepts/policies-and-telemetry/
But the CRDs QuotaSpec and QuotaSpecBinding used in the rate-limiting task seem completely different from this adapter model. Can someone explain which Istio entity acts upon this CRD? I see that part of what is specified in this CRD flows down to the envoy config as well - how and why?
Is it not possible to do rate limiting using only the adapters? As per the guide “The Envoy sidecar logically calls Mixer before each request to perform precondition checks”, so enforcing rate limits should be possible using only an adapter right?
@mandarjog: would appreciate your help in clarifying this.