pr feedback

cluster/saltbase/salt/kube-dns/kubedns-rc.yaml.in

@@ -19,12 +19,9 @@ spec:
         version: v12
         kubernetes.io/cluster-service: "true"
     spec:
-{% if grains['cloud'] is defined and grains['cloud'] in [ 'vsphere', 'photon-controller' ] %}
-      hostNetwork: true
-{% endif %}
       containers:
       - name: kubedns
-        image: artfulcoder/kubedns-amd64:1.0
+        image: gcr.io/google_containers/kubedns-amd64:1.0
         resources:
           # TODO: Set memory limits when we've profiled the container for large
           # clusters, then set request = limit to keep this container in

cmd/kube-dns/app/options/options.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2014 The Kubernetes Authors All rights reserved.
+Copyright 2016 The Kubernetes Authors All rights reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -52,8 +52,8 @@ func (m clusterDomainVar) Set(v string) error {
 	v = strings.TrimSuffix(v, ".")
 	segments := strings.Split(v, ".")
 	for _, segment := range segments {
-		if !validation.IsDNS1123Label(segment) {
-			return fmt.Errorf("Not a valid DNS label")
+		if errs := validation.IsDNS1123Label(segment); len(errs) > 0 {
+			return fmt.Errorf("Not a valid DNS label. %v", errs)
 		}
 	}
 	if !strings.HasSuffix(v, ".") {

cmd/kube-dns/app/server.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2014 The Kubernetes Authors All rights reserved.
+Copyright 2016 The Kubernetes Authors All rights reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -24,7 +24,6 @@ import (
 	"syscall"
 
 	"github.com/golang/glog"
-
 	"github.com/skynetservices/skydns/metrics"
 	"github.com/skynetservices/skydns/server"
 	"k8s.io/kubernetes/cmd/kube-dns/app/options"
@@ -104,7 +103,13 @@ func (server *KubeDNSServer) setupHealthzHandlers() {
 		fmt.Fprintf(w, "ok\n")
 	})
 	http.HandleFunc("/cache", func(w http.ResponseWriter, req *http.Request) {
-		fmt.Fprint(w, server.kd.GetCacheAsJSON())
+		serializedJSON, err := server.kd.GetCacheAsJSON()
+		if err == nil {
+			fmt.Fprint(w, serializedJSON)
+		} else {
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprint(w, err)
+		}
 	})
 }
 

cmd/kube-dns/dns.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2014 The Kubernetes Authors All rights reserved.
+Copyright 2016 The Kubernetes Authors All rights reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -23,11 +23,9 @@ import (
 	"k8s.io/kubernetes/pkg/util"
 	"k8s.io/kubernetes/pkg/util/flag"
 	"k8s.io/kubernetes/pkg/version/verflag"
-	"runtime"
 )
 
 func main() {
-	runtime.GOMAXPROCS(runtime.NumCPU())
 	config := options.NewKubeDNSConfig()
 	config.AddFlags(pflag.CommandLine)
 

pkg/dns/dns.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2015 The Kubernetes Authors All rights reserved.
+Copyright 2016 The Kubernetes Authors All rights reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -19,13 +19,14 @@ package dns
 import (
 	"encoding/json"
 	"fmt"
-	"github.com/golang/glog"
 	"hash/fnv"
 	"net"
 	"strings"
+	"sync"
 	"time"
 
 	etcd "github.com/coreos/etcd/client"
+	"github.com/golang/glog"
 	skymsg "github.com/skynetservices/skydns/msg"
 	kapi "k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/api/endpoints"
@@ -47,20 +48,40 @@ const (
 	podSubdomain = "pod"
 
 	// Resync period for the kube controller loop.
-	resyncPeriod = 30 * time.Minute
+	resyncPeriod = 5 * time.Minute
 )
 
