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k8s.io/kubernetes / pkg / kubelet

package kubelet

v1.18.5
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Published: Jun 26, 2020 | License: Apache-2.0 | Module: k8s.io/kubernetes

Overview

Package kubelet is the package that contains the libraries that drive the Kubelet binary. The kubelet is responsible for node level pod management. It runs on each worker in the cluster.

Index

Constants

const (

	// ContainerLogsDir is the location of container logs.
	ContainerLogsDir = "/var/log/containers"

	// MaxContainerBackOff is the max backoff period, exported for the e2e test
	MaxContainerBackOff = 300 * time.Second

	// ContainerGCPeriod is the period for performing container garbage collection.
	ContainerGCPeriod = time.Minute
	// ImageGCPeriod is the period for performing image garbage collection.
	ImageGCPeriod = 5 * time.Minute
)
const (
	// KubeMarkMasqChain is the mark-for-masquerade chain
	// TODO: clean up this logic in kube-proxy
	KubeMarkMasqChain utiliptables.Chain = "KUBE-MARK-MASQ"

	// KubeMarkDropChain is the mark-for-drop chain
	KubeMarkDropChain utiliptables.Chain = "KUBE-MARK-DROP"

	// KubePostroutingChain is kubernetes postrouting rules
	KubePostroutingChain utiliptables.Chain = "KUBE-POSTROUTING"

	// KubeFirewallChain is kubernetes firewall rules
	KubeFirewallChain utiliptables.Chain = "KUBE-FIREWALL"
)
const (
	// NetworkNotReadyErrorMsg is used to describe the error that network is not ready
	NetworkNotReadyErrorMsg = "network is not ready"
)

Variables

var (
	// ErrNetworkUnknown indicates the network state is unknown
	ErrNetworkUnknown = errors.New("network state unknown")
)

func NewInitializedVolumePluginMgr

func NewInitializedVolumePluginMgr(
	kubelet *Kubelet,
	secretManager secret.Manager,
	configMapManager configmap.Manager,
	tokenManager *token.Manager,
	plugins []volume.VolumePlugin,
	prober volume.DynamicPluginProber) (*volume.VolumePluginMgr, error)

NewInitializedVolumePluginMgr returns a new instance of volume.VolumePluginMgr initialized with kubelets implementation of the volume.VolumeHost interface.

kubelet - used by VolumeHost methods to expose kubelet specific parameters plugins - used to initialize volumePluginMgr

func PreInitRuntimeService

func PreInitRuntimeService(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
	kubeDeps *Dependencies,
	crOptions *config.ContainerRuntimeOptions,
	containerRuntime string,
	runtimeCgroups string,
	remoteRuntimeEndpoint string,
	remoteImageEndpoint string,
	nonMasqueradeCIDR string) error

PreInitRuntimeService will init runtime service before RunKubelet.

type Bootstrap

type Bootstrap interface {
	GetConfiguration() kubeletconfiginternal.KubeletConfiguration
	BirthCry()
	StartGarbageCollection()
	ListenAndServe(address net.IP, port uint, tlsOptions *server.TLSOptions, auth server.AuthInterface, enableCAdvisorJSONEndpoints, enableDebuggingHandlers, enableContentionProfiling bool)
	ListenAndServeReadOnly(address net.IP, port uint, enableCAdvisorJSONEndpoints bool)
	ListenAndServePodResources()
	Run(<-chan kubetypes.PodUpdate)
	RunOnce(<-chan kubetypes.PodUpdate) ([]RunPodResult, error)
}

Bootstrap is a bootstrapping interface for kubelet, targets the initialization protocol

type Builder

type Builder func(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
	kubeDeps *Dependencies,
	crOptions *config.ContainerRuntimeOptions,
	containerRuntime string,
	runtimeCgroups string,
	hostnameOverride string,
	nodeIP string,
	providerID string,
	cloudProvider string,
	certDirectory string,
	rootDirectory string,
	registerNode bool,
	registerWithTaints []api.Taint,
	allowedUnsafeSysctls []string,
	remoteRuntimeEndpoint string,
	remoteImageEndpoint string,
	experimentalMounterPath string,
	experimentalKernelMemcgNotification bool,
	experimentalCheckNodeCapabilitiesBeforeMount bool,
	experimentalNodeAllocatableIgnoreEvictionThreshold bool,
	minimumGCAge metav1.Duration,
	maxPerPodContainerCount int32,
	maxContainerCount int32,
	masterServiceNamespace string,
	registerSchedulable bool,
	nonMasqueradeCIDR string,
	keepTerminatedPodVolumes bool,
	nodeLabels map[string]string,
	seccompProfileRoot string,
	bootstrapCheckpointPath string,
	nodeStatusMaxImages int32) (Bootstrap, error)

