Istio流量镜像

Istio的流量镜像也叫影子流量，是将生产的流量镜像拷贝到测试集群或者其他版本中去，简单地说也就是引导实时流量到另一个微服务的版本中去。

将流量路由到reviews:v1版本

我们先应用之前的virtual-service-all-v1.yaml，将流量路由到微服务的v1版本

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: productpage
spec:
  hosts:
  - productpage
  http:
    - route:
        - destination:
            host: productpage
            subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: details
spec:
  hosts:
  - details
  http:
    - route:
        - destination:
            host: details
            subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: ratings
spec:
  hosts:
  - ratings
  http:
    - route:
        - destination:
            host: ratings
            subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
  - reviews
  http:
    - route:
        - destination:
            host: reviews
            subset: v1

我们刷新下/productage页面，发现流量确实都路由到reviews:v1版本了,看下reviews:v1日志

reviews:v1日志中确实有访问日志，一会我们将流量镜像到reviews:v2版本，目前reviews:v2是没有访问日志的

将流量镜像到reviews:v2版本

应用virtualservice规则

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
    - reviews
  http:
    - route:
        - destination:
            host: reviews
            subset: v1
      mirror:
        host: reviews
        subset: v2

刷新/productage页面，查看reviews的v1和v2版本的日志

我们发现2个版本的微服务版本日志中都有访问日志的输出，v1访问的流量确实被镜像到了v2版本中去