Remove the limitation on exposing port 10250 externally

Author: RyanAoh

pkg/apis/core/validation/validation.go

@@ -58,7 +58,6 @@ import (
 	podshelper "k8s.io/kubernetes/pkg/apis/core/pods"
 	corev1 "k8s.io/kubernetes/pkg/apis/core/v1"
 	"k8s.io/kubernetes/pkg/capabilities"
-	"k8s.io/kubernetes/pkg/cluster/ports"
 	"k8s.io/kubernetes/pkg/features"
 	"k8s.io/kubernetes/pkg/fieldpath"
 )
@@ -5762,16 +5761,6 @@ func ValidateService(service *core.Service) field.ErrorList {
 	}
 	switch service.Spec.Type {
 	case core.ServiceTypeLoadBalancer:
-		for ix := range service.Spec.Ports {
-			port := &service.Spec.Ports[ix]
-			// This is a workaround for broken cloud environments that
-			// over-open firewalls.  Hopefully it can go away when more clouds
-			// understand containers better.
-			if port.Port == ports.KubeletPort {
-				portPath := specPath.Child("ports").Index(ix)
-				allErrs = append(allErrs, field.Invalid(portPath, port.Port, fmt.Sprintf("may not expose port %v externally since it is used by kubelet", ports.KubeletPort)))
-			}
-		}
 		if isHeadlessService(service) {
 			allErrs = append(allErrs, field.Invalid(specPath.Child("clusterIPs").Index(0), service.Spec.ClusterIPs[0], "may not be set to 'None' for LoadBalancer services"))
 		}

pkg/apis/core/validation/validation_test.go

@@ -15385,16 +15385,15 @@ func TestValidateServiceCreate(t *testing.T) {
 		},
 		numErrs: 0,
 	}, {
-		// For now we open firewalls, and its insecure if we open 10250, remove this
-		// when we have better protections in place.
-		name: "invalid port type=LoadBalancer",
+		// Remove the limitation on exposing port 10250 externally
+		name: "valid port type=LoadBalancer",
 		tweakSvc: func(s *core.Service) {
 			s.Spec.Type = core.ServiceTypeLoadBalancer
 			s.Spec.ExternalTrafficPolicy = core.ServiceExternalTrafficPolicyCluster
 			s.Spec.AllocateLoadBalancerNodePorts = utilpointer.Bool(true)
 			s.Spec.Ports = append(s.Spec.Ports, core.ServicePort{Name: "kubelet", Port: 10250, Protocol: "TCP", TargetPort: intstr.FromInt32(12345)})
 		},
-		numErrs: 1,
+		numErrs: 0,
 	}, {
 		name: "valid LoadBalancer source range annotation",
 		tweakSvc: func(s *core.Service) {