remove validation disallowing hostAlias with hostNetwork

pkg/api/validation/validation.go

@@ -2067,16 +2067,6 @@ func validateHostNetwork(hostNetwork bool, containers []api.Container, fldPath *
 	return allErrors
 }
 
-func validateHostNetworkNoHostAliases(hostNetwork bool, hostAliases []api.HostAlias, fldPath *field.Path) field.ErrorList {
-	allErrors := field.ErrorList{}
-	if hostNetwork {
-		if len(hostAliases) > 0 {
-			allErrors = append(allErrors, field.Forbidden(fldPath, "may not be set when `hostNetwork` is true"))
-		}
-	}
-	return allErrors
-}
-
 // validateImagePullSecrets checks to make sure the pull secrets are well
 // formed.  Right now, we only expect name to be set (it's the only field).  If
 // this ever changes and someone decides to set those fields, we'd like to
@@ -2620,7 +2610,6 @@ func ValidatePodSecurityContext(securityContext *api.PodSecurityContext, spec *a
 
 	if securityContext != nil {
 		allErrs = append(allErrs, validateHostNetwork(securityContext.HostNetwork, spec.Containers, specPath.Child("containers"))...)
-		allErrs = append(allErrs, validateHostNetworkNoHostAliases(securityContext.HostNetwork, spec.HostAliases, specPath)...)
 		if securityContext.FSGroup != nil {
 			for _, msg := range validation.IsValidGroupID(*securityContext.FSGroup) {
 				allErrs = append(allErrs, field.Invalid(fldPath.Child("fsGroup"), *(securityContext.FSGroup), msg))

pkg/api/validation/validation_test.go

@@ -3844,13 +3844,22 @@ func TestValidatePodSpec(t *testing.T) {
 			RestartPolicy: api.RestartPolicyAlways,
 			DNSPolicy:     api.DNSClusterFirst,
 		},
-		{ // Populate HostAliases with `foo.bar` hostnames .
+		{ // Populate HostAliases with `foo.bar` hostnames.
 			HostAliases:   []api.HostAlias{{IP: "12.34.56.78", Hostnames: []string{"host1.foo", "host2.bar"}}},
 			Volumes:       []api.Volume{{Name: "vol", VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}},
 			Containers:    []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
 			RestartPolicy: api.RestartPolicyAlways,
 			DNSPolicy:     api.DNSClusterFirst,
 		},
+		{ // Populate HostAliases with HostNetwork.
+			HostAliases: []api.HostAlias{{IP: "12.34.56.78", Hostnames: []string{"host1.foo", "host2.bar"}}},
+			Containers:  []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
+			SecurityContext: &api.PodSecurityContext{
+				HostNetwork: true,
+			},
+			RestartPolicy: api.RestartPolicyAlways,
+			DNSPolicy:     api.DNSClusterFirst,
+		},
 		{ // Populate PriorityClassName.
 			Volumes:           []api.Volume{{Name: "vol", VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}},
 			Containers:        []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
@@ -3923,12 +3932,6 @@ func TestValidatePodSpec(t *testing.T) {
 			RestartPolicy: api.RestartPolicyAlways,
 			DNSPolicy:     api.DNSClusterFirst,
 		},
-		"with hostNetwork and hostAliases": {
-			SecurityContext: &api.PodSecurityContext{
-				HostNetwork: true,
-			},
-			HostAliases: []api.HostAlias{{IP: "12.34.56.78", Hostnames: []string{"host1", "host2"}}},
-		},
 		"with hostAliases with invalid IP": {
 			SecurityContext: &api.PodSecurityContext{
 				HostNetwork: false,