Lab 8: Traffic Mirroring

Traffic mirroring, also called shadowing, is a powerful concept that provides a risk-free method of testing your releases in the production environment without impacting your end users.

Instead of using traditional pre-production environments which used to be a replica of production, mirroring can provide synthetic traffic to mimic the live environment.

Traffic monitoring works in the following way:

• You deploy a new version of your component (v2)
• The existing version (v1) works loke before but sends an asynchronous copy to the new version
• The new version (v2) processes the incoming traffic but does not respond to the user (fire-and-forget)
• The Dev and Ops teams can monitor the new version in order to identify potential problems before starting the rollout

Let’s start the Lab.

1. Create a Virtual Service that sends all traffic to v1 of the reviews service

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

   ``

   Run the following:

   kubectl apply -f ~/training/istio/samples/bookinfo/networking/virtual-service-all-v1.yaml
    
   > virtualservice.networking.istio.io/reviews configured
   
   

   ``

2. Create a Virtual Service that sends all traffic to v1 and mirrors it to v2 of the reviews service

   apiVersion: networking.istio.io/v1alpha3
   kind: VirtualService
   metadata:
     name: reviews
   spec:
     hosts:
     - reviews
     http:
     - route:
       - destination:
           host: reviews
           subset: v1
       mirror:
         host: nginx
         subset: v2
   mirror_percent: 100
   

   ``

   Run the following:

   kubectl apply -f ~/training/istio/samples/bookinfo/networking/virtual-service-mirror-v1-v2.yaml
    
   > virtualservice.networking.istio.io/reviews configured
   
   

   ``

After a short while you should see traffic starting to flow from reviews (v2) to ratings, because reviews (v2) is receiving the mirrored traffic.