OpenShift Service Mesh tutorial of 4 (4) - traffic management

Pro rata distribution traffic

This section To configure traffic distribution policy Fontend micro services, in order to control and distribute to the destination Backend_v1 Backend_v2 access traffic.

1. In Kiali console enter Services-> backend, click Action, select Create Weighted Routing drop-down menu.
   
2. Weight will backend_v1 in the Create Weighted Routing dialog box is set to 80. Then open Hide Advanced Options, the Add LoadBalance set to ON, and make sure LoadBalancer is ROUND_ROBIN strategy. Finally, click the Create button. The system creates Destination Rule and Virtual Service objects depending on the configuration.
   
3. Above creation DestinationRule and VirtualService in Kiali console can also be done by the following command.

$ oc apply -f istio-files/destination-rule-backend-v1-v2.yml -n my-istio-app
$ oc apply -f istio-files/virtual-service-backend-v1-v2-80-20.yml -n my-istio-app

4. In Kiali enter Istio Config, you can view VirtualService and DestinationRul configuration.
   
   
   
5. Continue with the following script, see the difference when used in the Graph.

$ scripts/run-50.sh

6. Edit DestinationRule, change the weight ratio. Save and then run the previous step, send test request and view the results.

$ oc get DestinationRule -n my-istio-app
NAME      HOST      AGE
backend   backend   20h
$ oc edit DestinationRule backend -n my-istio-app

Traffic Mirroring

The request made at the same time the average traffic distribution between Backend_v1 and Backend_v2, the request will be sent to Backend_v3 micro mirror service. This scenario is typically used for application testing or traffic monitoring.

1. Deployment Backend_v3 micro-services.

$ oc apply -f ocp/backend-v3-deployment.yml -n my-istio-app
$ oc apply -f ocp/backend-v3-service.yml -n my-istio-app

2. VirtualService execute command to create a new configuration backend-virtual-service, delete the original backend of VirtualService.

$ oc apply -f istio-files/virtual-service-backend-v1-v2-mirror-to-v3.yml -n my-istio-app
$ oc delete VirtualService backend -n my-istio-app

Where virtual-service-backend-v1-v2-mirror-to-v3.yml the following content.

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: backend-virtual-service
spec:
  hosts:
   backend
  http:
   route:
    - destination:
        host: backend
        subset: v1
      weight: 80
    - destination:
        host: backend
        subset: v2
      weight: 20
    mirror:
      host: backend-v3

3. Continue with the following script.

$ scripts/run-50.sh

4. Log in to view Backend_v3 another new window you confirm backend_v3 can receive each request through traffic mirroring.

$ oc logs -f <backend_v3 pod> -c backend -n my-istio-app

5. Finally, delete the relevant Istio Policy configuration, leaving only three micro-services.

$ oc delete -f istio-files/virtual-service-backend-v1-v2-mirror-to-v3.yml -n my-istio-app
$ oc delete -f istio-files/destination-rule-backend-v1-v2.yml -n my-istio-app
$ oc delete -f ocp/backend-v3-deployment.yml -n my-istio-app
$ oc delete -f ocp/backend-v3-service.yml -n my-istio-app