reduce hard code to avoid more mistakes

test/e2e/framework/service_util.go

@@ -40,6 +40,7 @@ import (
 	"k8s.io/client-go/util/retry"
 	api "k8s.io/kubernetes/pkg/apis/core"
 	"k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset"
+	"k8s.io/kubernetes/pkg/registry/core/service/portallocator"
 	testutils "k8s.io/kubernetes/test/utils"
 	imageutils "k8s.io/kubernetes/test/utils/image"
 
@@ -557,7 +558,7 @@ func (j *ServiceTestJig) ChangeServiceNodePortOrFail(namespace, name string, ini
 		service, err = j.UpdateService(namespace, name, func(s *v1.Service) {
 			s.Spec.Ports[0].NodePort = int32(newPort)
 		})
-		if err != nil && strings.Contains(err.Error(), "provided port is already allocated") {
+		if err != nil && strings.Contains(err.Error(), portallocator.ErrAllocated.Error()) {
 			Logf("tried nodePort %d, but it is in use, will try another", newPort)
 			continue
 		}