IngressClass

An Ingress resource can target a specific Ingress controller instance which is useful when running multiple ingress controllers in the same cluster. Targetting an Ingress controller means only a specific controller should handle/implement the ingress resource. This can be done using IngressClassName field.

IngressClassName

The IngressClassName field is available in kubernetes 1.18+ and is the official way to handle this. This field should reference an IngressClass resource that contains the name of the controller that should implement the class. For example, let's consider the following Ingress object:

kind: Ingress
apiVersion: networking.k8s.io/v1
metadata:
  name: test
spec:
  ingressClassName: haproxy
  rules:
    - host: test.k8s.local
      http:
        paths:
          - path: /
            backend:
              serviceName: http-echo
              servicePort: http

If there is a single HAProxy Ingress Controller instance then no need to set --ingress.class, but rather create an IngressClass resource with Spec.Controller set to haproxy.org/ingress-controller

apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
  name: haproxy
spec:
  controller: haproxy.org/ingress-controller

In the other hand if multiple HAProxy Ingress Controllers are deployed then --ingress.class argument can be used to target one of them. This can be done via the following IngressClass (notice Spec.Controller is set to haproxy.org/ingress-controller/prod)

apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
  name: haproxy-prod
spec:
  controller: haproxy.org/ingress-controller/prod

In this case --ingress.class should be set to prod and the ingressClassName field should be haproxy-prod.

Ingress eligibility rules

Inputs

Controller

• --ingress.class: CLI param of the Ingress Controller to select Ingress resources.
• --EmptyIngressClass: CLI param of the Ingress Controller to select Ingress resources with ingress class config.

Ingress resource

• ingressClassName: field in the ingress resource that reference a kubernetes IngressClass.

IngressClass resource

• is-default-class: annotation in ingressClass resource.
• controller: field in the ingressClass resource.

Prerequisites

A matching default IngressClass is true when a valid IngressClass resource is available in the cluster and its is-default-class annotation is enabled.

A matching IngressClass is true when the ingressClassName field of an Ingress resource points to a valid IngressClass.

A valid IngressClass is true when the controller field of the IngressClass is equal to:

• "haproxy.org/ingress-controller" if --ingress.class argument is empty
• "haproxy.org/ingress-controller/<--ingress.class value>" if --ingress.class argument is not empty.

Rules

• If the --ingress.class controller param is not set (empty):
  • Accept Ingress resource with:
    • no ingressClassName field.
    • no IngressClass resource with is-default-class enabled.
  • Accept Ingress resource with:
    • no ingressClassName field.
    • a "matching default IngressClass"
  • Accept Ingress resource with:
    • a "matching IngressClass"
• If the --ingress.class controller param is set (not empty):
  • Accept Ingress resource with:
    • no ingressClassName field.
    • --EmptyIngressClass controller param is enabled.
  • Accept Ingress resource with:
    • no ingressClassName field.
    • a "matching default IngressClass"
  • Accept Ingress resource with:
    • a "matching IngressClass"
• Ignore Ingress resource otherwise.