Refactor kubelet, standalone k8s and integration test to all use the same code.

cmd/integration/integration.go

@@ -23,7 +23,6 @@ import (
 	"net"
 	"net/http"
 	"net/http/httptest"
-	"os"
 	"reflect"
 	"runtime"
 	"strconv"
@@ -40,12 +39,11 @@ import (
 	minionControllerPkg "github.com/GoogleCloudPlatform/kubernetes/pkg/cloudprovider/controller"
 	replicationControllerPkg "github.com/GoogleCloudPlatform/kubernetes/pkg/controller"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/health"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/config"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/dockertools"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/master"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/service"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/standalone"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/wait"
 	"github.com/GoogleCloudPlatform/kubernetes/plugin/pkg/scheduler"
@@ -56,6 +54,7 @@ import (
 )
 
 const testRootDir = "/tmp/kubelet"
+const testRootDir2 = "/tmp/kubelet2"
 
 var (
 	fakeDocker1, fakeDocker2 dockertools.FakeDockerClient
@@ -187,26 +186,11 @@ func startComponents(manifestURL string) (apiServerURL string) {
 	minionController.Run(10 * time.Second)
 
 	// Kubelet (localhost)
-	os.MkdirAll(testRootDir, 0750)
+	standalone.SimpleRunKubelet(etcdClient, &fakeDocker1, machineList[0], testRootDir, manifestURL, "127.0.0.1", 10250)
-	cfg1 := config.NewPodConfig(config.PodConfigNotificationSnapshotAndUpdates)
-	config.NewSourceEtcd(config.EtcdKeyForHost(machineList[0]), etcdClient, cfg1.Channel("etcd"))
-	config.NewSourceURL(manifestURL, 5*time.Second, cfg1.Channel("url"))
-	myKubelet := kubelet.NewIntegrationTestKubelet(machineList[0], testRootDir, &fakeDocker1)
-	go util.Forever(func() { myKubelet.Run(cfg1.Updates()) }, 0)
-	go util.Forever(func() {
-		kubelet.ListenAndServeKubeletServer(myKubelet, cfg1.Channel("http"), net.ParseIP("127.0.0.1"), 10250, true)
-	}, 0)
-
 	// Kubelet (machine)
 	// Create a second kubelet so that the guestbook example's two redis slaves both
 	// have a place they can schedule.
-	cfg2 := config.NewPodConfig(config.PodConfigNotificationSnapshotAndUpdates)
+	standalone.SimpleRunKubelet(etcdClient, &fakeDocker2, machineList[1], testRootDir2, "", "127.0.0.1", 10251)
-	config.NewSourceEtcd(config.EtcdKeyForHost(machineList[1]), etcdClient, cfg2.Channel("etcd"))
-	otherKubelet := kubelet.NewIntegrationTestKubelet(machineList[1], testRootDir, &fakeDocker2)
-	go util.Forever(func() { otherKubelet.Run(cfg2.Updates()) }, 0)
-	go util.Forever(func() {
-		kubelet.ListenAndServeKubeletServer(otherKubelet, cfg2.Channel("http"), net.ParseIP("127.0.0.1"), 10251, true)
-	}, 0)
 
 	return apiServer.URL
 }

cmd/kubelet/kubelet.go

@@ -24,28 +24,15 @@ import (
 	"flag"
 	"math/rand"
 	"net"
-	"net/http"
-	"os"
-	"os/exec"
-	"path"
-	"strings"
 	"time"
 
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/client/record"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/clientauth"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/health"
 	_ "github.com/GoogleCloudPlatform/kubernetes/pkg/healthz"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet"
-	kconfig "github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/config"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/master/ports"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/standalone"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/version/verflag"
-	"github.com/coreos/go-etcd/etcd"
-	"github.com/fsouza/go-dockerclient"
 	"github.com/golang/glog"
-	cadvisor "github.com/google/cadvisor/client"
 )
 
 const defaultRootDir = "/var/lib/kubelet"
@@ -82,52 +69,15 @@ func init() {
 	flag.Var(&apiServerList, "api_servers", "List of Kubernetes API servers to publish events to. (ip:port), comma separated.")
 }
 
