Gateway API

Configure HAProxy using Gateway API resources.

Gateway API is a collection of Kubernetes resources that can be installed as Custom Resource Definitions. Just like Ingress resources, Gateway API resources are used to configure incoming HTTP/s and TCP requests to the in cluster applications. HAProxy Ingress v0.14 partially supports the Gateway API spec, v1alpha1 and v1alpha2 versions.

Installation

The following steps configure the Kubernetes cluster and HAProxy Ingress to read and parse Gateway API resources:

  • Manually install the Gateway API CRDs, see the Gateway API documentation
    • … or simply kubectl kustomize "github.com/kubernetes-sigs/gateway-api/config/crd?ref=v0.4.1" | kubectl apply -f -
  • Start (or restart) the controller

See below the getting started steps.

Conformance

Gateway API v1alpha2 spec is partially implemented in the v0.14 release. The following list describes what is (or is not) supported:

  • Target Services can be annotated with Backend or Path scoped configuration keys, this will continue to be supported.
  • Gateway API resources doesn’t support annotations, this is planned to continue to be unsupported. Extensions to the Gateway API spec will be added in the extension points of the API.
  • Only the GatewayClass, Gateway and HTTPRoute resource definitions were implemented.
  • The controller doesn’t implement partial parsing yet for Gateway API resources, changes should be a bit slow on clusters with thousands of Ingress, Gateway API resources or Services.
  • Gateway’s Listener Port and Protocol wasn’t implemented - Port uses the global bind-port configuration and Protocol is based on the presence or absence of the TLS attribute.
  • Gateway’s Addresses wasn’t implemented - binding addresses use the global bind-ip-addr configuration.
  • Gateway’s Hostname only supports empty/absence of Hostname or a single *, any other string will override the HTTPRoute Hostnames configuration without any merging.
  • HTTPRoute’s Matches doesn’t support Headers.
  • HTTPRoute’s Rules and BackendRefs don’t support Filters.
  • Resources status aren’t updated.

Version v1alpha2 should be fully implemented in v0.15 (Q2’22).

Version v1alpha1 support should be dropped in v0.16.

Ingress

A single HAProxy Ingress deployment can manage Ingress, and both v1alpha1 and v1alpha2 Gateway API resources in the same Kubernetes cluster. If the same hostname and path with the same path type is declared in the Gateway API and Ingress, the Gateway API wins and a warning is logged. Ingress resources will continue to be supported in future controller versions, without side effects, and without the need to install the Gateway API CRDs.

Getting started

Add the following steps to the Getting Started guide in order to expose the echoserver service along with the Gateway API:

Manually install the Gateway API CRDs:

kubectl kustomize\
 "github.com/kubernetes-sigs/gateway-api/config/crd?ref=v0.4.1" |\
 kubectl apply -f -

Add the following deployment and service if echoserver isn’t running yet:

kubectl --namespace default create deployment echoserver --image k8s.gcr.io/echoserver:1.3
kubectl --namespace default expose deployment echoserver --port=8080

A GatewayClass enables Gateways to be read and parsed by HAProxy Ingress. Create a GatewayClass with the following content:

apiVersion: gateway.networking.k8s.io/v1alpha2
kind: GatewayClass
metadata:
  name: haproxy
spec:
  controllerName: haproxy-ingress.github.io/controller

Gateways create listeners and allow to configure hostnames. Create a Gateway with the following content:

Note: port and protocol attributes have some limitations.

apiVersion: gateway.networking.k8s.io/v1alpha2
kind: Gateway
metadata:
  name: echoserver
  namespace: default
spec:
  gatewayClassName: haproxy
  listeners:
  - name: echoserver-gw
    port: 80
    protocol: HTTP

HTTPRoutes configure the hostnames and target services. Create a HTTPRoute with the following content, changing echoserver-from-gateway.local to a hostname that resolves to a HAProxy Ingress node:

apiVersion: gateway.networking.k8s.io/v1alpha2
kind: HTTPRoute
metadata:
  labels:
    gateway: echo
  name: echoserver
  namespace: default
spec:
  parentRefs:
  - name: echoserver
  hostnames:
  - echoserver-from-gateway.local
  rules:
  - backendRefs:
    - name: echoserver
      port: 8080

Send a request to our just configured route:

curl http://echoserver-from-gateway.local
wget -qO- http://echoserver-from-gateway.local