how to convert all kubernetes ingress yamls to use API version networking.k8s.io/v1

Question

Kubernetes Ingress API version networking.k8s.io/v1 has lot of changes in fields wrt extensions/v1beta1 like the following:

* `spec.backend` -> `spec.defaultBackend`
* `serviceName` -> `service.name`
* `servicePort` -> `service.port.name` (for string values)
* `servicePort` -> `service.port.number` (for numeric values)
* `pathType` no longer has a default value in v1; "Exact", "Prefix", or "ImplementationSpecific" must be specified

What is the easiest way to convert all ingress yaml files from extensions/v1beta1 to networking.k8s.io/v1.

Looks like kubectl convert is already deprecated in v1.19.

Kubernetes version:

kubectl version
Client Version: version.Info{Major:"1", Minor:"19", GitVersion:"v1.19.0", GitCommit:"e19964183377d0ec2052d1f1fa930c4d7575bd50", GitTreeState:"clean", BuildDate:"2020-08-26T14:30:33Z", GoVersion:"go1.15", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"19", GitVersion:"v1.19.0", GitCommit:"e19964183377d0ec2052d1f1fa930c4d7575bd50", GitTreeState:"clean", BuildDate:"2020-08-26T14:23:04Z", GoVersion:"go1.15", Compiler:"gc", Platform:"linux/amd64"}

Error while using kubectl convert:

kubectl convert -f ingress_4_10_1.yaml --output-version  networking.k8s.io/v1
kubectl convert is DEPRECATED and will be removed in a future version.
In order to convert, kubectl apply the object to the cluster, then kubectl get at the desired version.
error: networking.Ingress is not suitable for converting to "networking.k8s.io/v1" in scheme "k8s.io/kubernetes/pkg/api/legacyscheme/scheme.go:30"

My ingress yaml:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: frontend
  annotations:
   kubernetes.io/ingress.class: "ing-class1"
spec:
  rules:
  - host:  frontend.com
    http:
      paths:
      - path: /web-frontend/frontend.php
        backend:
          serviceName: frontend
          servicePort: 80

Answer 1

It's not that difficult rewrite it by hand, for example:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: frontend
  annotations:
   kubernetes.io/ingress.class: "ing-class1"
spec:
  rules:
  - host: frontend.com
    http:
      paths:
      - backend:
          service:
            name: frontend
            port:
              number: 80
        path: /web-frontend/frontend.php
        pathType: Exact

Answer 2

Found a nice summary of the required changes in in https://cloud.google.com/kubernetes-engine/docs/deprecations/apis-1-22#ingress-v122

Field	Change
spec.backend	Renamed to spec.defaultBackend.
backend serviceName	Renamed to service.name.
servicePort	Numeric backend servicePort fields are renamed to service.port.number. String backend servicePort fields are renamed to service.port.name.
pathType	Now required for each specified path. The value can be: Prefix, Exact, or ImplementationSpecific. To match the undefined v1beta1 behavior, use ImplementationSpecific.