Istio FAQ: region awareness does not take effect

This article excerpts from istio Learning notes

summary

Use istio Regional awareness , The test found that it didn't work , This article introduces several common reasons .

DestinationRule Not configured outlierDetection

Region awareness is enabled by default , But you need to configure DestinationRule, And specify outlierDetection It will take effect , The main purpose of specifying this configuration is to make istio perception endpoints Whether it is abnormal , At present locality Of endpoints When an exception occurs failover To other places endpoints.

Configuration example :

apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
  name: nginx
spec:
  host: nginx
  trafficPolicy:
    outlierDetection:
      consecutive5xxErrors: 3
      interval: 30s
      baseEjectionTime: 30s

client Not configured service

istio The control plane will issue a separate message for each data plane EDS, Different data plane instances (Envoy) Of locality It may not be the same , Generated EDS It may be different .istio Will get the data plane locality Information , The main way to obtain data is to find the corresponding endpoint Last saved region、zone Etc , If client There is no service, And then there won't be endpoint, The control surface cannot be obtained client Of locality Information , It is impossible to realize regional awareness .

Solution : by client To configure service,selector Choose client Of label. If client It does not provide external services ,service Of ports You can also define a .

Used headless service

If it's a visit headless service, It does not support regional awareness , because istio Would be right headless service Request direct passthrough, No load balancing , The client will directly access dns Resolved pod ip.

Solution : Create another one separately service ( Not headless).