 type KubeDNS struct {
+	// kubeClient makes calls to API Server and registers calls with API Server
+	// to get Endpoints and Service objects.
 	kubeClient *kclient.Client
-	// DNS domain name.
+
+	// The domain for which this DNS Server is authoritative.
 	domain string
+
 	// A cache that contains all the endpoints in the system.
 	endpointsStore kcache.Store
+
 	// A cache that contains all the services in the system.
-	servicesStore     kcache.Store
-	cache             *TreeCache
-	domainPath        []string
-	eController       *kframework.Controller
+	servicesStore kcache.Store
+
+	// stores DNS records for the domain.
+	// A Records and SRV Records for (regular) services and headless Services.
+	cache *TreeCache
+
+	// caller is responsible for using the cacheLock before invoking methods on cache
+	// the cache is not thread-safe, and the caller can guarantee thread safety by using
+	// the cacheLock
+	cacheLock sync.RWMutex
+
+	// The domain for which this DNS Server is authoritative, in array format and reversed.
+	// e.g. if domain is "cluster.local", domainPath is []string{"local", "cluster"}
+	domainPath []string
+
+	// endpointsController  invokes registered callbacks when endpoints change.
+	endpointsController *kframework.Controller
+
+	// serviceController invokes registered callbacks when services change.
 	serviceController *kframework.Controller
 }
 
@@ -69,6 +90,7 @@ func NewKubeDNS(client *kclient.Client, domain string) *KubeDNS {
 		kubeClient: client,
 		domain:     domain,
 		cache:      NewTreeCache(),
+		cacheLock:  sync.RWMutex{},
 		domainPath: reverseArray(strings.Split(strings.TrimRight(domain, "."), ".")),
 	}
 	kd.setEndpointsStore()
@@ -77,11 +99,14 @@ func NewKubeDNS(client *kclient.Client, domain string) *KubeDNS {
 }
 
 func (kd *KubeDNS) Start() {
-	go kd.eController.Run(wait.NeverStop)
+	go kd.endpointsController.Run(wait.NeverStop)
 	go kd.serviceController.Run(wait.NeverStop)
 	// Wait synchronously for the Kubernetes service and add a DNS record for it.
-	// TODO (abshah) UNCOMMENT AFTER TEST COMPLETE
-	//kd.waitForKubernetesService()
+	// This ensures that the Start function returns only after having received Service objects
+	// from APIServer.
+	// TODO: we might not have to wait for kubernetes service specifically. We should just wait
+	// for a list operation to be complete from APIServer.
+	kd.waitForKubernetesService()
 }
 
 func (kd *KubeDNS) waitForKubernetesService() (svc *kapi.Service) {
@@ -101,9 +126,11 @@ func (kd *KubeDNS) waitForKubernetesService() (svc *kapi.Service) {
 	return
 }
 
-func (kd *KubeDNS) GetCacheAsJSON() string {
-	json, _ := kd.cache.Serialize("")
-	return json
+func (kd *KubeDNS) GetCacheAsJSON() (string, error) {
+	kd.cacheLock.RLock()
+	defer kd.cacheLock.RUnlock()
+	json, err := kd.cache.Serialize()
+	return json, err
 }
 
 func (kd *KubeDNS) setServicesStore() {
@@ -124,7 +151,7 @@ func (kd *KubeDNS) setServicesStore() {
 func (kd *KubeDNS) setEndpointsStore() {
 	// Returns a cache.ListWatch that gets all changes to endpoints.
 	endpointsWatch := kcache.NewListWatchFromClient(kd.kubeClient, "endpoints", kapi.NamespaceAll, kselector.Everything())
-	kd.endpointsStore, kd.eController = kframework.NewInformer(
+	kd.endpointsStore, kd.endpointsController = kframework.NewInformer(
 		endpointsWatch,
 		&kapi.Endpoints{},
 		resyncPeriod,
@@ -138,24 +165,35 @@ func (kd *KubeDNS) setEndpointsStore() {
 	)
 }
 
-func (kd *KubeDNS) newService(obj interface{}) {
+func assertIsService(obj interface{}) (*kapi.Service, bool) {
 	if service, ok := obj.(*kapi.Service); ok {
+		return service, ok
+	} else {
+		glog.Errorf("Type assertion failed! Expected 'Service', got %T", service)
+		return nil, ok
+	}
+}
+
+func (kd *KubeDNS) newService(obj interface{}) {
+	if service, ok := assertIsService(obj); ok {
 		// if ClusterIP is not set, a DNS entry should not be created
 		if !kapi.IsServiceIPSet(service) {
 			kd.newHeadlessService(service)
 			return
 		}
 		if len(service.Spec.Ports) == 0 {
-			glog.Info("Unexpected service with no ports, this should not have happend: %v", service)
+			glog.Warning("Unexpected service with no ports, this should not have happend: %v", service)
 		}
 		kd.newPortalService(service)
 	}
 }
 
 func (kd *KubeDNS) removeService(obj interface{}) {
-	if s, ok := obj.(*kapi.Service); ok {
+	if s, ok := assertIsService(obj); ok {
 		subCachePath := append(kd.domainPath, serviceSubdomain, s.Namespace, s.Name)
-		kd.cache.DeletePath(subCachePath...)
+		kd.cacheLock.Lock()
+		defer kd.cacheLock.Unlock()
+		kd.cache.deletePath(subCachePath...)
 	}
 }
 
