NewMainKubelet validates Kubelet config parameters

Fixes issue kubernetes#3202.
* Validates SyncFrequency and minimum GC age and propagates error to RunKubelet
* Defaults for Kubelet config and minor cleanup
* cmd Kubelet MinimumGCAge to 1m instead of 0

cmd/kubelet/kubelet.go

@@ -57,7 +57,7 @@ var (
  registryBurst = flag.Int("registry_burst", 10, "Maximum size of a bursty pulls, temporarily allows pulls to burst to this number, while still not exceeding registry_qps. Only used if --registry_qps > 0")
  runonce = flag.Bool("runonce", false, "If true, exit after spawning pods from local manifests or remote urls. Exclusive with --etcd_servers and --enable-server")
  enableDebuggingHandlers = flag.Bool("enable_debugging_handlers", true, "Enables server endpoints for log collection and local running of containers and commands")
- minimumGCAge = flag.Duration("minimum_container_ttl_duration", 0, "Minimum age for a finished container before it is garbage collected. Examples: '300ms', '10s' or '2h45m'")
+ minimumGCAge = flag.Duration("minimum_container_ttl_duration", 1*time.Minute, "Minimum age for a finished container before it is garbage collected. Examples: '300ms', '10s' or '2h45m'")
  maxContainerCount = flag.Int("maximum_dead_containers_per_container", 5, "Maximum number of old instances of a container to retain per container. Each container takes up some disk space. Default: 5.")
  authPath = flag.String("auth_path", "", "Path to .kubernetes_auth file, specifying how to authenticate to API server.")
  cAdvisorPort = flag.Uint("cadvisor_port", 4194, "The port of the localhost cAdvisor endpoint")

pkg/kubelet/kubelet.go

@@ -61,29 +61,35 @@ type volumeMap map[string]volume.Interface
 
 // New creates a new Kubelet for use in main
 func NewMainKubelet(
- hn string,
- dc dockertools.DockerInterface,
- ec tools.EtcdClient,
- rd string,
- ni string,
- ri time.Duration,
+ hostname string,
+ dockerClient dockertools.DockerInterface,
+ etcdClient tools.EtcdClient,
+ rootDirectory string,
+ networkContainerImage string,
+ resyncInterval time.Duration,
  pullQPS float32,
  pullBurst int,
  minimumGCAge time.Duration,
  maxContainerCount int,
  sourcesReady SourcesReadyFn,
  clusterDomain string,
- clusterDNS net.IP) *Kubelet {
+ clusterDNS net.IP) (*Kubelet, error) {
+ if resyncInterval <= 0 {
+ return nil, fmt.Errorf("invalid sync frequency %d", resyncInterval)
+ }
+ if minimumGCAge <= 0 {
+ return nil, fmt.Errorf("invalid minimum GC age %d", minimumGCAge)
+ }
  return &Kubelet{
- hostname: hn,
- dockerClient: dc,
- etcdClient: ec,
- rootDirectory: rd,
- resyncInterval: ri,
- networkContainerImage: ni,
+ hostname: hostname,
+ dockerClient: dockerClient,
+ etcdClient: etcdClient,
+ rootDirectory: rootDirectory,
+ resyncInterval: resyncInterval,
+ networkContainerImage: networkContainerImage,
  podWorkers: newPodWorkers(),
  dockerIDToRef: map[dockertools.DockerID]*api.ObjectReference{},
- runner: dockertools.NewDockerContainerCommandRunner(dc),
+ runner: dockertools.NewDockerContainerCommandRunner(dockerClient),
  httpClient: &http.Client{},
  pullQPS: pullQPS,
  pullBurst: pullBurst,
@@ -92,7 +98,7 @@ func NewMainKubelet(
  sourcesReady: sourcesReady,
  clusterDomain: clusterDomain,
  clusterDNS: clusterDNS,
- }
+ }, nil
 }
 
 type httpGetter interface {
@@ -202,7 +208,7 @@ func (kl *Kubelet) purgeOldest(ids []string) error {
  if err != nil {
  return err
  }
- if !data.State.Running && (kl.minimumGCAge == 0 || time.Now().Sub(data.State.FinishedAt) > kl.minimumGCAge) {
+ if !data.State.Running && (time.Now().Sub(data.State.FinishedAt) > kl.minimumGCAge) {
  dockerData = append(dockerData, data)
  }
  }

pkg/standalone/standalone.go

@@ -142,6 +142,8 @@ func SimpleRunKubelet(etcdClient tools.EtcdClient, dockerClient dockertools.Dock
  EnableServer: true,
  EnableDebuggingHandlers: true,
  SyncFrequency: 3 * time.Second,
+ MinimumGCAge: 10 * time.Second,
+ MaxContainerCount: 5,
  }
  RunKubelet(&kcfg)
 }
@@ -162,7 +164,11 @@ func RunKubelet(kcfg *KubeletConfig) {
  }
 
  cfg := makePodSourceConfig(kcfg)
- k := createAndInitKubelet(kcfg, cfg)
+ k, err := createAndInitKubelet(kcfg, cfg)
+ if err != nil {
+ glog.Errorf("Failed to create kubelet: %s", err)
+ return
+ }
  // process pods and exit.
  if kcfg.Runonce {
  if _, err := k.RunOnce(cfg.Updates()); err != nil {
@@ -237,11 +243,11 @@ type KubeletConfig struct {
  Runonce bool
 }
 
-func createAndInitKubelet(kc *KubeletConfig, pc *config.PodConfig) *kubelet.Kubelet {
+func createAndInitKubelet(kc *KubeletConfig, pc *config.PodConfig) (*kubelet.Kubelet, error) {
  // 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(
+ k, err := kubelet.NewMainKubelet(
  kc.Hostname,
  kc.DockerClient,
  kc.EtcdClient,
@@ -256,11 +262,15 @@ func createAndInitKubelet(kc *KubeletConfig, pc *config.PodConfig) *kubelet.Kube
  kc.ClusterDomain,
  net.IP(kc.ClusterDNS))
 
+ if err != nil {
+ return nil, err
+ }
+
  k.BirthCry()
 
  go k.GarbageCollectLoop()
  go kubelet.MonitorCAdvisor(k, kc.CAdvisorPort)
  kubelet.InitHealthChecking(k)
 
- return k
+ return k, nil
 }