-func getDockerEndpoint() string {
+func setupRunOnce() {
-	var endpoint string
+	if *runonce {
-	if len(*dockerEndpoint) > 0 {
+		if len(etcdServerList) > 0 {
-		endpoint = *dockerEndpoint
+			glog.Fatalf("invalid option: --runonce and --etcd_servers are mutually exclusive")
-	} else if len(os.Getenv("DOCKER_HOST")) > 0 {
+		}
-		endpoint = os.Getenv("DOCKER_HOST")
+		if *enableServer {
-	} else {
+			glog.Infof("--runonce is set, disabling server")
-		endpoint = "unix:///var/run/docker.sock"
+			*enableServer = false
-	}
-	glog.Infof("Connecting to docker on %s", endpoint)
-
-	return endpoint
-}
-
-func getHostname() string {
-	hostname := []byte(*hostnameOverride)
-	if string(hostname) == "" {
-		// Note: We use exec here instead of os.Hostname() because we
-		// want the FQDN, and this is the easiest way to get it.
-		fqdn, err := exec.Command("hostname", "-f").Output()
-		if err != nil {
-			glog.Fatalf("Couldn't determine hostname: %v", err)
 		}
-		hostname = fqdn
-	}
-	return strings.TrimSpace(string(hostname))
-}
-
-func getApiserverClient() (*client.Client, error) {
-	authInfo, err := clientauth.LoadFromFile(*authPath)
-	if err != nil {
-		return nil, err
-	}
-	clientConfig, err := authInfo.MergeWithConfig(client.Config{})
-	if err != nil {
-		return nil, err
-	}
-	// TODO: adapt Kube client to support LB over several servers
-	if len(apiServerList) > 1 {
-		glog.Infof("Mulitple api servers specified.  Picking first one")
-	}
-	clientConfig.Host = apiServerList[0]
-	if c, err := client.New(&clientConfig); err != nil {
-		return nil, err
-	} else {
-		return c, nil
 	}
 }
 
@@ -139,147 +89,34 @@ func main() {
 
 	verflag.PrintAndExitIfRequested()
 