@@ -194,7 +232,7 @@ func (kd *KubeDNS) getServiceFromEndpoints(e *kapi.Endpoints) (*kapi.Service, er
 		glog.V(1).Infof("could not find service for endpoint %q in namespace %q", e.Name, e.Namespace)
 		return nil, nil
 	}
-	if svc, ok := obj.(*kapi.Service); ok {
+	if svc, ok := assertIsService(obj); ok {
 		return svc, nil
 	}
 	return nil, fmt.Errorf("got a non service object in services store %v", obj)
@@ -203,18 +241,20 @@ func (kd *KubeDNS) getServiceFromEndpoints(e *kapi.Endpoints) (*kapi.Service, er
 func (kd *KubeDNS) newPortalService(service *kapi.Service) {
 	subCache := NewTreeCache()
 	recordValue, recordLabel := getSkyMsg(service.Spec.ClusterIP, 0)
-	subCache.SetEntry(recordLabel, recordValue)
+	subCache.setEntry(recordLabel, recordValue)
 
 	// Generate SRV Records
 	for i := range service.Spec.Ports {
 		port := &service.Spec.Ports[i]
 		if port.Name != "" && port.Protocol != "" {
 			srvValue := kd.generateSRVRecordValue(service, int(port.Port))
-			subCache.SetEntry(recordLabel, srvValue, "_"+strings.ToLower(string(port.Protocol)), "_"+port.Name)
+			subCache.setEntry(recordLabel, srvValue, "_"+strings.ToLower(string(port.Protocol)), "_"+port.Name)
 		}
 	}
 	subCachePath := append(kd.domainPath, serviceSubdomain, service.Namespace)
-	kd.cache.SetSubCache(service.Name, subCache, subCachePath...)
+	kd.cacheLock.Lock()
+	defer kd.cacheLock.Unlock()
+	kd.cache.setSubCache(service.Name, subCache, subCachePath...)
 }
 
 func (kd *KubeDNS) generateRecordsForHeadlessService(e *kapi.Endpoints, svc *kapi.Service) error {
@@ -233,18 +273,20 @@ func (kd *KubeDNS) generateRecordsForHeadlessService(e *kapi.Endpoints, svc *kap
 			if hostLabel, exists := getHostname(address, podHostnames); exists {
 				endpointName = hostLabel
 			}
-			subCache.SetEntry(endpointName, recordValue)
+			subCache.setEntry(endpointName, recordValue)
 			for portIdx := range e.Subsets[idx].Ports {
 				endpointPort := &e.Subsets[idx].Ports[portIdx]
 				if endpointPort.Name != "" && endpointPort.Protocol != "" {
 					srvValue := kd.generateSRVRecordValue(svc, int(endpointPort.Port), endpointName)
-					subCache.SetEntry(endpointName, srvValue, "_"+strings.ToLower(string(endpointPort.Protocol)), "_"+endpointPort.Name)
+					subCache.setEntry(endpointName, srvValue, "_"+strings.ToLower(string(endpointPort.Protocol)), "_"+endpointPort.Name)
 				}
 			}
 		}
 	}
 	subCachePath := append(kd.domainPath, serviceSubdomain, svc.Namespace)
-	kd.cache.SetSubCache(svc.Name, subCache, subCachePath...)
+	kd.cacheLock.Lock()
+	defer kd.cacheLock.Unlock()
+	kd.cache.setSubCache(svc.Name, subCache, subCachePath...)
 	return nil
 }
 
@@ -252,7 +294,7 @@ func getHostname(address *kapi.EndpointAddress, podHostnames map[string]endpoint
 	if len(address.Hostname) > 0 {
 		return address.Hostname, true
 	}
-	if hostRecord, exists := podHostnames[address.IP]; exists && validation.IsDNS1123Label(hostRecord.HostName) {
+	if hostRecord, exists := podHostnames[address.IP]; exists && len(validation.IsDNS1123Label(hostRecord.HostName)) == 0 {
 		return hostRecord.HostName, true
 	}
 	return "", false
@@ -272,12 +314,12 @@ func getPodHostnamesFromAnnotation(annotations map[string]string) (map[string]en
 	return hostnames, nil
 }
 
