Ingress V1 Support

This document describes AGIC's implementation of specific Ingress resource fields and features. As the Ingress specification has evolved between v1beta1 and v1, any differences between versions are highlighted to ensure clarity for AGIC users.

Note: Ingress/V1 is fully supported with AGIC >= 1.5.1

Kubernetes Versions

For Kubernetes version 1.19+, the API server translates any Ingress v1beta1 resources to Ingress v1 and AGIC watches Ingress v1 resources.

IngressClass and IngressClass Name

AGIC now supports using ingressClassName property along with kubernetes.io/ingress.class: azure/application-gateway to indicate that a specific ingress should processed by AGIC.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: shopping-app
spec:
  ingressClassName: azure-application-gateway
  ...

Ingress Rules

Wildcard Hostnames

AGIC supports wildcard hostnames as documented by the upstream API as well as precise hostnames.

Wildcard hostnames are limited to the whole first DNS label of the hostname, e.g. *.foo.com is valid but *foo.com, foo*.com, foo.*.com are not. * is also not a valid hostname.

PathType property is now mandatory

AGIC now supports PathType in Ingress V1.

Exact path matches will now result in matching requests to the given path exactly.
Prefix patch match type will now result in matching requests with a "segment prefix" rather than a "string prefix" according to the spec (e.g. the prefix /foo/bar will match requests with paths /foo/bar, /foo/bar/, and /foo/bar/baz, but not /foo/barbaz).
ImplementationSpecific patch match type preserves the old path behaviour of AGIC < 1.5.1 and allows to backwards compatibility.

Example Ingress YAML with different pathTypes defined:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: shopping-app
spec:
  rules:
  - http:
      paths:
      - path: /foo             # this would stay /foo since pathType is Exact
        pathType: Exact
      - path: /bar             # this would be converted to /bar* since pathType is Prefix
        pathType: Prefix
      - path: /baz             # this would stay /baz since pathType is ImplementationSpecific
        pathType: ImplementationSpecific
      - path: /buzz*           # this would stay /buzz* since pathType is ImplementationSpecific
        pathType: ImplementationSpecific

Behavioural Change Notice

Starting with AGIC 1.5.1,
- AGIC will now strip * from the path if PathType: Exact
- AGIC will now append * to path if PathType: Prefix
Before AGIC 1.5.1,
- PathType property was ignored and path matching was performed using Application Gateway wildcard path patterns.
- Paths prefixed with * were treated as Prefix match and without were treated as Exact match.
To continue using the old behaviour, use PathType: ImplementationSpecific match type in AGIC 1.5.1+ to ensure backwards compatibility.

Here is a table illustrating the corner cases where the behaviour has changed:

AGIC Version	< 1.5.1	< 1.5.1	>= 1.5.1	>= 1.5.1
PathType	Exact	Prefix	Exact	Prefix
Path	/foo*	/foo	/foo*	/foo
Applied Path	/foo*	/foo	/foo (* is stripped)	/foo* (* is appended)

Example YAML illustrating the corner cases above:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: shopping-app
spec:
  rules:
  - http:
      paths:
      - path: /foo*            # this would be converted to /foo since pathType is Exact
        pathType: Exact
      - path: /bar             # this would be converted to /bar* since pathType is Prefix
        pathType: Prefix
      - path: /baz*             # this would stay /baz* since pathType is Prefix
        pathType: Prefix

Mitigation

In case you are affected by this behaviour change in mapping the paths, You can modify your ingress rules to use PathType: ImplementationSpecific so to retain the old behaviour.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: shopping-app
spec:
  rules:
  - http:
      paths:
      - path: /path*         # this would stay /path* since pathType is ImplementationSpecific
        pathType: ImplementationSpecific