-	if *runonce {
+	setupRunOnce()
-		exclusiveFlag := "invalid option: --runonce and %s are mutually exclusive"
+
-		if len(etcdServerList) > 0 {
+	kcfg := standalone.KubeletConfig{
-			glog.Fatalf(exclusiveFlag, "--etcd_servers")
+		Address:                 address,
-		}
+		AuthPath:                *authPath,
-		if *enableServer {
+		ApiServerList:           apiServerList,
-			glog.Infof("--runonce is set, disabling server")
+		AllowPrivileged:         *allowPrivileged,
-			*enableServer = false
+		HostnameOverride:        *hostnameOverride,
-		}
+		RootDirectory:           *rootDirectory,
-	}
+		ConfigFile:              *config,
-
+		ManifestURL:             *manifestURL,
-	etcd.SetLogger(util.NewLogger("etcd "))
+		FileCheckFrequency:      *fileCheckFrequency,
-
+		HttpCheckFrequency:      *httpCheckFrequency,
-	// Make an API client if possible.
+		NetworkContainerImage:   *networkContainerImage,
-	if len(apiServerList) < 1 {
+		SyncFrequency:           *syncFrequency,
-		glog.Info("No api servers specified.")
+		RegistryPullQPS:         *registryPullQPS,
-	} else {
+		RegistryBurst:           *registryBurst,
-		if apiClient, err := getApiserverClient(); err != nil {
+		MinimumGCAge:            *minimumGCAge,
-			glog.Errorf("Unable to make apiserver client: %v", err)
+		MaxContainerCount:       *maxContainerCount,
-		} else {
+		Runonce:                 *runonce,
-			// Send events to APIserver if there is a client.
+		Port:                    *port,
-			glog.Infof("Sending events to APIserver.")
+		EnableServer:            *enableServer,
-			record.StartRecording(apiClient.Events(""), "kubelet")
+		EnableDebuggingHandlers: *enableDebuggingHandlers,
-		}
+		DockerClient:            kubelet.ConnectToDockerOrDie(*dockerEndpoint),
-	}
+		EtcdClient:              kubelet.EtcdClientOrDie(etcdServerList, *etcdConfigFile),
-
-	// Log the events locally too.
-	record.StartLogging(glog.Infof)
-
-	capabilities.Initialize(capabilities.Capabilities{
-		AllowPrivileged: *allowPrivileged,
-	})
-
-	dockerClient, err := docker.NewClient(getDockerEndpoint())
-	if err != nil {
-		glog.Fatal("Couldn't connect to docker.")
-	}
-
-	hostname := getHostname()
-
-	if *rootDirectory == "" {
-		glog.Fatal("Invalid root directory path.")
-	}
-	*rootDirectory = path.Clean(*rootDirectory)
-	if err := os.MkdirAll(*rootDirectory, 0750); err != nil {
-		glog.Fatalf("Error creating root directory: %v", err)
-	}
-
-	// source of all configuration
-	cfg := kconfig.NewPodConfig(kconfig.PodConfigNotificationSnapshotAndUpdates)
-
-	// define file config source
-	if *config != "" {
-		kconfig.NewSourceFile(*config, *fileCheckFrequency, cfg.Channel("file"))
-	}
-
-	// define url config source
-	if *manifestURL != "" {
-		kconfig.NewSourceURL(*manifestURL, *httpCheckFrequency, cfg.Channel("http"))
-	}
-
-	// define etcd config source and initialize etcd client
-	var etcdClient *etcd.Client
-	if len(etcdServerList) > 0 {
-		etcdClient = etcd.NewClient(etcdServerList)
-	} else if *etcdConfigFile != "" {
-		var err error
-		etcdClient, err = etcd.NewClientFromFile(*etcdConfigFile)
-		if err != nil {
-			glog.Fatalf("Error with etcd config file: %v", err)
-		}
-	}
-
-	if etcdClient != nil {
-		glog.Infof("Watching for etcd configs at %v", etcdClient.GetCluster())
-		kconfig.NewSourceEtcd(kconfig.EtcdKeyForHost(hostname), etcdClient, cfg.Channel("etcd"))
-	}
-
-	// TODO: block until all sources have delivered at least one update to the channel, or break the sync loop
-	// up into "per source" synchronizations
-
-	k := kubelet.NewMainKubelet(
-		getHostname(),
-		dockerClient,
-		etcdClient,
-		*rootDirectory,
-		*networkContainerImage,
-		*syncFrequency,
-		float32(*registryPullQPS),
-		*registryBurst,
-		*minimumGCAge,
-		*maxContainerCount)
-
-	k.BirthCry()
-
-	go func() {
-		util.Forever(func() {
-			err := k.GarbageCollectContainers()
-			if err != nil {
-				glog.Errorf("Garbage collect failed: %v", err)
-			}
-		}, time.Minute*1)
-	}()
-
-	go func() {
-		defer util.HandleCrash()
-		// TODO: Monitor this connection, reconnect if needed?
-		glog.V(1).Infof("Trying to create cadvisor client.")
-		cadvisorClient, err := cadvisor.NewClient("http://127.0.0.1:4194")
-		if err != nil {
-			glog.Errorf("Error on creating cadvisor client: %v", err)
-			return
-		}
-		glog.V(1).Infof("Successfully created cadvisor client.")
-		k.SetCadvisorClient(cadvisorClient)
-	}()
-
-	// TODO: These should probably become more plugin-ish: register a factory func
-	// in each checker's init(), iterate those here.
-	health.AddHealthChecker(health.NewExecHealthChecker(k))
-	health.AddHealthChecker(health.NewHTTPHealthChecker(&http.Client{}))
-	health.AddHealthChecker(&health.TCPHealthChecker{})
-
-	// process pods and exit.
-	if *runonce {
-		if _, err := k.RunOnce(cfg.Updates()); err != nil {
-			glog.Fatalf("--runonce failed: %v", err)
-		}
-		return
-	}
-
-	// start the kubelet
-	go util.Forever(func() { k.Run(cfg.Updates()) }, 0)
-
-	// start the kubelet server
-	if *enableServer {
-		go util.Forever(func() {
-			kubelet.ListenAndServeKubeletServer(k, cfg.Channel("http"), net.IP(address), *port, *enableDebuggingHandlers)
-		}, 0)
 	}
 
+	standalone.RunKubelet(&kcfg)
 	// runs forever
 	select {}
 }

cmd/kubernetes/kubernetes.go

@@ -27,6 +27,7 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/testapi"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/standalone"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
@@ -50,7 +51,9 @@ func startComponents(etcdClient tools.EtcdClient, cl *client.Client, addr string
 	standalone.RunApiServer(cl, etcdClient, addr, port)
 	standalone.RunScheduler(cl)
 	standalone.RunControllerManager(machineList, cl, *nodeMilliCPU, *nodeMemory)
-	standalone.RunKubelet(etcdClient, machineList[0], *dockerEndpoint)
+
+	dockerClient := kubelet.ConnectToDockerOrDie(*dockerEndpoint)
+	standalone.SimpleRunKubelet(etcdClient, dockerClient, machineList[0], "/tmp/kubernetes", "", "127.0.0.1", 10250)
 }
 
