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Kubernetes Node Controller怎么启动

发表于：2025-12-01 作者：千家信息网编辑

千家信息网最后更新 2025年12月01日，本篇内容介绍了"Kubernetes Node Controller怎么启动"的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔

千家信息网最后更新 2025年12月01日Kubernetes Node Controller怎么启动

本篇内容介绍了"Kubernetes Node Controller怎么启动"的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！

Node Controller的启动

if ctx.IsControllerEnabled(nodeControllerName) {    // 解析得到Cluster CIDR， # clusterCIDR is CIDR Range for Pods in cluster.        _, clusterCIDR, err := net.ParseCIDR(s.ClusterCIDR)                // 解析得到Service CIDR，# serviceCIDR is CIDR Range for Services in cluster.        _, serviceCIDR, err := net.ParseCIDR(s.ServiceCIDR)                // 创建NodeController实例        nodeController, err := nodecontroller.NewNodeController(                sharedInformers.Core().V1().Pods(),                sharedInformers.Core().V1().Nodes(),                sharedInformers.Extensions().V1beta1().DaemonSets(),                cloud,                clientBuilder.ClientOrDie("node-controller"),                s.PodEvictionTimeout.Duration,                s.NodeEvictionRate,                s.SecondaryNodeEvictionRate,                s.LargeClusterSizeThreshold,                s.UnhealthyZoneThreshold,                s.NodeMonitorGracePeriod.Duration,                s.NodeStartupGracePeriod.Duration,                s.NodeMonitorPeriod.Duration,                clusterCIDR,                serviceCIDR,                int(s.NodeCIDRMaskSize),                s.AllocateNodeCIDRs,                s.EnableTaintManager,                utilfeature.DefaultFeatureGate.Enabled(features.TaintBasedEvictions),        )            // 执行Run方法启动该Controller        nodeController.Run()                // sleep一个随机时间，该时间大小为 "ControllerStartInterval + rand.Float64()*1.0*float64(ControllerStartInterval))"，其中ControllerStartInterval可以通过配置kube-controller-manager的"--controller-start-interval"参数指定。        time.Sleep(wait.Jitter(s.ControllerStartInterval.Duration, ControllerStartJitter))}

因此，很清晰地，关键就在以下两步：

nodeController, err := nodecontroller.NewNodeController创建NodeController实例。
nodeController.Run()执行Run方法启动该Controller。

NodeController的定义

在分析NodeController的原理之前，我们有必要先看看NodeController是如何定义的，其完整的定义如下：

type NodeController struct { allocateNodeCIDRs bool cloud cloudprovider.Interface clusterCIDR *net.IPNet serviceCIDR *net.IPNet knownNodeSet map[string]*v1.Node kubeClient clientset.Interface // Method for easy mocking in unittest. lookupIP func(host string) ([]net.IP, error) // Value used if sync_nodes_status=False. NodeController will not proactively // sync node status in this case, but will monitor node status updated from kubelet. If // it doesn't receive update for this amount of time, it will start posting "NodeReady== // ConditionUnknown". The amount of time before which NodeController start evicting pods // is controlled via flag 'pod-eviction-timeout'. // Note: be cautious when changing the constant, it must work with nodeStatusUpdateFrequency // in kubelet. There are several constraints: // 1. nodeMonitorGracePeriod must be N times more than nodeStatusUpdateFrequency, where // N means number of retries allowed for kubelet to post node status. It is pointless // to make nodeMonitorGracePeriod be less than nodeStatusUpdateFrequency, since there // will only be fresh values from Kubelet at an interval of nodeStatusUpdateFrequency. // The constant must be less than podEvictionTimeout. // 2. nodeMonitorGracePeriod can't be too large for user experience - larger value takes // longer for user to see up-to-date node status. nodeMonitorGracePeriod time.Duration // Value controlling NodeController monitoring period, i.e. how often does NodeController // check node status posted from kubelet. This value should be lower than nodeMonitorGracePeriod. // TODO: Change node status monitor to watch based. nodeMonitorPeriod time.Duration // Value used if sync_nodes_status=False, only for node startup. When node // is just created, e.g. cluster bootstrap or node creation, we give a longer grace period. nodeStartupGracePeriod time.Duration // per Node map storing last observed Status together with a local time when it was observed. // This timestamp is to be used instead of LastProbeTime stored in Condition. We do this // to aviod the problem with time skew across the cluster. nodeStatusMap map[string]nodeStatusData now func() metav1.Time // Lock to access evictor workers evictorLock sync.Mutex // workers that evicts pods from unresponsive nodes. zonePodEvictor map[string]*RateLimitedTimedQueue // workers that are responsible for tainting nodes. zoneNotReadyOrUnreachableTainer map[string]*RateLimitedTimedQueue podEvictionTimeout time.Duration // The maximum duration before a pod evicted from a node can be forcefully terminated. maximumGracePeriod time.Duration recorder record.EventRecorder nodeLister corelisters.NodeLister nodeInformerSynced cache.InformerSynced daemonSetStore extensionslisters.DaemonSetLister daemonSetInformerSynced cache.InformerSynced podInformerSynced cache.InformerSynced // allocate/recycle CIDRs for node if allocateNodeCIDRs == true cidrAllocator CIDRAllocator // manages taints taintManager *NoExecuteTaintManager forcefullyDeletePod func(*v1.Pod) error nodeExistsInCloudProvider func(types.NodeName) (bool, error) computeZoneStateFunc func(nodeConditions []*v1.NodeCondition) (int, zoneState) enterPartialDisruptionFunc func(nodeNum int) float32 enterFullDisruptionFunc func(nodeNum int) float32 zoneStates map[string]zoneState evictionLimiterQPS float32 secondaryEvictionLimiterQPS float32 largeClusterThreshold int32 unhealthyZoneThreshold float32 // if set to true NodeController will start TaintManager that will evict Pods from // tainted nodes, if they're not tolerated. runTaintManager bool // if set to true NodeController will taint Nodes with 'TaintNodeNotReady' and 'TaintNodeUnreachable' // taints instead of evicting Pods itself. useTaintBasedEvictions bool}