-func (kd *KubeDNS) generateSRVRecordValue(svc *kapi.Service, portNumber int, cNameLabels ...string) *skymsg.Service {
-	cName := strings.Join([]string{svc.Name, svc.Namespace, serviceSubdomain, kd.domain}, ".")
-	for _, cNameLabel := range cNameLabels {
-		cName = cNameLabel + "." + cName
+func (kd *KubeDNS) generateSRVRecordValue(svc *kapi.Service, portNumber int, labels ...string) *skymsg.Service {
+	host := strings.Join([]string{svc.Name, svc.Namespace, serviceSubdomain, kd.domain}, ".")
+	for _, cNameLabel := range labels {
+		host = cNameLabel + "." + host
 	}
-	recordValue, _ := getSkyMsg(cName, portNumber)
+	recordValue, _ := getSkyMsg(host, portNumber)
 	return recordValue
 }
 
@@ -312,9 +354,10 @@ func (kd *KubeDNS) Records(name string, exact bool) ([]skymsg.Service, error) {
 	segments := strings.Split(trimmed, ".")
 	path := reverseArray(segments)
 	if kd.isPodRecord(path) {
-		response, err := kd.getPodRecord(path)
+		ip, err := kd.getPodIP(path)
 		if err == nil {
-			return []skymsg.Service{*response}, nil
+			skyMsg, _ := getSkyMsg(ip, 0)
+			return []skymsg.Service{*skyMsg}, nil
 		}
 		return nil, err
 	}
@@ -324,15 +367,17 @@ func (kd *KubeDNS) Records(name string, exact bool) ([]skymsg.Service, error) {
 		if key == "" {
 			return []skymsg.Service{}, nil
 		}
-		if record, ok := kd.cache.GetEntry(key, path[:len(path)-1]...); ok {
+		kd.cacheLock.RLock()
+		defer kd.cacheLock.RUnlock()
+		if record, ok := kd.cache.getEntry(key, path[:len(path)-1]...); ok {
 			return []skymsg.Service{*(record.(*skymsg.Service))}, nil
 		}
 		return nil, etcd.Error{Code: etcd.ErrorCodeKeyNotFound}
 	}
 
-	// tmp, _ := kd.cache.Serialize("")
-	// glog.Infof("Searching path:%q, %v", path, tmp)
-	records := kd.cache.GetValuesForPathWithRegex(path...)
+	kd.cacheLock.RLock()
+	defer kd.cacheLock.RUnlock()
+	records := kd.cache.getValuesForPathWithWildcards(path...)
 	retval := []skymsg.Service{}
 	for _, val := range records {
 		retval = append(retval, *(val.(*skymsg.Service)))
@@ -350,7 +395,7 @@ func (kd *KubeDNS) ReverseRecord(name string) (*skymsg.Service, error) {
 	segments := strings.Split(strings.TrimRight(name, "."), ".")
 
 	for _, k := range segments {
-		if k == "*" || k == "any" {
+		if k == "*" {
 			return nil, fmt.Errorf("reverse can not contain wildcards")
 		}
 	}
@@ -374,20 +419,13 @@ func (kd *KubeDNS) isPodRecord(path []string) bool {
 	return true
 }
 
-func (kd *KubeDNS) getPodRecord(path []string) (*skymsg.Service, error) {
+func (kd *KubeDNS) getPodIP(path []string) (string, error) {
 	ipStr := path[len(path)-1]
 	ip := strings.Replace(ipStr, "-", ".", -1)
 	if parsed := net.ParseIP(ip); parsed != nil {
-		msg := &skymsg.Service{
-			Host:     ip,
-			Port:     0,
-			Priority: 10,
-			Weight:   10,
-			Ttl:      30,
-		}
-		return msg, nil
+		return ip, nil
 	}
-	return nil, fmt.Errorf("Invalid IP Address %v", ip)
+	return "", fmt.Errorf("Invalid IP Address %v", ip)
 }
 
 // Returns record in a format that SkyDNS understands.