Builder creates and initializes a Kubelet instance

type Dependencies

type Dependencies struct {
	Options []Option

	// Injected Dependencies
	Auth                    server.AuthInterface
	CAdvisorInterface       cadvisor.Interface
	Cloud                   cloudprovider.Interface
	ContainerManager        cm.ContainerManager
	DockerClientConfig      *dockershim.ClientConfig
	EventClient             v1core.EventsGetter
	HeartbeatClient         clientset.Interface
	OnHeartbeatFailure      func()
	KubeClient              clientset.Interface
	Mounter                 mount.Interface
	HostUtil                hostutil.HostUtils
	OOMAdjuster             *oom.OOMAdjuster
	OSInterface             kubecontainer.OSInterface
	PodConfig               *config.PodConfig
	Recorder                record.EventRecorder
	Subpather               subpath.Interface
	VolumePlugins           []volume.VolumePlugin
	DynamicPluginProber     volume.DynamicPluginProber
	TLSOptions              *server.TLSOptions
	KubeletConfigController *kubeletconfig.Controller
	RemoteRuntimeService    internalapi.RuntimeService
	RemoteImageService      internalapi.ImageManagerService
	// contains filtered or unexported fields
}

Dependencies is a bin for things we might consider "injected dependencies" -- objects constructed at runtime that are necessary for running the Kubelet. This is a temporary solution for grouping these objects while we figure out a more comprehensive dependency injection story for the Kubelet.

type KillPodOptions

type KillPodOptions struct {
	// PodStatusFunc is the function to invoke to set pod status in response to a kill request.
	PodStatusFunc PodStatusFunc
	// PodTerminationGracePeriodSecondsOverride is optional override to use if a pod is being killed as part of kill operation.
	PodTerminationGracePeriodSecondsOverride *int64
}

KillPodOptions are options when performing a pod update whose update type is kill.

type Kubelet

type Kubelet struct {

	// the list of handlers to call during pod sync loop.
	lifecycle.PodSyncLoopHandlers

	// the list of handlers to call during pod sync.
	lifecycle.PodSyncHandlers

	// StatsProvider provides the node and the container stats.
	*stats.StatsProvider
	// contains filtered or unexported fields
}

Kubelet is the main kubelet implementation.

func NewMainKubelet

func NewMainKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
	kubeDeps *Dependencies,
	crOptions *config.ContainerRuntimeOptions,
	containerRuntime string,
	hostnameOverride string,
	nodeIP string,
	providerID string,
	cloudProvider string,
	certDirectory string,
	rootDirectory string,
	registerNode bool,
	registerWithTaints []api.Taint,
	allowedUnsafeSysctls []string,
	experimentalMounterPath string,
	experimentalKernelMemcgNotification bool,
	experimentalCheckNodeCapabilitiesBeforeMount bool,
	experimentalNodeAllocatableIgnoreEvictionThreshold bool,
	minimumGCAge metav1.Duration,
	maxPerPodContainerCount int32,
	maxContainerCount int32,
	masterServiceNamespace string,
	registerSchedulable bool,
	keepTerminatedPodVolumes bool,
	nodeLabels map[string]string,
	seccompProfileRoot string,
	bootstrapCheckpointPath string,
	nodeStatusMaxImages int32) (*Kubelet, error)

NewMainKubelet instantiates a new Kubelet object along with all the required internal modules. No initialization of Kubelet and its modules should happen here.

func (*Kubelet) BirthCry

func (kl *Kubelet) BirthCry()

BirthCry sends an event that the kubelet has started up.

func (*Kubelet) GeneratePodHostNameAndDomain

func (kl *Kubelet) GeneratePodHostNameAndDomain(pod *v1.Pod) (string, string, error)

GeneratePodHostNameAndDomain creates a hostname and domain name for a pod, given that pod's spec and annotations or returns an error.

func (*Kubelet) GenerateRunContainerOptions

func (kl *Kubelet) GenerateRunContainerOptions(pod *v1.Pod, container *v1.Container, podIP string, podIPs []string) (*kubecontainer.RunContainerOptions, func(), error)

GenerateRunContainerOptions generates the RunContainerOptions, which can be used by the container runtime to set parameters for launching a container.

