Traffic splitting

Documentation

Traffic splitting

Set up weight-based routing between multiple apps.

Before you begin

Follow the Get started guide to install kgateway.
Follow the Sample app guide to create an API gateway proxy with an HTTP listener and deploy the httpbin sample app.

Get the external address of the gateway and save it in an environment variable.

export INGRESS_GW_ADDRESS=$(kubectl get svc -n kgateway-system http -o jsonpath="{.status.loadBalancer.ingress[0]['hostname','ip']}")
echo $INGRESS_GW_ADDRESS

kubectl port-forward deployment/http -n kgateway-system 8080:8080

Deploy the Helloworld sample app

To demonstrate weighted routing for multiple apps, deploy 3 versions of the Helloworld sample app.

Create the helloworld namespace.
```
kubectl create namespace helloworld
```

Deploy the Hellworld sample apps.

kubectl -n helloworld apply -f https://raw.githubusercontent.com/solo-io/gloo-edge-use-cases/main/docs/sample-apps/helloworld.yaml

Example output:

service/helloworld-v1 created
service/helloworld-v2 created
service/helloworld-v3 created
deployment.apps/helloworld-v1 created
deployment.apps/helloworld-v2 created
deployment.apps/helloworld-v3 created

Verify that the Helloworld pods are up and running.

kubectl -n default get pods -n helloworld

Example output:

NAME                             READY   STATUS    RESTARTS   AGE
helloworld-v1-5c457458f-rfkc7    3/3     Running   0          30s
helloworld-v2-6594c54f6b-8dvjp   3/3     Running   0          29s
helloworld-v3-8576f76d87-czdll   3/3     Running   0          29s

Set up weighted routing

Create an HTTPRoute resource for the traffic.split.example domain that routes 10% of the traffic to helloworld-v1, 10% to helloworld-v2, and 80% to helloworld-v3.

kubectl apply -f- <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: traffic-split
  namespace: helloworld
spec:
  parentRefs:
  - name: http
    namespace: kgateway-system
  hostnames:
  - traffic.split.example
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /
    backendRefs:
    - name: helloworld-v1
      port: 5000
      weight: 10
    - name: helloworld-v2
      port: 5000
      weight: 10
    - name: helloworld-v3
      port: 5000
      weight: 80
EOF

Setting	Description
`spec.parentRefs.name`	The name and namespace of the gateway resource that serves the route. In this example, you use the gateway that you created when you set up the Sample app.
`spec.hostnames`	The hostname for which you want to apply traffic splitting.
`spec.rules.matches.path`	The path prefix to match on. In this example, `/` is used.
`spec.rules.backendRefs`	A list of services you want to forward traffic to. Use the `weight` option to define the amount of traffic that you want to forward to each service.

Verify that the HTTPRoute is applied successfully.

kubectl get httproute/traffic-split -n helloworld -o yaml

Send a few requests to the /hello path. Verify that you see responses from all 3 Helloworld apps, and that most responses are returned from helloworld-v3.

for i in {1..20}; do curl -i http://$INGRESS_GW_ADDRESS:8080/hello \
-H "host: traffic.split.example:8080"; done

for i in {1..20}; do curl -i localhost:8080/hello \
-H "host: traffic.split.example"; done

Example output:

HTTP/1.1 200 OK
server: envoy
date: Wed, 12 Mar 2025 20:59:35 GMT
content-type: text/html; charset=utf-8
content-length: 60
x-envoy-upstream-service-time: 110

Hello version: v3, instance: helloworld-v3-55bfdf76cf-nv545

Cleanup

You can remove the resources that you created in this guide.

Remove the HTTP route resource.

kubectl delete httproute traffic-split -n helloworld

Remove the Helloworld apps.

kubectl delete -n helloworld -f https://raw.githubusercontent.com/solo-io/gloo-edge-use-cases/main/docs/sample-apps/helloworld.yaml

Buffering Resiliency