pkg/dns/dns_test.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2015 The Kubernetes Authors All rights reserved.
+Copyright 2016 The Kubernetes Authors All rights reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -18,7 +18,9 @@ package dns
 
 import (
 	"fmt"
+	"net"
 	"strings"
+	"sync"
 	"testing"
 
 	skymsg "github.com/skynetservices/skydns/msg"
@@ -26,16 +28,12 @@ import (
 	"github.com/stretchr/testify/require"
 	kapi "k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/client/cache"
-	"net"
 )
 
 const (
-	testDomain       = "cluster.local."
-	basePath         = "/skydns/local/cluster"
-	serviceSubDomain = "svc"
-	podSubDomain     = "pod"
-	testService      = "testservice"
-	testNamespace    = "default"
+	testDomain    = "cluster.local."
+	testService   = "testservice"
+	testNamespace = "default"
 )
 
 func newKubeDNS() *KubeDNS {
@@ -44,6 +42,7 @@ func newKubeDNS() *KubeDNS {
 		endpointsStore: cache.NewStore(cache.MetaNamespaceKeyFunc),
 		servicesStore:  cache.NewStore(cache.MetaNamespaceKeyFunc),
 		cache:          NewTreeCache(),
+		cacheLock:      sync.RWMutex{},
 		domainPath:     reverseArray(strings.Split(strings.TrimRight(testDomain, "."), ".")),
 	}
 	return kd
@@ -53,7 +52,6 @@ func TestPodDns(t *testing.T) {
 	const (
 		testPodIP      = "1.2.3.4"
 		sanitizedPodIP = "1-2-3-4"
-		testPodName    = "testPod"
 	)
 	kd := newKubeDNS()
 
@@ -240,9 +238,7 @@ func newEndpoints(service *kapi.Service, subsets ...kapi.EndpointSubset) *kapi.E
 		Subsets:    []kapi.EndpointSubset{},
 	}
 
-	for _, subset := range subsets {
-		endpoints.Subsets = append(endpoints.Subsets, subset)
-	}
+	endpoints.Subsets = append(endpoints.Subsets, subsets...)
 	return &endpoints
 }
 
@@ -310,7 +306,7 @@ func assertCNameRecordsMatchEndpointIPs(t *testing.T, kd *KubeDNS, e []kapi.Endp
 	assert.Equal(t, len(e), len(records), "unexpected record count")
 	for _, record := range records {
 		_, found := endpoints[getIPForCName(t, kd, record.Host)]
-		assert.True(t, found, "Did not endpoint with address:%s", record.Host)
+		assert.True(t, found, "Did not find endpoint with address:%s", record.Host)
 	}
 }
 
@@ -342,20 +338,18 @@ func assertNoSRVForNamedPort(t *testing.T, kd *KubeDNS, s *kapi.Service, portNam
 }
 
 func assertNoDNSForClusterIP(t *testing.T, kd *KubeDNS, s *kapi.Service) {
-	records, err := kd.Records(getServiceFQDN(kd, s), false)
-	require.Error(t, err)
-	assert.Equal(t, 0, len(records))
+	serviceFQDN := getServiceFQDN(kd, s)
+	queries := getEquivalentQueries(serviceFQDN, s.Namespace)
+	for _, query := range queries {
+		records, err := kd.Records(query, false)
+		require.Error(t, err)
+		assert.Equal(t, 0, len(records))
+	}
 }
 
 func assertDNSForClusterIP(t *testing.T, kd *KubeDNS, s *kapi.Service) {
 	serviceFQDN := getServiceFQDN(kd, s)
-	queries := []string{
-		serviceFQDN,
-		strings.Replace(serviceFQDN, ".svc.", ".*.", 1),
-		strings.Replace(serviceFQDN, s.Namespace, "*", 1),
-		strings.Replace(strings.Replace(serviceFQDN, s.Namespace, "*", 1), ".svc.", ".*.", 1),
-		"*." + serviceFQDN,
-	}
+	queries := getEquivalentQueries(serviceFQDN, s.Namespace)
 	for _, query := range queries {
 		records, err := kd.Records(query, false)
 		require.NoError(t, err)
@@ -364,12 +358,22 @@ func assertDNSForClusterIP(t *testing.T, kd *KubeDNS, s *kapi.Service) {
 	}
 }
 
