Ingress2gateway: The Easy Way to Migrate from Kubernetes Ingress to Gateway API

The Ingress2gateway tool is designed to simplify the transition from Kubernetes Ingress resources to the more powerful and expressive Gateway API. It provides a robust, automated conversion process, ensuring a smooth migration while minimizing disruption.

Key Features and Capabilities:

✅ Automatic Conversion

• Intelligently parses existing Ingress resources and generates equivalent Gateway API configurations, including Gateway, HTTPRoute, and BackendPolicy resources.
• Handles complex Ingress rules, annotations, and configurations, translating them into the corresponding Gateway API specifications.

✅ Preserves Routing Rules:

• Accurately maps URL paths, hostnames, and backend services from Ingress rules to HTTPRoute rules.
• Ensures traffic routing behaviour remains consistent after the migration, preventing unexpected service disruptions.
• It supports various routing features, such as path matching (prefix, exact, regex), hostname matching and header-based routing.

✅ Supports Various Ingress Controllers

• The tool currently supports the apisix, cilium, ingress-nginx, istio, gce, kong and openapi providers and the community is actively working to include additional providers.

✅ Facilitates Gradual Migration:

• Enables incremental adoption of Gateway API by allowing selective conversion of Ingress resources.
• Supports dry-run modes for previewing conversion results before applying changes to the cluster.
• Allows for side-by-side testing of Ingress and Gateway API resources.

To test the tool, you need a Kubernetes cluster with the Gateway API installed. Several projects support the Gateway API, and some cloud providers also offer a fully managed implementation.

In the following example, I am using Google Kubernetes Engine and the default ingress-gce ingress controller in GKE.

Deploying sample workload and ingress resource

• Deploy the sample httpbin workload.

---
apiVersion: v1
kind: Service
metadata:
  name: httpbin
  labels:
    app: httpbin
spec:
  ports:
  - name: http
    port: 8000
    targetPort: 80
  selector:
    app: httpbin
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: httpbin
spec:
  replicas: 1
  selector:
    matchLabels:
      app: httpbin
  template:
    metadata:
      labels:
        app: httpbin
    spec:
      containers:
      - image: docker.io/kennethreitz/httpbin
        imagePullPolicy: IfNotPresent
        name: httpbin
        ports:
        - containerPort: 80

Sample kubernetes deployment and service

• Create an Ingress resource for the httpbin deployment.

---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: httpbin-ingress
  namespace: default
spec:
  rules:
  - host: httpbin.example.com
    http:
      paths:
      - backend:
          service:
            name: httpbin
            port:
              number: 8000
        path: /
        pathType: Prefix

Sample ingress resource

Install and run ingress2gateway

• Follow the installation documentation to install ingress2gateway or download the binary at the releases page.
• Run ingress2gateway for your specific provider. This reads the ingress resources and/or provider-specific CRDs from a Kubernetes cluster or a file and outputs the equivalent Gateway API resources in YAML/JSON format to stdout.

The output will look like this:

sample ingress2gateway generated gatewayapi resources

Note: Ingress2gateway is not intended to copy annotations from Ingress to Gateway API. Instead, the tool converts the annotations to Gateway CRD; widely used provider-specific annotations and/or CRDs may still not be supported. Please refer to supported providers for the current supported providers and their documentation.

Sample gateway api resources

• Verify the generated manifest to ensure it contains all required configurations before implementing them in your production environment. Conduct an end-to-end test before removing the existing ingress resources.