Remove Ingress API selection code (#4643)

* chore(docs) add #4641 changelog entry

* chore(controllers) remove Ingress API selection

Remove Ingress API selection in favor of simply honoring the CLI disable
flag.

Support for Ingress versions other than networking/v1 was removed in
#3867. The API
selection code was only selecting between networking/v1 and nothing.
Future Kubernetes versions are not expected to abruptly remove the older
API versions if they introduce new Ingress versions, so this selection
code should not be necessary in the future.

CHANGELOG.md

@@ -116,6 +116,12 @@ Adding a new version? You'll need three changes:
   `/status` from Kong Gateway.
   This happens when Gateway is responding with a 50x HTTP status code.
   [#4627](https://github.com/Kong/kubernetes-ingress-controller/issues/4627)
+- Ensure the API server is available at startup and do not disable CRD
+  controllers if Kong CRDs are unavailable. Do not disable the Ingress
+  controller if the Ingress API is unavailable. This avoids incorrectly
+  deleting existing configuration during an API server restart.
+  [#4641](https://github.com/Kong/kubernetes-ingress-controller/issues/4641)
+  [#4643](https://github.com/Kong/kubernetes-ingress-controller/issues/4643)
 
 ## [2.11.1]
 

internal/manager/controllerdef.go

@@ -2,7 +2,6 @@ package manager
 
 import (
 	"context"
-	"fmt"
 	"reflect"
 
 	"k8s.io/apimachinery/pkg/runtime/schema"
@@ -67,15 +66,7 @@ func setupControllers(
 	featureGates map[string]bool,
 	kongAdminAPIEndpointsNotifier configuration.EndpointsNotifier,
 	adminAPIsDiscoverer configuration.AdminAPIsDiscoverer,
-) ([]ControllerDef, error) {
-	restMapper := mgr.GetClient().RESTMapper()
-
-	// Choose the best API version of Ingress to inform which ingress controller to enable.
-	ingressConditions, err := NewIngressControllersConditions(c, restMapper)
-	if err != nil {
-		return nil, fmt.Errorf("ingress version picker failed: %w", err)
-	}
-
+) []ControllerDef {
 	referenceIndexers := ctrlref.NewCacheIndexers()
 
 	controllers := []ControllerDef{
@@ -97,7 +88,7 @@ func setupControllers(
 		// Core API Controllers
 		// ---------------------------------------------------------------------------
 		{
-			Enabled: ingressConditions.IngressClassNetV1Enabled(),
+			Enabled: c.IngressClassNetV1Enabled,
 			Controller: &configuration.NetV1IngressClassReconciler{
 				Client:           mgr.GetClient(),
 				Log:              ctrl.LoggerFrom(ctx).WithName("controllers").WithName("IngressClass").WithName("netv1"),
@@ -107,7 +98,7 @@ func setupControllers(
 			},
 		},
 		{
-			Enabled: ingressConditions.IngressNetV1Enabled(),
+			Enabled: c.IngressNetV1Enabled,
 			Controller: &configuration.NetV1IngressReconciler{
 				Client:                     mgr.GetClient(),
 				Log:                        ctrl.LoggerFrom(ctx).WithName("controllers").WithName("Ingress").WithName("netv1"),
@@ -445,7 +436,7 @@ func setupControllers(
 		},
 	}
 
-	return controllers, nil
+	return controllers
 }
 
 // baseGatewayCRDs returns a slice of base CRDs required for running all the Gateway API controllers.

internal/manager/run.go

@@ -223,7 +223,7 @@ func Run(ctx context.Context, c *Config, diagnostic util.ConfigDumpDiagnostic, d
 	}
 
 	setupLog.Info("Starting Enabled Controllers")
-	controllers, err := setupControllers(
+	controllers := setupControllers(
 		ctx,
 		mgr,
 		dataplaneClient,
@@ -235,9 +235,6 @@ func Run(ctx context.Context, c *Config, diagnostic util.ConfigDumpDiagnostic, d
 		clientsManager,
 		adminAPIsDiscoverer,
 	)
-	if err != nil {
-		return fmt.Errorf("unable to setup controller as expected %w", err)
-	}
 	for _, c := range controllers {
 		if err := c.MaybeSetupWithManager(mgr); err != nil {
 			return fmt.Errorf("unable to create controller %q: %w", c.Name(), err)