+func getEquivalentQueries(serviceFQDN, namespace string) []string {
+	return []string{
+		serviceFQDN,
+		strings.Replace(serviceFQDN, ".svc.", ".*.", 1),
+		strings.Replace(serviceFQDN, namespace, "*", 1),
+		strings.Replace(strings.Replace(serviceFQDN, namespace, "*", 1), ".svc.", ".*.", 1),
+		"*." + serviceFQDN,
+	}
+}
+
 func getServiceFQDN(kd *KubeDNS, s *kapi.Service) string {
 	return fmt.Sprintf("%s.%s.svc.%s", s.Name, s.Namespace, kd.domain)
 }
 
 func getEndpointsFQDN(kd *KubeDNS, e *kapi.Endpoints) string {
-	return fmt.Sprintf("%s.%s.svc.%s", e.ObjectMeta.Name, e.ObjectMeta.Namespace, kd.domain)
+	return fmt.Sprintf("%s.%s.svc.%s", e.Name, e.Namespace, kd.domain)
 }
 
 func getSRVFQDN(kd *KubeDNS, s *kapi.Service, portName string) string {

pkg/dns/treecache.go

@@ -1,5 +1,5 @@
 /*
-Copyright 2015 The Kubernetes Authors All rights reserved.
+Copyright 2016 The Kubernetes Authors All rights reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -18,136 +18,65 @@ package dns
 
 import (
 	"bytes"
-	"crypto/md5"
 	"encoding/json"
-	"fmt"
-	"io/ioutil"
-	"os"
-	"path"
-	"reflect"
 	"strings"
-	"sync"
 )
 
-const (
-	dataFile = "data.dat"
-	crcFile  = "data.crc"
-)
-
-type object interface{}
-
 type TreeCache struct {
 	ChildNodes map[string]*TreeCache
 	Entries    map[string]interface{}
-	m          *sync.RWMutex
 }
 
 func NewTreeCache() *TreeCache {
 	return &TreeCache{
 		ChildNodes: make(map[string]*TreeCache),
 		Entries:    make(map[string]interface{}),
-		m:          &sync.RWMutex{},
 	}
 }
 
-func Deserialize(dir string) (*TreeCache, error) {
-	b, err := ioutil.ReadFile(path.Join(dir, dataFile))
-	if err != nil {
-		return nil, err
-	}
-	var hash []byte
-	hash, err = ioutil.ReadFile(path.Join(dir, crcFile))
-	if err != nil {
-		return nil, err
-	}
-	if !reflect.DeepEqual(hash, getMD5(b)) {
-		return nil, fmt.Errorf("Checksum failed")
-	}
-
-	var cache TreeCache
-	err = json.Unmarshal(b, &cache)
-	if err != nil {
-		return nil, err
-	}
-	cache.m = &sync.RWMutex{}
-	return &cache, nil
-}
-
-func (cache *TreeCache) Serialize(dir string) (string, error) {
-	cache.m.RLock()
-	defer cache.m.RUnlock()
+func (cache *TreeCache) Serialize() (string, error) {
 	b, err := json.Marshal(cache)
 	if err != nil {
 		return "", err
 	}
 
-	if len(dir) == 0 {
-		var prettyJSON bytes.Buffer
-		err = json.Indent(&prettyJSON, b, "", "\t")
+	var prettyJSON bytes.Buffer
+	err = json.Indent(&prettyJSON, b, "", "\t")
 
-		if err != nil {
-			return "", err
-		}
-		return string(prettyJSON.Bytes()), nil
-	}
-	if err := ensureDir(dir, os.FileMode(0755)); err != nil {
+	if err != nil {
 		return "", err
 	}
-	if err := ioutil.WriteFile(path.Join(dir, dataFile), b, 0644); err != nil {
-		return "", err
-	}
-	if err := ioutil.WriteFile(path.Join(dir, crcFile), getMD5(b), 0644); err != nil {
-		return "", err
-	}
-	return string(b), nil
+	return string(prettyJSON.Bytes()), nil
 }
 
-func (cache *TreeCache) SetEntry(key string, val interface{}, path ...string) {
-	cache.m.Lock()
-	defer cache.m.Unlock()
+func (cache *TreeCache) setEntry(key string, val interface{}, path ...string) {
 	node := cache.ensureChildNode(path...)
 	node.Entries[key] = val
 }
 
-func (cache *TreeCache) ReplaceEntries(entries map[string]interface{}, path ...string) {
-	cache.m.Lock()
-	defer cache.m.Unlock()
-	node := cache.ensureChildNode(path...)
-	node.Entries = make(map[string]interface{})
-	for key, val := range entries {
-		node.Entries[key] = val
-	}
-}
-
-func (cache *TreeCache) GetSubCache(path ...string) *TreeCache {
+func (cache *TreeCache) getSubCache(path ...string) *TreeCache {
 	childCache := cache
 	for _, subpath := range path {
 		childCache = childCache.ChildNodes[subpath]
 		if childCache == nil {
-			return childCache
+			return nil
 		}
 	}
 	return childCache
 }
 
