Modernizing Kubernetes Traffic: A Guide to the Gateway API Migration

Image by Alexander Hood from Pixabay

In my previous posts, we explored how to use MetalLB to bring real LoadBalancer IPs to a local Minikube cluster and how to manage them with standard Ingress. But as Kubernetes matures, the community is moving toward a more expressive, role-oriented standard: The Gateway API

If Ingress is the Legacy Path, then the Gateway API is the modern highway. In this guide, I will walk you through a complete migration demonstrating how to swap out your old Ingress controllers for Envoy Gateway. We won’t just move traffic; we’ll leverage Envoy’s power to implement seamless request mirroring and more robust, path-based routing that was previously hidden behind complex annotations.

Pre-requisite is to have metallb configured in the minikube cluster to follow this guide.

Envoy Gateway Architecture

Envoy Gateway

Step 1: Installing the Envoy Gateway Controller

helm install eg oci://docker.io/envoyproxy/gateway-helm --version v1.1.0 -n envoy-gateway-system --create-namespace

This command installs Envoy Gateway into your cluster using Helm, pulling the chart directly from Docker Hub’s OCI registry. It creates a dedicated envoy-gateway-system namespace and deploys the Envoy Gateway controller there, which will watch for GatewayClass and Gateway resources across your cluster.

qvamjak% helm list -n envoy-gateway-system                        
NAME NAMESPACE            REVISION UPDATED                                 STATUS   CHART               APP VERSION
eg   envoy-gateway-system 1        2026-02-18 07:16:54.071637216 +0530 IST deployed gateway-helm-v1.1.0 v1.1.0  

Step 2: Deploy the GatewayClass and Gateway

apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: eg
spec:
  controllerName: gateway.envoyproxy.io/gatewayclass-controller

qvamjak% kubectl create -f gatewayclass.yaml
gatewayclass.gateway.networking.k8s.io/eg created

qvamjak% kubectl get gatewayclass           
NAME   CONTROLLER                                      ACCEPTED   AGE
eg     gateway.envoyproxy.io/gatewayclass-controller   True       28s

qvamjak% cat gateway.yaml    
apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: eg
  namespace: default
spec:
  gatewayClassName: eg
  listeners:
  - name: http
    protocol: HTTP
    port: 80


qvamjak% kubectl create -f gateway.yaml     
gateway.gateway.networking.k8s.io/eg created

Step-3: Install App Hello Green and Blue Whale services

Pls follow the instructions in my earlier Ingress blog

Step-4: Create a HTTP Route

qvamjak% cat whale-route.yaml                                       
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: whale-route
spec:
  parentRefs: [{name: eg}]
  hostnames: ["hello.whale.info"]
  rules:
  - matches: [{path: {type: PathPrefix, value: /green}}]
    filters: [{type: URLRewrite, urlRewrite: {path: {type: ReplacePrefixMatch, replacePrefixMatch: /}}}]
    backendRefs: [{name: hello-green-whale-svc, port: 80}]
  - matches: [{path: {type: PathPrefix, value: /blue}}]
    filters: [{type: URLRewrite, urlRewrite: {path: {type: ReplacePrefixMatch, replacePrefixMatch: /}}}]
    backendRefs: [{name: hello-blue-whale-svc, port: 80}]

The whale-route HTTPRoute attaches itself to the eg Gateway and acts as the traffic cop for anything arriving at hello.whale.info. When a request comes in, Envoy checks the path — if it starts with /green, the /green prefix is silently stripped off and the request is forwarded clean to hello-green-whale-svc .The exact same logic applies for /blue, which routes to hello-blue-whale-svc instead. Rules are evaluated top to bottom, so a request can only match one rule. Any request that doesn't start with /green or /blue — or comes in with a different hostname — simply won't match this route at all and will get a 404 from the gateway.

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I have updated the /etc/hosts with the LB IP Address 192.168.49.100

qvamjak% nslookup hello.whale.info
Server: 127.0.0.53
Address: 127.0.0.53#53
Name: hello.whale.info
Address: 192.168.49.100

Also we can acheive the same by using the modheader extension in the browser to include the following and we can browse directly using http://192.168.49.100/green/ or http://192.168.49.100/blue

• Header name: Host
• Value: hello.whale.info

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