Deprecating the Ingress Class Annotation
Before the IngressClass resource was added in Kubernetes 1.18, a similar concept of Ingress class was often specified with a kubernetes.io/ingress.class annotation on the Ingress. Although this annotation was never formally defined, it was widely supported by Ingress controllers, and should now be considered formally deprecated.
Although the kubernetes.io/ingress.class annotation is deprecated in Kubernetes, GKE continues to use this annotation.
You cannot use the ingressClassName field to specify a GKE Ingress. You must use the kubernetes.io/ingress.class annotation.
Technical notes
The warning message won't cause any functionality issues. But when we want to remove it, we will need a solution to accommodate both GKE ingress and third-party ingress.
Deprecated annotation
kubernetes.io/ingress.classnotice for ingress charthttps://kubernetes.io/blog/2020/04/02/improvements-to-the-ingress-api-in-kubernetes-1.18/
https://cloud.google.com/kubernetes-engine/docs/concepts/ingress#controller_summary
Technical notes
The warning message won't cause any functionality issues. But when we want to remove it, we will need a solution to accommodate both GKE ingress and third-party ingress.