-func (cache *TreeCache) SetSubCache(key string, subCache *TreeCache, path ...string) {
-	cache.m.Lock()
-	defer cache.m.Unlock()
+func (cache *TreeCache) setSubCache(key string, subCache *TreeCache, path ...string) {
 	node := cache.ensureChildNode(path...)
 	node.ChildNodes[key] = subCache
 }
 
-func (cache *TreeCache) GetEntry(key string, path ...string) (interface{}, bool) {
-	cache.m.RLock()
-	defer cache.m.RUnlock()
-	childNode := cache.GetSubCache(path...)
+func (cache *TreeCache) getEntry(key string, path ...string) (interface{}, bool) {
+	childNode := cache.getSubCache(path...)
 	val, ok := childNode.Entries[key]
 	return val, ok
 }
 
-func (cache *TreeCache) GetValuesForPathWithRegex(path ...string) []interface{} {
-	cache.m.RLock()
-	defer cache.m.RUnlock()
+func (cache *TreeCache) getValuesForPathWithWildcards(path ...string) []interface{} {
 	retval := []interface{}{}
 	nodesToExplore := []*TreeCache{cache}
 	for idx, subpath := range path {
@@ -155,7 +84,7 @@ func (cache *TreeCache) GetValuesForPathWithRegex(path ...string) []interface{}
 		if idx == len(path)-1 {
 			// if path ends on an entry, instead of a child node, add the entry
 			for _, node := range nodesToExplore {
-				if subpath == "*" || subpath == "any" {
+				if subpath == "*" {
 					nextNodesToExplore = append(nextNodesToExplore, node)
 				} else {
 					if val, ok := node.Entries[subpath]; ok {
@@ -172,7 +101,7 @@ func (cache *TreeCache) GetValuesForPathWithRegex(path ...string) []interface{}
 			break
 		}
 
-		if subpath == "*" || subpath == "any" {
+		if subpath == "*" {
 			for _, node := range nodesToExplore {
 				for subkey, subnode := range node.ChildNodes {
 					if !strings.HasPrefix(subkey, "_") {
@@ -200,26 +129,11 @@ func (cache *TreeCache) GetValuesForPathWithRegex(path ...string) []interface{}
 	return retval
 }
 
-func (cache *TreeCache) GetEntries(recursive bool, path ...string) []interface{} {
-	cache.m.RLock()
-	defer cache.m.RUnlock()
-	childNode := cache.GetSubCache(path...)
-	if childNode == nil {
-		return nil
-	}
-
-	retval := [][]interface{}{{}}
-	childNode.appendValues(recursive, retval)
-	return retval[0]
-}
-
-func (cache *TreeCache) DeletePath(path ...string) bool {
+func (cache *TreeCache) deletePath(path ...string) bool {
 	if len(path) == 0 {
 		return false
 	}
-	cache.m.Lock()
-	defer cache.m.Unlock()
-	if parentNode := cache.GetSubCache(path[:len(path)-1]...); parentNode != nil {
+	if parentNode := cache.getSubCache(path[:len(path)-1]...); parentNode != nil {
 		if _, ok := parentNode.ChildNodes[path[len(path)-1]]; ok {
 			delete(parentNode.ChildNodes, path[len(path)-1])
 			return true
@@ -228,10 +142,8 @@ func (cache *TreeCache) DeletePath(path ...string) bool {
 	return false
 }
 
-func (tn *TreeCache) DeleteEntry(key string, path ...string) bool {
-	tn.m.Lock()
-	defer tn.m.Unlock()
-	childNode := tn.GetSubCache(path...)
+func (cache *TreeCache) deleteEntry(key string, path ...string) bool {
+	childNode := cache.getSubCache(path...)
 	if childNode == nil {
 		return false
 	}
@@ -242,22 +154,22 @@ func (tn *TreeCache) DeleteEntry(key string, path ...string) bool {
 	return false
 }
 
-func (tn *TreeCache) appendValues(recursive bool, ref [][]interface{}) {
-	for _, value := range tn.Entries {
+func (cache *TreeCache) appendValues(recursive bool, ref [][]interface{}) {
+	for _, value := range cache.Entries {
 		ref[0] = append(ref[0], value)
 	}
 	if recursive {
-		for _, node := range tn.ChildNodes {
+		for _, node := range cache.ChildNodes {
 			node.appendValues(recursive, ref)
 		}
 	}
 }
 