 func newApiClient(addr string, port int) *client.Client {

pkg/kubelet/util.go

@@ -0,0 +1,187 @@
+/*
+Copyright 2014 Google Inc. 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.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubelet
+
+import (
+	"net/http"
+	"os"
+	"os/exec"
+	"path"
+	"strings"
+	"time"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client/record"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/clientauth"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/health"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/coreos/go-etcd/etcd"
+	"github.com/fsouza/go-dockerclient"
+	"github.com/golang/glog"
+	cadvisor "github.com/google/cadvisor/client"
+)
+
+// TODO: move this into a pkg/util
+func GetHostname(hostnameOverride string) string {
+	hostname := []byte(hostnameOverride)
+	if string(hostname) == "" {
+		// Note: We use exec here instead of os.Hostname() because we
+		// want the FQDN, and this is the easiest way to get it.
+		fqdn, err := exec.Command("hostname", "-f").Output()
+		if err != nil {
+			glog.Fatalf("Couldn't determine hostname: %v", err)
+		}
+		hostname = fqdn
+	}
+	return strings.TrimSpace(string(hostname))
+}
+
+// TODO: move this into a pkg/util
+func GetDockerEndpoint(dockerEndpoint string) string {
+	var endpoint string
+	if len(dockerEndpoint) > 0 {
+		endpoint = dockerEndpoint
+	} else if len(os.Getenv("DOCKER_HOST")) > 0 {
+		endpoint = os.Getenv("DOCKER_HOST")
+	} else {
+		endpoint = "unix:///var/run/docker.sock"
+	}
+	glog.Infof("Connecting to docker on %s", endpoint)
+
+	return endpoint
+}
+
+// TODO: move this into pkg/util
+func ConnectToDockerOrDie(dockerEndpoint string) *docker.Client {
+	client, err := docker.NewClient(GetDockerEndpoint(dockerEndpoint))
+	if err != nil {
+		glog.Fatal("Couldn't connect to docker.")
+	}
+	return client
+}
+
+// TODO: move this into the kubelet itself
+func GarbageCollectLoop(k *Kubelet) {
+	func() {
+		util.Forever(func() {
+			err := k.GarbageCollectContainers()
+			if err != nil {
+				glog.Errorf("Garbage collect failed: %v", err)
+			}
+		}, time.Minute*1)
+	}()
+}
+
+// TODO: move this into the kubelet itself
+func MonitorCAdvisor(k *Kubelet) {
+	defer util.HandleCrash()
+	// TODO: Monitor this connection, reconnect if needed?
+	glog.V(1).Infof("Trying to create cadvisor client.")
+	cadvisorClient, err := cadvisor.NewClient("http://127.0.0.1:4194")
+	if err != nil {
+		glog.Errorf("Error on creating cadvisor client: %v", err)
+		return
+	}
+	glog.V(1).Infof("Successfully created cadvisor client.")
+	k.SetCadvisorClient(cadvisorClient)
+}
+
+// TODO: move this into the kubelet itself
+func InitHealthChecking(k *Kubelet) {
+	// TODO: These should probably become more plugin-ish: register a factory func
+	// in each checker's init(), iterate those here.
+	health.AddHealthChecker(health.NewExecHealthChecker(k))
+	health.AddHealthChecker(health.NewHTTPHealthChecker(&http.Client{}))
+	health.AddHealthChecker(&health.TCPHealthChecker{})
+}
+
+// TODO: move this into a pkg/tools/etcd_tools
+func EtcdClientOrDie(etcdServerList util.StringList, etcdConfigFile string) *etcd.Client {
+	if len(etcdServerList) > 0 {
+		return etcd.NewClient(etcdServerList)
+	} else if etcdConfigFile != "" {
+		etcdClient, err := etcd.NewClientFromFile(etcdConfigFile)
+		if err != nil {
+			glog.Fatalf("Error with etcd config file: %v", err)
+		}
+		return etcdClient
+	}
+	return nil
+}
+
+// TODO: move this into pkg/util
+func SetupRootDirectoryOrDie(rootDirectory string) {
+	if rootDirectory == "" {
+		glog.Fatal("Invalid root directory path.")
+	}
+	rootDirectory = path.Clean(rootDirectory)
+	if err := os.MkdirAll(rootDirectory, 0750); err != nil {
+		glog.Fatalf("Error creating root directory: %v", err)
+	}
+}
+
+// TODO: move this into pkg/capabilities
+func SetupCapabilities(allowPrivileged bool) {
+	capabilities.Initialize(capabilities.Capabilities{
+		AllowPrivileged: allowPrivileged,
+	})
+}
+
+// TODO: Split this up?
+func SetupLogging() {
+	etcd.SetLogger(util.NewLogger("etcd "))
+	// Log the events locally too.
+	record.StartLogging(glog.Infof)
+}
+
+// TODO: move this into pkg/client
+func getApiserverClient(authPath string, apiServerList util.StringList) (*client.Client, error) {
+	authInfo, err := clientauth.LoadFromFile(authPath)
+	if err != nil {
+		return nil, err
+	}
+	clientConfig, err := authInfo.MergeWithConfig(client.Config{})
+	if err != nil {
+		return nil, err
+	}
+	// TODO: adapt Kube client to support LB over several servers
+	if len(apiServerList) > 1 {
+		glog.Infof("Mulitple api servers specified.  Picking first one")
+	}
+	clientConfig.Host = apiServerList[0]
+	if c, err := client.New(&clientConfig); err != nil {
+		return nil, err
+	} else {
+		return c, nil
+	}
+}
+
+func SetupEventSending(authPath string, apiServerList util.StringList) {
+	// Make an API client if possible.
+	if len(apiServerList) < 1 {
+		glog.Info("No api servers specified.")
+	} else {
+		if apiClient, err := getApiserverClient(authPath, apiServerList); err != nil {
+			glog.Errorf("Unable to make apiserver client: %v", err)
+		} else {
+			// Send events to APIserver if there is a client.
+			glog.Infof("Sending events to APIserver.")
+			record.StartRecording(apiClient.Events(""), "kubelet")
+		}
+	}
+}