func (*Kubelet) GetActivePods

func (kl *Kubelet) GetActivePods() []*v1.Pod

GetActivePods returns non-terminal pods

func (*Kubelet) GetAttach

func (kl *Kubelet) GetAttach(podFullName string, podUID types.UID, containerName string, streamOpts remotecommandserver.Options) (*url.URL, error)

GetAttach gets the URL the attach will be served from, or nil if the Kubelet will serve it.

func (*Kubelet) GetCachedMachineInfo

func (kl *Kubelet) GetCachedMachineInfo() (*cadvisorapiv1.MachineInfo, error)

GetCachedMachineInfo assumes that the machine info can't change without a reboot

func (*Kubelet) GetConfiguration

func (kl *Kubelet) GetConfiguration() kubeletconfiginternal.KubeletConfiguration

GetConfiguration returns the KubeletConfiguration used to configure the kubelet.

func (*Kubelet) GetExec

func (kl *Kubelet) GetExec(podFullName string, podUID types.UID, containerName string, cmd []string, streamOpts remotecommandserver.Options) (*url.URL, error)

GetExec gets the URL the exec will be served from, or nil if the Kubelet will serve it.

func (*Kubelet) GetExtraSupplementalGroupsForPod

func (kl *Kubelet) GetExtraSupplementalGroupsForPod(pod *v1.Pod) []int64

GetExtraSupplementalGroupsForPod returns a list of the extra supplemental groups for the Pod. These extra supplemental groups come from annotations on persistent volumes that the pod depends on.

func (*Kubelet) GetHostIP

func (kl *Kubelet) GetHostIP() (net.IP, error)

GetHostIP returns host IP or nil in case of error.

func (*Kubelet) GetHostname

func (kl *Kubelet) GetHostname() string

GetHostname Returns the hostname as the kubelet sees it.

func (*Kubelet) GetKubeletContainerLogs

func (kl *Kubelet) GetKubeletContainerLogs(ctx context.Context, podFullName, containerName string, logOptions *v1.PodLogOptions, stdout, stderr io.Writer) error

GetKubeletContainerLogs returns logs from the container TODO: this method is returning logs of random container attempts, when it should be returning the most recent attempt or all of them.

func (*Kubelet) GetNode

func (kl *Kubelet) GetNode() (*v1.Node, error)

GetNode returns the node info for the configured node name of this Kubelet.

func (*Kubelet) GetNodeConfig

func (kl *Kubelet) GetNodeConfig() cm.NodeConfig

GetNodeConfig returns the container manager node config.

func (*Kubelet) GetPodByCgroupfs

func (kl *Kubelet) GetPodByCgroupfs(cgroupfs string) (*v1.Pod, bool)

GetPodByCgroupfs provides the pod that maps to the specified cgroup, as well as whether the pod was found.

func (*Kubelet) GetPodByFullName

func (kl *Kubelet) GetPodByFullName(podFullName string) (*v1.Pod, bool)

GetPodByFullName gets the pod with the given 'full' name, which incorporates the namespace as well as whether the pod was found.

func (*Kubelet) GetPodByName

func (kl *Kubelet) GetPodByName(namespace, name string) (*v1.Pod, bool)

GetPodByName provides the first pod that matches namespace and name, as well as whether the pod was found.

func (*Kubelet) GetPodCgroupParent

func (kl *Kubelet) GetPodCgroupParent(pod *v1.Pod) string

GetPodCgroupParent gets pod cgroup parent from container manager.

func (*Kubelet) GetPodCgroupRoot

func (kl *Kubelet) GetPodCgroupRoot() string

GetPodCgroupRoot returns the listeral cgroupfs value for the cgroup containing all pods

func (*Kubelet) GetPodDNS

func (kl *Kubelet) GetPodDNS(pod *v1.Pod) (*runtimeapi.DNSConfig, error)

GetPodDNS returns DNS settings for the pod. This function is defined in kubecontainer.RuntimeHelper interface so we have to implement it.

func (*Kubelet) GetPodDir

func (kl *Kubelet) GetPodDir(podUID types.UID) string

GetPodDir returns the full path to the per-pod data directory for the specified pod. This directory may not exist if the pod does not exist.

func (*Kubelet) GetPods

func (kl *Kubelet) GetPods() []*v1.Pod

GetPods returns all pods bound to the kubelet and their spec, and the mirror pods.

func (*Kubelet) GetPortForward

func (kl *Kubelet) GetPortForward(podName, podNamespace string, podUID types.UID, portForwardOpts portforward.V4Options) (*url.URL, error)

GetPortForward gets the URL the port-forward will be served from, or nil if the Kubelet will serve it.

