adapt to k8s v1.20.5, introduce contexts & adapt IT suite to v1.20.5

.ci/integration-tests

@@ -148,7 +148,7 @@ function run_controller() {
         --machine-safety-apiserver-statuscheck-timeout=30s \
         --machine-safety-apiserver-statuscheck-period=1m \
         --machine-safety-orphan-vms-period=30m \
-        --machine-safety-overshooting-period=100ms \
+        --machine-safety-overshooting-period=300ms \
         --leader-elect-lease-duration=1m \
         --leader-elect-renew-deadline=30s \
         --leader-elect-retry-period=15s \

cmd/machine-controller-manager/app/controllermanager.go

@@ -43,7 +43,7 @@ import (
 	"github.com/gardener/machine-controller-manager/cmd/machine-controller-manager/app/options"
 	"github.com/gardener/machine-controller-manager/pkg/handlers"
 	"github.com/gardener/machine-controller-manager/pkg/util/configz"
-	"github.com/prometheus/client_golang/prometheus"
+	prometheus "github.com/prometheus/client_golang/prometheus/promhttp"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
@@ -57,11 +57,13 @@ import (
 	"k8s.io/client-go/tools/leaderelection"
 	"k8s.io/client-go/tools/leaderelection/resourcelock"
 	"k8s.io/client-go/tools/record"
-	"k8s.io/klog"
+	"k8s.io/klog/v2"
 )
 
 const (
 	controllerManagerAgentName = "machine-controller-manager"
+	targetkubeconfigTimeout    = 1 * time.Minute
+	controlkubeconfigTimeout   = 1 * time.Minute
 )
 
 var (
@@ -108,6 +110,8 @@ func Run(s *options.MCMServer) error {
 	controlkubeconfig.QPS = s.KubeAPIQPS
 	targetkubeconfig.Burst = int(s.KubeAPIBurst)
 	controlkubeconfig.Burst = int(s.KubeAPIBurst)
+	targetkubeconfig.Timeout = targetkubeconfigTimeout
+	controlkubeconfig.Timeout = controlkubeconfigTimeout
 
 	kubeClientControl, err := kubernetes.NewForConfig(
 		rest.AddUserAgent(controlkubeconfig, "machine-controller-manager"),
@@ -311,7 +315,7 @@ func getAvailableResources(clientBuilder corecontroller.ClientBuilder) (map[sche
 		}
 
 		healthStatus := 0
-		resp := client.Discovery().RESTClient().Get().AbsPath("/healthz").Do().StatusCode(&healthStatus)
+		resp := client.Discovery().RESTClient().Get().AbsPath("/healthz").Do(context.TODO()).StatusCode(&healthStatus)
 		if healthStatus != http.StatusOK {
 			klog.Errorf("Server isn't healthy yet.  Waiting a little while.")
 			return false, nil