pkg/standalone/standalone.go

@@ -31,6 +31,7 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/controller"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/config"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/dockertools"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/master"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/resources"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/service"
@@ -39,12 +40,9 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/plugin/pkg/scheduler"
 	"github.com/GoogleCloudPlatform/kubernetes/plugin/pkg/scheduler/factory"
 
-	docker "github.com/fsouza/go-dockerclient"
 	"github.com/golang/glog"
 )
 
-const testRootDir = "/tmp/kubelet"
-
 type delegateHandler struct {
 	delegate http.Handler
 }
@@ -141,20 +139,131 @@ func RunControllerManager(machineList []string, cl *client.Client, nodeMilliCPU,
 	controllerManager.Run(10 * time.Second)
 }
 
-// RunKubelet starts a Kubelet talking to dockerEndpoint
+// SimpleRunKubelet is a simple way to start a Kubelet talking to dockerEndpoint, using an etcdClient.
-func RunKubelet(etcdClient tools.EtcdClient, hostname, dockerEndpoint string) {
+// Under the hood it calls RunKubelet (below)
-	dockerClient, err := docker.NewClient(GetDockerEndpoint(dockerEndpoint))
+func SimpleRunKubelet(etcdClient tools.EtcdClient, dockerClient dockertools.DockerInterface, hostname, rootDir, manifestURL, address string, port uint) {
-	if err != nil {
+	kcfg := KubeletConfig{
-		glog.Fatal("Couldn't connect to docker.")
+		EtcdClient:            etcdClient,
+		DockerClient:          dockerClient,
+		HostnameOverride:      hostname,
+		RootDirectory:         rootDir,
+		ManifestURL:           manifestURL,
+		NetworkContainerImage: kubelet.NetworkContainerImage,
+		Port:                    port,
+		Address:                 util.IP(net.ParseIP(address)),
+		EnableServer:            true,
+		EnableDebuggingHandlers: true,
+	}
+	RunKubelet(&kcfg)
+}
+
+// RunKubelet is responsible for setting up and running a kubelet.  It is used in three different applications:
+//   1 Integration tests
+//   2 Kubelet binary
+//   3 Standalone 'kubernetes' binary
+// Eventually, #2 will be replaced with instances of #3
+func RunKubelet(kcfg *KubeletConfig) {
+	kubelet.SetupEventSending(kcfg.AuthPath, kcfg.ApiServerList)
+	kubelet.SetupLogging()
+	kubelet.SetupCapabilities(kcfg.AllowPrivileged)
+
+	kcfg.Hostname = kubelet.GetHostname(kcfg.HostnameOverride)
+	if len(kcfg.RootDirectory) > 0 {
+		kubelet.SetupRootDirectoryOrDie(kcfg.RootDirectory)
 	}
 