func (*Kubelet) GetRunningPods

func (kl *Kubelet) GetRunningPods() ([]*v1.Pod, error)

GetRunningPods returns all pods running on kubelet from looking at the container runtime cache. This function converts kubecontainer.Pod to v1.Pod, so only the fields that exist in both kubecontainer.Pod and v1.Pod are considered meaningful.

func (*Kubelet) GetVersionInfo

func (kl *Kubelet) GetVersionInfo() (*cadvisorapiv1.VersionInfo, error)

GetVersionInfo returns information about the version of cAdvisor in use.

func (*Kubelet) HandlePodAdditions

func (kl *Kubelet) HandlePodAdditions(pods []*v1.Pod)

HandlePodAdditions is the callback in SyncHandler for pods being added from a config source.

func (*Kubelet) HandlePodCleanups

func (kl *Kubelet) HandlePodCleanups() error

HandlePodCleanups performs a series of cleanup work, including terminating pod workers, killing unwanted pods, and removing orphaned volumes/pod directories. NOTE: This function is executed by the main sync loop, so it should not contain any blocking calls.

func (*Kubelet) HandlePodReconcile

func (kl *Kubelet) HandlePodReconcile(pods []*v1.Pod)

HandlePodReconcile is the callback in the SyncHandler interface for pods that should be reconciled.

func (*Kubelet) HandlePodRemoves

func (kl *Kubelet) HandlePodRemoves(pods []*v1.Pod)

HandlePodRemoves is the callback in the SyncHandler interface for pods being removed from a config source.

func (*Kubelet) HandlePodSyncs

func (kl *Kubelet) HandlePodSyncs(pods []*v1.Pod)

HandlePodSyncs is the callback in the syncHandler interface for pods that should be dispatched to pod workers for sync.

func (*Kubelet) HandlePodUpdates

func (kl *Kubelet) HandlePodUpdates(pods []*v1.Pod)

HandlePodUpdates is the callback in the SyncHandler interface for pods being updated from a config source.

func (*Kubelet) IsPodDeleted

func (kl *Kubelet) IsPodDeleted(uid types.UID) bool

IsPodDeleted returns true if the pod is deleted. For the pod to be deleted, either: 1. The pod object is deleted 2. The pod's status is evicted 3. The pod's deletion timestamp is set, and containers are not running

func (*Kubelet) IsPodTerminated

func (kl *Kubelet) IsPodTerminated(uid types.UID) bool

IsPodTerminated returns true if the pod with the provided UID is in a terminal phase ("Failed", "Succeeded") or has been deleted and has no running containers. This corresponds to when a pod must accept changes to its pod spec (e.g. terminating containers allow grace period to be shortened)

func (*Kubelet) LatestLoopEntryTime

func (kl *Kubelet) LatestLoopEntryTime() time.Time

LatestLoopEntryTime returns the last time in the sync loop monitor.

func (*Kubelet) ListVolumesForPod

func (kl *Kubelet) ListVolumesForPod(podUID types.UID) (map[string]volume.Volume, bool)

ListVolumesForPod returns a map of the mounted volumes for the given pod. The key in the map is the OuterVolumeSpecName (i.e. pod.Spec.Volumes[x].Name)

func (*Kubelet) ListenAndServe

func (kl *Kubelet) ListenAndServe(address net.IP, port uint, tlsOptions *server.TLSOptions, auth server.AuthInterface, enableCAdvisorJSONEndpoints, enableDebuggingHandlers, enableContentionProfiling bool)

ListenAndServe runs the kubelet HTTP server.

func (*Kubelet) ListenAndServePodResources

func (kl *Kubelet) ListenAndServePodResources()

ListenAndServePodResources runs the kubelet podresources grpc service

func (*Kubelet) ListenAndServeReadOnly

func (kl *Kubelet) ListenAndServeReadOnly(address net.IP, port uint, enableCAdvisorJSONEndpoints bool)

ListenAndServeReadOnly runs the kubelet HTTP server in read-only mode.

func (*Kubelet) PodResourcesAreReclaimed

func (kl *Kubelet) PodResourcesAreReclaimed(pod *v1.Pod, status v1.PodStatus) bool

PodResourcesAreReclaimed returns true if all required node-level resources that a pod was consuming have been reclaimed by the kubelet. Reclaiming resources is a prerequisite to deleting a pod from the API server.

func (*Kubelet) ResyncInterval

func (kl *Kubelet) ResyncInterval() time.Duration

ResyncInterval returns the interval used for periodic syncs.