NodeController的行为配置

整个NodeController结构体非常复杂，包含30+项，我们将重点关注：

clusterCIDR - 通过--cluster-cidr 来设置，表示CIDR Range for Pods in cluster。
serivceCIDR - 通过--service-cluster-ip-range来设置，表示CIDR Range for Services in cluster。
knownNodeSet - 用来记录NodeController observed节点的集合。
nodeMonitorGracePeriod - 通过--node-monitor-grace-period来设置，默认为40s，表示在标记某个Node为unhealthy前，允许40s内该Node unresponsive。
nodeMonitorPeriod - 通过--node-monitor-period 来设置，默认为5s，表示在NodeController中同步NodeStatus的周期。
nodeStatusMap - 用来记录每个Node最近一次观察到的Status。
zonePodEvictor - workers that evicts pods from unresponsive nodes.
zoneNotReadyOrUnreachableTainer - workers that are responsible for tainting nodes.
podEvictionTimeout - 通过--pod-eviction-timeout设置，默认为5min，表示在强制删除Pod时，允许的最大的Pod eviction时间。
maximumGracePeriod - The maximum duration before a pod evicted from a node can be forcefully terminated. 不可配置，代码中写死为5min。
nodeLister - 用来获取Node数据的Interface。
daemonSetStore - 用来获取 daemonSet数据的Interface。在通过Eviction方式删除Pods时，会跳过该Node上所有的daemonSet对应的Pods。
taintManager - 它是一个NoExecuteTaintManager对象，当runTaintManager(默认true)为true时:

PodInformer和NodeInformer将监听到PodAdd,PodDelete,PodUpdate和NodeAdd,NodeDelete,NodeUpdate事件后，
触发TraintManager执行对应的NoExecuteTaintManager.PodUpdated和NoExecuteTaintManager.NodeUpdated方法，
将事件加入到对应的queue(podUpdateQueue and nodeUpdateQueue)，TaintController会从这些queue中消费这些消息，
TaintController分别调用handlePodUpdate和handleNodeUpdate处理。
具体的TaintController的处理逻辑，后续再单独分析。

forcefullyDeletePod - 该方法用来NodeController调用apiserver接口强制删除该Pod。用来删除那些被调度到kubelet version 小于v1.1.0 Node上的Pod，因为kubelet v1.1.0之前的版本不支持graceful termination。
computeZoneStateFunc - 该方法返回Zone中NotReadyNodes数量以及该Zone的state。

如果没有一个Ready Node，则该node state为FullDisruption；
如果unhealthy Nodes所占的比例大于等于unhealthyZoneThreshold,则该node state为PartialDisruption;
否则该node state就是Narmal。

enterPartialDisruptionFunc - 该方法用当前node num对比largeClusterThreshold ：

如果nodeNum > largeClusterThreshold则返回secondaryEvictionLimiterQPS（默认为0.01）；
否则返回0，表示停止evict操作。

enterFullDisruptionFunc - 用来获取evictionLimiterQPS（默认为0.1）的方法，关于evictionLimiterQPS 的理解见下。
zoneStates - 表示各个zone的状态，状态值可以为

Initial;
Normal;
FullDisruption;
PartialDisruption;

evictionLimiterQPS - 通过--node-eviction-rate设置，默认为0.1，表示当某个Zone status为healthy时，每秒应该剔除的Nodes数量，即每10s剔除1个Node。
secondaryEvictionLimiterQPS - 通过--secondary-node-eviction-rate设置，默认为0.01，表示当某个Zone status为unhealthy时，每秒应该剔除的Nodes数量，即每100s剔除1个Node。
largeClusterThreshold - 通过--large-cluster-size-threshold设置，默认为50，表示当健康nodes组成的集群规模小于等于50时，secondary-node-eviction-rate将被设置为0。
unhealthyZoneThreshold - 通过--unhealthy-zone-threshold设置，默认为0.55，表示当某个Zone中unhealthy Nodes（最少为3）所占的比例达到0.55时，就认为该Zone的状态为unhealthy。
runTaintManager - 在--enable-taint-manager中指定，默认为true。如果为true，则表示NodeController将会启动TaintManager，由TaintManager负责将不能容忍该Taint的Nodes上的Pods进行evict操作。
useTaintBasedEvictions - 在--feature-gates中指定，默认TaintBasedEvictions=false,仍属于Alpha特性。如果为true，则表示将通过Taint Nodes的方式来Evict Pods。