README.md

Istio - Weight-based routing

https://istio.io/docs/tasks/traffic-management/traffic-shifting/#apply-weight-based-routing

In Canary Deployments, newer versions of services are incrementally rolled out to users to minimize the risk and impact of any bugs introduced by the newer version.

Route a percentage of traffic to one service or another - send %50 of traffic to reviews:v1 and %50 to reviews:v3 and finally complete the migration by sending %100 of traffic to reviews:v3.

Route all traffic to the reviews:v1 version of each microservice:

kubectl apply -f samples/bookinfo/networking/virtual-service-all-v1.yaml

Transfer 50% of the traffic from reviews:v1 to reviews:v3:

kubectl apply -f samples/bookinfo/networking/virtual-service-reviews-50-v3.yaml
kubectl get virtualservice reviews -o yaml

Output:

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
  ...
spec:
  hosts:
  - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1
      weight: 50
    - destination:
        host: reviews
        subset: v3
      weight: 50

Refresh the /productpage in your browser and you now see red colored star ratings approximately 50% of the time.

Check the flows in Kiali graph, where only reviews:{v1,v2} are used:

Assuming you decide that the reviews:v3 microservice is stable, you can route 100% of the traffic to reviews:v3 by applying this virtual service.

kubectl apply -f samples/bookinfo/networking/virtual-service-reviews-v3.yaml
kubectl get virtualservice reviews -o yaml

Output:

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
...
spec:
  hosts:
  - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v3

When you refresh the /productpage you will always see book reviews with red colored star ratings for each review.

Kiali graph: