A/B testing with Ingress in Kubernetes - Commands & Configuration

Introduction

A/B testing helps you compare two versions of an app by sending some users to one version and others to a different version. Using Kubernetes Ingress, you can control traffic routing to different app versions easily without changing your app code.

When you want to test a new feature on a small group of users before full release

When you want to compare performance between two app versions running in parallel

When you want to gradually shift traffic from an old version to a new version

When you want to route users based on specific rules like cookies or headers

When you want to run experiments to improve user experience without downtime

Config File - ingress-ab-testing.yaml

ingress-ab-testing.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
  annotations:
    nginx.ingress.kubernetes.io/canary: "true"
    nginx.ingress.kubernetes.io/canary-weight: "20"
spec:
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: stable-service
            port:
              number: 80
      - path: /
        pathType: Prefix
        backend:
          service:
            name: canary-service
            port:
              number: 80

This Ingress routes traffic for example.com. The stable-service handles most traffic. The canary-service is marked as a canary with 20% traffic using annotations. This means 20% of users go to the canary version for testing, while 80% use the stable version.

Commands

This command creates or updates the Ingress resource that controls traffic routing for A/B testing between stable and canary services.

Terminal

kubectl apply -f ingress-ab-testing.yaml

Expected Output

ingress.networking.k8s.io/example-ingress created

This command checks that the Ingress resource is created and shows its current status and rules.

Terminal

kubectl get ingress example-ingress

Expected Output

NAME              CLASS    HOSTS         ADDRESS        PORTS   AGE

example-ingress   <none>   example.com   192.168.99.100 80      10s

This command shows detailed information about the Ingress, including annotations and backend services used for routing.

Terminal

kubectl describe ingress example-ingress

Expected Output

Name:             example-ingress

Namespace:        default

Address:          192.168.99.100

Default backend:  <none>

Rules:

  Host        Path  Backends

  ----        ----  --------

  example.com

              /   stable-service:80 (10.0.0.1:80)

              /   canary-service:80 (10.0.0.2:80)

Annotations:

  nginx.ingress.kubernetes.io/canary: true

  nginx.ingress.kubernetes.io/canary-weight: 20

Events:          <none>

This command verifies that the canary version pods are running and ready to receive traffic.

Terminal

kubectl get pods -l app=canary-service

Expected Output

NAME                             READY   STATUS    RESTARTS   AGE

canary-service-5d8f7f7d7b-abc12 1/1     Running   0          5m

Key Concept

If you remember nothing else from this pattern, remember: Kubernetes Ingress can split traffic between stable and canary services using annotations to enable safe A/B testing.

Common Mistakes

Not adding the canary annotations to the Ingress resource

Without annotations, all traffic goes to the stable service, so no A/B testing happens.

Always add 'nginx.ingress.kubernetes.io/canary: "true"' and 'nginx.ingress.kubernetes.io/canary-weight' annotations to enable traffic splitting.

Using the same path for both stable and canary without specifying canary annotations

Ingress will route all traffic to the first matching backend, ignoring the canary service.

Use canary annotations and weights to tell Ingress how to split traffic between services.

Not verifying that canary pods are running before applying Ingress

Traffic sent to canary service will fail if pods are not ready, causing errors for users.

Check canary pods are running and ready with 'kubectl get pods -l app=canary-service' before routing traffic.

Summary

Create an Ingress resource with canary annotations to split traffic between stable and canary services.

Apply the Ingress and verify it is created and configured correctly.

Check that canary pods are running to safely receive test traffic.

Use annotations to control the percentage of traffic sent to the canary version.