Progressive Traffic Shift¶
Scenario: Progressive traffic shift
Progressive traffic shift is a type of canary rollout strategy. It enables you to incrementally shift traffic towards the winning version over multiple iterations of an experiment as shown below.
Tutorials with progressive traffic shift¶
Iter8 uses the
weightObjRef field in the experiment resource to get the current traffic split between versions and/or modify the traffic split. Ensure that this field is specified correctly for each version. The following example demonstrates how to specify
weightObjRef in experiments.
The A/B testing quick start tutorial uses an Istio virtual service for traffic shifting. Hence, the experiment manifest specifies the
weightObjRef field for each version by referencing this Istio virtual service and the traffic fields within the Istio virtual service corresponding to the versions.
versionInfo: baseline: name: flowers-v1 weightObjRef: apiVersion: networking.istio.io/v1alpha3 kind: VirtualService name: routing-rule namespace: default fieldPath: .spec.http.route.weight candidates: - name: flowers-v2 weightObjRef: apiVersion: networking.istio.io/v1alpha3 kind: VirtualService name: routing-rule namespace: default fieldPath: .spec.http.route.weight
You can specify the maximum traffic percentage that is allowed for a candidate version during the experiment. You can also specify the maximum increase in traffic percentage that is allowed for a candidate version during a single iteration of the experiment. You can specify these two controls in the
strategy section of an experiment as follows.
strategy: weights: # additional traffic controls to be used during an experiment # candidate weight will not exceed 75 in any iteration maxCandidateWeight: 75 # candidate weight will not increase by more than 20 in a single iteration maxCandidateWeightIncrement: 20