Ingress V1 Support

NOTE: Application Gateway for Containers has been released, which introduces numerous performance, resilience, and feature changes. Please consider leveraging Application Gateway for Containers for your next deployment.

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.

yaml 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:

yaml 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:

yaml 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.

yaml 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