Drop support for Shoots with Kubernetes version < 1.24 (gardener#8487)

* Remove 1.23 and 1.22 from supported versions

* Remove `ConstraintK8sEqual122`

* Remove constraints for 1.23

* Drop version handling for `HorizontalPodAutoscaler`

* Remove docker as supported CRI

* Adap featuregate validation

* Remove `ConstraintK8sLess124`

* Adapt validation for `TopologyAwareHints` featuregate

* Adapt auditpolicy configmap validation

* Adapt supported admission plugins

* Remove outdated images

* Adapt operatingsystemconfig tests

* Remove old versions in tests and docs

* Refactor shoot care health test

* -----------------Empty separator commit----------------

* Adapt `PodSecurity` migration code

* Adapt more occurrences in docs

* Adapt compare-k8s-controllers.sh

* Adapt more occurrences in code

* Adapt kubescheduler config

* Address PR review feedback from oliver-goetz

* Address PR review feedback from rfranzke

* Add TODO

README.md

@@ -39,15 +39,15 @@ Gardener takes part in the [Certified Kubernetes Conformance Program](https://ww
 
 Continuous conformance test results of the latest stable Gardener release are uploaded regularly to the CNCF test grid:
 
-| Provider/K8s | v1.28 | v1.27 | v1.26 | v1.25 | v1.24 | v1.23 | v1.22 |
-| ------------ | ------------ | ------------ | ------------ | ------------ | ------------ | ------------ | ------------ |
-| **AWS** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20AWS) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20AWS) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20AWS) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20AWS) | [![Gardener v1.23 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.23%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.23%20AWS) | [![Gardener v1.22 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.22%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.22%20AWS) |
-| **Azure** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20Azure) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.26%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20Azure) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20Azure) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20Azure) | [![Gardener v1.23 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.23%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.23%20Azure) | [![Gardener v1.22 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.22%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.22%20Azure) |
-| **GCP** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20GCE) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.26%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20GCE) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20GCE) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20GCE) | [![Gardener v1.23 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.23%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.23%20GCE) | [![Gardener v1.22 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.22%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.22%20GCE) |
-| **OpenStack** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20OpenStack) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.26%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20OpenStack) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20OpenStack) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20OpenStack) | [![Gardener v1.23 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.23%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.23%20OpenStack) | [![Gardener v1.22 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.22%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.22%20OpenStack) |
-| **Alicloud** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20Alibaba%20Cloud) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.26%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20Alibaba%20Cloud) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20Alibaba%20Cloud) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20Alibaba%20Cloud) | [![Gardener v1.23 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.23%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.23%20Alibaba%20Cloud) | [![Gardener v1.22 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.22%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.22%20Alibaba%20Cloud) |
-| **Equinix Metal** | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
-| **vSphere** | N/A | N/A | N/A | N/A | N/A | N/A | N/A |
+| Provider/K8s | v1.28 | v1.27 | v1.26 | v1.25 | v1.24 |
+| ------------ | ------------ | ------------ | ------------ | ------------ | ------------ |
+| **AWS** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20AWS) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20AWS) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20AWS) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20AWS/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20AWS) |
+| **Azure** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20Azure) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.26%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20Azure) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20Azure) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20Azure/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20Azure) |
+| **GCP** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20GCE) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.26%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20GCE) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20GCE) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20GCE/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20GCE) |
+| **OpenStack** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20OpenStack) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.26%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20OpenStack) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20OpenStack) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20OpenStack/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20OpenStack) |
+| **Alicloud** | N/A | [![Gardener v1.27 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.27%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.27%20Alibaba%20Cloud) | [![Gardener v1.26 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.26%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.26%20Alibaba%20Cloud) | [![Gardener v1.25 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.25%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.25%20Alibaba%20Cloud) | [![Gardener v1.24 Conformance Tests](https://testgrid.k8s.io/q/summary/conformance-gardener/Gardener,%20v1.24%20Alibaba%20Cloud/tests_status?style=svg)](https://testgrid.k8s.io/conformance-gardener#Gardener,%20v1.24%20Alibaba%20Cloud) |
+| **Equinix Metal** | N/A | N/A | N/A | N/A | N/A |
+| **vSphere** | N/A | N/A | N/A | N/A | N/A |
 
 Get an overview of the test results at [testgrid](https://testgrid.k8s.io/conformance-gardener).
 