-func (tn *TreeCache) ensureChildNode(path ...string) *TreeCache {
-	childNode := tn
+func (cache *TreeCache) ensureChildNode(path ...string) *TreeCache {
+	childNode := cache
 	for _, subpath := range path {
-		newNode := childNode.ChildNodes[subpath]
-		if newNode == nil {
+		newNode, ok := childNode.ChildNodes[subpath]
+		if !ok {
 			newNode = NewTreeCache()
 			childNode.ChildNodes[subpath] = newNode
 		}
@@ -266,47 +178,70 @@ func (tn *TreeCache) ensureChildNode(path ...string) *TreeCache {
 	return childNode
 }
 
-func ensureDir(path string, perm os.FileMode) error {
-	s, err := os.Stat(path)
-	if err != nil || !s.IsDir() {
-		return os.Mkdir(path, perm)
-	}
-	return nil
-}
+// unused function. keeping it around in commented-fashion
+// in the future, we might need some form of this function so that
+// we can serialize to a file in a mounted empty dir..
+//const (
+//	dataFile = "data.dat"
+//	crcFile  = "data.crc"
+//)
+//func (cache *TreeCache) Serialize(dir string) (string, error) {
+//	cache.m.RLock()
+//	defer cache.m.RUnlock()
+//	b, err := json.Marshal(cache)
+//	if err != nil {
+//		return "", err
+//	}
+//
+//	if err := ensureDir(dir, os.FileMode(0755)); err != nil {
+//		return "", err
+//	}
+//	if err := ioutil.WriteFile(path.Join(dir, dataFile), b, 0644); err != nil {
+//		return "", err
+//	}
+//	if err := ioutil.WriteFile(path.Join(dir, crcFile), getMD5(b), 0644); err != nil {
+//		return "", err
+//	}
+//	return string(b), nil
+//}
 
-func getMD5(b []byte) []byte {
-	h := md5.New()
-	h.Write(b)
-	return []byte(fmt.Sprintf("%x", h.Sum(nil)))
-}
+//func ensureDir(path string, perm os.FileMode) error {
+//	s, err := os.Stat(path)
+//	if err != nil || !s.IsDir() {
+//		return os.Mkdir(path, perm)
+//	}
+//	return nil
+//}
 
-func main() {
-	root := NewTreeCache()
-	fmt.Println("Adding Entries")
-	root.SetEntry("k", "v")
-	root.SetEntry("foo", "bar", "local")
-	root.SetEntry("foo1", "bar1", "local", "cluster")
+//func getMD5(b []byte) []byte {
+//	h := md5.New()
+//	h.Write(b)
+//	return []byte(fmt.Sprintf("%x", h.Sum(nil)))
+//}
 
-	fmt.Println("Fetching Entries")
-	for _, entry := range root.GetEntries(true, "local") {
-		fmt.Printf("%s\n", entry)
-	}
-
-	fmt.Println("Serializing")
-	if _, err := root.Serialize("./foo"); err != nil {
-		fmt.Printf("Serialization Error:  %v,\n", err)
-		return
-	}
-
-	fmt.Println("Deserializing")
-	tn, err := Deserialize("./foo")
-	if err != nil {
-		fmt.Printf("Deserialization Error: %v\n", err)
-		return
-	}
-
-	fmt.Println("Fetching Entries")
-	for _, entry := range tn.GetEntries(true, "local") {
-		fmt.Printf("%s\n", entry)
-	}
-}
+// unused function. keeping it around in commented-fashion
+// in the future, we might need some form of this function so that
+// we can restart kube-dns, deserialize the tree and have a cache
+// without having to wait for kube-dns to reach out to API server.
+//func Deserialize(dir string) (*TreeCache, error) {
+//	b, err := ioutil.ReadFile(path.Join(dir, dataFile))
+//	if err != nil {
+//		return nil, err
+//	}
+//
+//	hash, err := ioutil.ReadFile(path.Join(dir, crcFile))
+//	if err != nil {
+//		return nil, err
+//	}
+//	if !reflect.DeepEqual(hash, getMD5(b)) {
+//		return nil, fmt.Errorf("Checksum failed")
+//	}
+//
+//	var cache TreeCache
+//	err = json.Unmarshal(b, &cache)
+//	if err != nil {
+//		return nil, err
+//	}
+//	cache.m = &sync.RWMutex{}
+//	return &cache, nil
+//}