Trying to understand QuotaSpec & QuotaSpecBinding CRDs

5

@lbudai: In the rate limiting task, we see 5 CRDs being used. My understanding is that out of those the QuotaSpec and QuotaSpecBindings is used by pilot to send mixer client config to the sidecar proxies. In the task, we see the following examples:

apiVersion: config.istio.io/v1alpha2
kind: QuotaSpec
metadata:
  name: request-count
  namespace: istio-system
spec:
  rules:
  - quotas:
    - charge: 1
      quota: requestcount
---
apiVersion: config.istio.io/v1alpha2
kind: QuotaSpecBinding
metadata:
  name: request-count
  namespace: istio-system
spec:
  quotaSpecs:
  - name: request-count
    namespace: istio-system
  services:
  - name: productpage
    namespace: default
    #  - service: '*'  # Uncomment this to bind *all* services to request-count

This means that pods that are part of the productpage service in the default namespace ask for the quota named request-count defined in the istio-system namespace. Further the request-count quota charges 1 unit for each request. You can verify this by looking at the config_dump from the envoy sidecar. That’s my understanding. Hope that helps.