-	// Kubelet (localhost)
+	cfg := makePodSourceConfig(kcfg)
-	os.MkdirAll(testRootDir, 0750)
+	k := createAndInitKubelet(kcfg)
-	cfg1 := config.NewPodConfig(config.PodConfigNotificationSnapshotAndUpdates)
+	// process pods and exit.
-	config.NewSourceEtcd(config.EtcdKeyForHost(hostname), etcdClient, cfg1.Channel("etcd"))
+	if kcfg.Runonce {
-	myKubelet := kubelet.NewIntegrationTestKubelet(hostname, testRootDir, dockerClient)
+		if _, err := k.RunOnce(cfg.Updates()); err != nil {
-	go util.Forever(func() { myKubelet.Run(cfg1.Updates()) }, 0)
+			glog.Errorf("--runonce failed: %v", err)
-	go util.Forever(func() {
+		}
-		kubelet.ListenAndServeKubeletServer(myKubelet, cfg1.Channel("http"), net.ParseIP("127.0.0.1"), 10250, true)
+	} else {
-	}, 0)
+		startKubelet(k, cfg, kcfg)
+	}
+}
+
+func startKubelet(k *kubelet.Kubelet, cfg *config.PodConfig, kc *KubeletConfig) {
+	// start the kubelet
+	go util.Forever(func() { k.Run(cfg.Updates()) }, 0)
+
+	// start the kubelet server
+	if kc.EnableServer {
+		go util.Forever(func() {
+			kubelet.ListenAndServeKubeletServer(k, cfg.Channel("http"), net.IP(kc.Address), kc.Port, kc.EnableDebuggingHandlers)
+		}, 0)
+	}
+}
+
+func makePodSourceConfig(kc *KubeletConfig) *config.PodConfig {
+	// source of all configuration
+	cfg := config.NewPodConfig(config.PodConfigNotificationSnapshotAndUpdates)
+
+	// define file config source
+	if kc.ConfigFile != "" {
+		config.NewSourceFile(kc.ConfigFile, kc.FileCheckFrequency, cfg.Channel("file"))
+	}
+
+	// define url config source
+	if kc.ManifestURL != "" {
+		config.NewSourceURL(kc.ManifestURL, kc.HttpCheckFrequency, cfg.Channel("http"))
+	}
+
+	if kc.EtcdClient != nil {
+		glog.Infof("Watching for etcd configs at %v", kc.EtcdClient.GetCluster())
+		config.NewSourceEtcd(config.EtcdKeyForHost(kc.Hostname), kc.EtcdClient, cfg.Channel("etcd"))
+	}
+	return cfg
+}
+
+type KubeletConfig struct {
+	EtcdClient              tools.EtcdClient
+	DockerClient            dockertools.DockerInterface
+	Address                 util.IP
+	AuthPath                string
+	ApiServerList           util.StringList
+	AllowPrivileged         bool
+	HostnameOverride        string
+	RootDirectory           string
+	ConfigFile              string
+	ManifestURL             string
+	FileCheckFrequency      time.Duration
+	HttpCheckFrequency      time.Duration
+	Hostname                string
+	NetworkContainerImage   string
+	SyncFrequency           time.Duration
+	RegistryPullQPS         float64
+	RegistryBurst           int
+	MinimumGCAge            time.Duration
+	MaxContainerCount       int
+	EnableServer            bool
+	EnableDebuggingHandlers bool
+	Port                    uint
+	Runonce                 bool
+}
+
+func createAndInitKubelet(kc *KubeletConfig) *kubelet.Kubelet {
+	// TODO: block until all sources have delivered at least one update to the channel, or break the sync loop
+	// up into "per source" synchronizations
+
+	k := kubelet.NewMainKubelet(
+		kc.Hostname,
+		kc.DockerClient,
+		kc.EtcdClient,
+		kc.RootDirectory,
+		kc.NetworkContainerImage,
+		kc.SyncFrequency,
+		float32(kc.RegistryPullQPS),
+		kc.RegistryBurst,
+		kc.MinimumGCAge,
+		kc.MaxContainerCount)
+
+	k.BirthCry()
+
+	go kubelet.GarbageCollectLoop(k)
+	go kubelet.MonitorCAdvisor(k)
+	kubelet.InitHealthChecking(k)
+
+	return k
 }