cmd/gardener-controller-manager/app/bootstrappers/bootstrap.go

@@ -71,7 +71,7 @@ func (b *Bootstrapper) Start(parentCtx context.Context) error {
 }
 
 func bootstrapCluster(ctx context.Context, gardenClient client.Client, discoveryClient discovery.DiscoveryInterface, secretsManager secretsmanager.Interface) error {
-	const minKubernetesVersion = "1.22"
+	const minKubernetesVersion = "1.24"
 
 	serverVersion, err := discoveryClient.ServerVersion()
 	if err != nil {

cmd/gardener-controller-manager/app/bootstrappers/bootstrap_test.go

@@ -45,7 +45,7 @@ var _ = Describe("#bootstrapCluster", func() {
 	BeforeEach(func() {
 		fakeClient = fakeclient.NewClientBuilder().WithScheme(kubernetes.GardenScheme).Build()
 		fakeDiscoveryClient = &fakediscovery.FakeDiscovery{Fake: &testing.Fake{}}
-		fakeDiscoveryClient.FakedServerVersion = &version.Info{GitVersion: "1.22.4"}
+		fakeDiscoveryClient.FakedServerVersion = &version.Info{GitVersion: "1.26.4"}
 		sm = fakesecretsmanager.New(fakeClient, namespace)
 	})
 
@@ -55,8 +55,8 @@ var _ = Describe("#bootstrapCluster", func() {
 	})
 
 	It("should return an error because the garden version is too low", func() {
-		fakeDiscoveryClient.FakedServerVersion.GitVersion = "1.16.5"
-		Expect(bootstrapCluster(ctx, fakeClient, fakeDiscoveryClient, sm)).To(MatchError(ContainSubstring("the Kubernetes version of the Garden cluster must be at least 1.22")))
+		fakeDiscoveryClient.FakedServerVersion.GitVersion = "1.22.5"
+		Expect(bootstrapCluster(ctx, fakeClient, fakeDiscoveryClient, sm)).To(MatchError(ContainSubstring("the Kubernetes version of the Garden cluster must be at least 1.24")))
 	})
 
 	It("should generate a global monitoring secret because none exists yet", func() {

docs/README.md

@@ -34,7 +34,6 @@
 * [Default Seccomp Profile](usage/default_seccomp_profile.md)
 * [DNS Autoscaling](usage/dns-autoscaling.md)
 * [DNS Search Path Optimization](usage/dns-search-path-optimization.md)
-* [Dockershim removal](usage/docker-shim-removal.md)
 * [Endpoints and Ports of a Shoot Control-Plane](usage/control-plane-endpoints-and-ports.md)
 * [ExposureClasses](usage/exposureclasses.md)
 * [Hibernate a Cluster](usage/shoot_hibernate.md)

docs/concepts/apiserver.md

@@ -40,7 +40,7 @@ Please see [this](../../example/11-internal-secret.yaml) example manifest.
 ## `Seed`s
 
 `Seed`s are resources that represent seed clusters.
-Gardener does not care about how a seed cluster got created - the only requirement is that it is of at least Kubernetes v1.22 and passes the Kubernetes conformance tests.
+Gardener does not care about how a seed cluster got created - the only requirement is that it is of at least Kubernetes v1.24 and passes the Kubernetes conformance tests.
 The Gardener operator has to either deploy the gardenlet into the cluster they want to use as seed (recommended, then the gardenlet will create the `Seed` object itself after bootstrapping) or provide the kubeconfig to the cluster inside a secret (that is referenced by the `Seed` resource) and create the `Seed` resource themselves.
 
 Please see [this](../../example/45-secret-seed-backup.yaml), [this](../../example/50-seed.yaml), and optionally [this](../../example/40-secret-seed.yaml) example manifests.

docs/development/kubernetes-clients.md

@@ -320,17 +320,17 @@ var (
 )
 
 // update
-shoot.Spec.Kubernetes.Version = "1.22"
+shoot.Spec.Kubernetes.Version = "1.26"
 err := c.Update(ctx, shoot)
 
 // json merge patch
 patch := client.MergeFrom(shoot.DeepCopy())
-shoot.Spec.Kubernetes.Version = "1.22"
+shoot.Spec.Kubernetes.Version = "1.26"
 err = c.Patch(ctx, shoot, patch)
 
 // strategic merge patch
 patch = client.StrategicMergeFrom(shoot.DeepCopy())
-shoot.Spec.Kubernetes.Version = "1.22"
+shoot.Spec.Kubernetes.Version = "1.26"
 err = c.Patch(ctx, shoot, patch)
 ```
 

docs/development/local_setup.md

@@ -50,7 +50,7 @@ For other OS, please check [Go installation documentation](https://golang.org/do
 
 ## Installing kubectl
 
-Install `kubectl`. Please make sure that the version of `kubectl` is at least `v1.22.x`. On macOS run
+Install `kubectl`. Please make sure that the version of `kubectl` is at least `v1.24.x`. On macOS run
 
 ```bash
 brew install kubernetes-cli