func (*Kubelet) Run

func (kl *Kubelet) Run(updates <-chan kubetypes.PodUpdate)

Run starts the kubelet reacting to config updates

func (*Kubelet) RunInContainer

func (kl *Kubelet) RunInContainer(podFullName string, podUID types.UID, containerName string, cmd []string) ([]byte, error)

RunInContainer runs a command in a container, returns the combined stdout, stderr as an array of bytes

func (*Kubelet) RunOnce

func (kl *Kubelet) RunOnce(updates <-chan kubetypes.PodUpdate) ([]RunPodResult, error)

RunOnce polls from one configuration update and run the associated pods.

func (*Kubelet) ServeLogs

func (kl *Kubelet) ServeLogs(w http.ResponseWriter, req *http.Request)

ServeLogs returns logs of current machine.

func (*Kubelet) StartGarbageCollection

func (kl *Kubelet) StartGarbageCollection()

StartGarbageCollection starts garbage collection threads.

type OnCompleteFunc

type OnCompleteFunc func(err error)

OnCompleteFunc is a function that is invoked when an operation completes. If err is non-nil, the operation did not complete successfully.

type Option

type Option func(*Kubelet)

Option is a functional option type for Kubelet

type PodStatusFunc

type PodStatusFunc func(pod *v1.Pod, podStatus *kubecontainer.PodStatus) v1.PodStatus

PodStatusFunc is a function that is invoked to generate a pod status.

type PodWorkers

type PodWorkers interface {
	UpdatePod(options *UpdatePodOptions)
	ForgetNonExistingPodWorkers(desiredPods map[types.UID]sets.Empty)
	ForgetWorker(uid types.UID)
}

PodWorkers is an abstract interface for testability.

type ReasonCache

type ReasonCache struct {
	// contains filtered or unexported fields
}

ReasonCache stores the failure reason of the latest container start in a string, keyed by <pod_UID>_<container_name>. The goal is to propagate this reason to the container status. This endeavor is "best-effort" for two reasons:

1. The cache is not persisted.
2. We use an LRU cache to avoid extra garbage collection work. This
   means that some entries may be recycled before a pod has been
   deleted.

TODO(random-liu): Use more reliable cache which could collect garbage of failed pod. TODO(random-liu): Move reason cache to somewhere better.

func NewReasonCache

func NewReasonCache() *ReasonCache

NewReasonCache creates an instance of 'ReasonCache'.

func (*ReasonCache) Get

func (c *ReasonCache) Get(uid types.UID, name string) (*ReasonItem, bool)

Get gets error reason from the cache. The return values are error reason, error message and whether an error reason is found in the cache. If no error reason is found, empty string will be returned for error reason and error message.

func (*ReasonCache) Remove

func (c *ReasonCache) Remove(uid types.UID, name string)

Remove removes error reason from the cache

func (*ReasonCache) Update

func (c *ReasonCache) Update(uid types.UID, result kubecontainer.PodSyncResult)

Update updates the reason cache with the SyncPodResult. Only SyncResult with StartContainer action will change the cache.

type ReasonItem

type ReasonItem struct {
	Err     error
	Message string
}

ReasonItem is the cached item in ReasonCache

type RunPodResult

type RunPodResult struct {
	Pod *v1.Pod
	Err error
}

RunPodResult defines the running results of a Pod.

type SyncHandler

type SyncHandler interface {
	HandlePodAdditions(pods []*v1.Pod)
	HandlePodUpdates(pods []*v1.Pod)
	HandlePodRemoves(pods []*v1.Pod)
	HandlePodReconcile(pods []*v1.Pod)
	HandlePodSyncs(pods []*v1.Pod)
	HandlePodCleanups() error
}

SyncHandler is an interface implemented by Kubelet, for testability

type UpdatePodOptions

type UpdatePodOptions struct {
	// pod to update
	Pod *v1.Pod
	// the mirror pod for the pod to update, if it is a static pod
	MirrorPod *v1.Pod
	// the type of update (create, update, sync, kill)
	UpdateType kubetypes.SyncPodType
	// optional callback function when operation completes
	// this callback is not guaranteed to be completed since a pod worker may
	// drop update requests if it was fulfilling a previous request.  this is
	// only guaranteed to be invoked in response to a kill pod request which is
	// always delivered.
	OnCompleteFunc OnCompleteFunc
	// if update type is kill, use the specified options to kill the pod.
	KillPodOptions *KillPodOptions
}

UpdatePodOptions is an options struct to pass to a UpdatePod operation.

Documentation was rendered with GOOS=linux and GOARCH=amd64.

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