Kubernetes Node Controller源码分析之配置篇

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))
} 

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
}