Kubelet should have a max think time before auto resync

The sync frequency should be part of the syncLoop and resync no
less often than every X seconds.  The current implementation runs
even if a config update was delivered less than X seconds ago.

cmd/integration/integration.go

@@ -115,7 +115,6 @@ func startComponents(manifestURL string) (apiServerURL string) {
 	config.NewSourceURL(manifestURL, 5*time.Second, cfg1.Channel("url"))
 	myKubelet := kubelet.NewIntegrationTestKubelet(machineList[0], &fakeDocker1)
 	go util.Forever(func() { myKubelet.Run(cfg1.Updates()) }, 0)
-	go util.Forever(cfg1.Sync, 3*time.Second)
 	go util.Forever(func() {
 		kubelet.ListenAndServeKubeletServer(myKubelet, cfg1.Channel("http"), http.DefaultServeMux, "localhost", 10250)
 	}, 0)
@@ -127,7 +126,6 @@ func startComponents(manifestURL string) (apiServerURL string) {
 	config.NewSourceEtcd(config.EtcdKeyForHost(machineList[1]), etcdClient, 30*time.Second, cfg2.Channel("etcd"))
 	otherKubelet := kubelet.NewIntegrationTestKubelet(machineList[1], &fakeDocker2)
 	go util.Forever(func() { otherKubelet.Run(cfg2.Updates()) }, 0)
-	go util.Forever(cfg2.Sync, 3*time.Second)
 	go util.Forever(func() {
 		kubelet.ListenAndServeKubeletServer(otherKubelet, cfg2.Channel("http"), http.DefaultServeMux, "localhost", 10251)
 	}, 0)

cmd/kubelet/kubelet.go

@@ -148,16 +148,12 @@ func main() {
 		dockerClient,
 		cadvisorClient,
 		etcdClient,
-		*rootDirectory)
+		*rootDirectory,
+		*syncFrequency)
 
 	// start the kubelet
 	go util.Forever(func() { k.Run(cfg.Updates()) }, 0)
 
-	// resynchronize periodically
-	// TODO: make this part of PodConfig so that it is only delivered after syncFrequency has elapsed without
-	// an update
-	go util.Forever(cfg.Sync, *syncFrequency)
-
 	// start the kubelet server
 	if *enableServer {
 		go util.Forever(func() {

pkg/kubelet/kubelet.go

@@ -64,13 +64,15 @@ func NewMainKubelet(
 	dc DockerInterface,
 	cc CadvisorInterface,
 	ec tools.EtcdClient,
-	rd string) *Kubelet {
+	rd string,
+	ri time.Duration) *Kubelet {
 	return &Kubelet{
 		hostname:       hn,
 		dockerClient:   dc,
 		cadvisorClient: cc,
 		etcdClient:     ec,
 		rootDirectory:  rd,
+		resyncInterval: ri,
 		podWorkers:     newPodWorkers(),
 	}
 }
@@ -79,19 +81,21 @@ func NewMainKubelet(
 // TODO: add more integration tests, and expand parameter list as needed.
 func NewIntegrationTestKubelet(hn string, dc DockerInterface) *Kubelet {
 	return &Kubelet{
-		hostname:     hn,
-		dockerClient: dc,
-		dockerPuller: &FakeDockerPuller{},
-		podWorkers:   newPodWorkers(),
+		hostname:       hn,
+		dockerClient:   dc,
+		dockerPuller:   &FakeDockerPuller{},
+		resyncInterval: 3 * time.Second,
+		podWorkers:     newPodWorkers(),
 	}
 }
 
 // Kubelet is the main kubelet implementation.
 type Kubelet struct {
-	hostname      string
-	dockerClient  DockerInterface
-	rootDirectory string
-	podWorkers    podWorkers
+	hostname       string
+	dockerClient   DockerInterface
+	rootDirectory  string
+	podWorkers     podWorkers
+	resyncInterval time.Duration
 
 	// Optional, no events will be sent without it
 	etcdClient tools.EtcdClient
@@ -561,14 +565,15 @@ func filterHostPortConflicts(pods []Pod) []Pod {
 // no changes are seen to the configuration, will synchronize the last known desired
 // state every sync_frequency seconds. Never returns.
 func (kl *Kubelet) syncLoop(updates <-chan PodUpdate, handler SyncHandler) {
+	var pods []Pod
 	for {
-		var pods []Pod
 		select {
 		case u := <-updates:
 			switch u.Op {
 			case SET:
 				glog.Infof("Containers changed [%s]", kl.hostname)
 				pods = u.Pods
+				pods = filterHostPortConflicts(pods)
 
 			case UPDATE:
 				//TODO: implement updates of containers
@@ -578,10 +583,12 @@ func (kl *Kubelet) syncLoop(updates <-chan PodUpdate, handler SyncHandler) {
 			default:
 				panic("syncLoop does not support incremental changes")
 			}
+		case <-time.After(kl.resyncInterval):
+			if pods == nil {
+				continue
+			}
 		}
 
-		pods = filterHostPortConflicts(pods)
-
 		err := handler.SyncPods(pods)
 		if err != nil {
 			glog.Errorf("Couldn't sync containers : %v", err)