kubelet 源码阅读(一)

func NewSourceApiserver(c clientset.Interface, nodeName types.NodeName, updates chan<- interface{}) {
	lw := cache.NewListWatchFromClient(c.CoreV1().RESTClient(), "pods", metav1.NamespaceAll, fields.OneTermEqualSelector(api.PodHostField, string(nodeName)))
	newSourceApiserverFromLW(lw, updates)
}
func newSourceApiserverFromLW(lw cache.ListerWatcher, updates chan<- interface{}) {
	send := func(objs []interface{}) {
		var pods []*v1.Pod
		for _, o := range objs {
			pods = append(pods, o.(*v1.Pod))
		}
		updates <- kubetypes.PodUpdate{Pods: pods, Op: kubetypes.SET, Source: kubetypes.ApiserverSource}
	}
	r := cache.NewReflector(lw, &v1.Pod{}, cache.NewUndeltaStore(send, cache.MetaNamespaceKeyFunc), 0)
	go r.Run(wait.NeverStop)
}

func (s *podStorage) Merge(source string, change interface{}) error {
	s.updateLock.Lock()
	defer s.updateLock.Unlock()

	seenBefore := s.sourcesSeen.Has(source)
	adds, updates, deletes, removes, reconciles := s.merge(source, change)
	firstSet := !seenBefore && s.sourcesSeen.Has(source)

	// deliver update notifications
	switch s.mode {
	case PodConfigNotificationIncremental:
		if len(removes.Pods) > 0 {
			s.updates <- *removes
		}
		if len(adds.Pods) > 0 {
			s.updates <- *adds
		}
		if len(updates.Pods) > 0 {
			s.updates <- *updates
		}
		if len(deletes.Pods) > 0 {
			s.updates <- *deletes
		}
		if firstSet && len(adds.Pods) == 0 && len(updates.Pods) == 0 && len(deletes.Pods) == 0 {
			// Send an empty update when first seeing the source and there are
			// no ADD or UPDATE or DELETE pods from the source. This signals kubelet that
			// the source is ready.
			s.updates <- *adds
		}
		// Only add reconcile support here, because kubelet doesn't support Snapshot update now.
		if len(reconciles.Pods) > 0 {
			s.updates <- *reconciles
		}

	case PodConfigNotificationSnapshotAndUpdates:
		if len(removes.Pods) > 0 || len(adds.Pods) > 0 || firstSet {
			s.updates <- kubetypes.PodUpdate{Pods: s.MergedState().([]*v1.Pod), Op: kubetypes.SET, Source: source}
		}
		if len(updates.Pods) > 0 {
			s.updates <- *updates
		}
		if len(deletes.Pods) > 0 {
			s.updates <- *deletes
		}

	case PodConfigNotificationSnapshot:
		if len(updates.Pods) > 0 || len(deletes.Pods) > 0 || len(adds.Pods) > 0 || len(removes.Pods) > 0 || firstSet {
			s.updates <- kubetypes.PodUpdate{Pods: s.MergedState().([]*v1.Pod), Op: kubetypes.SET, Source: source}
		}

	case PodConfigNotificationUnknown:
		fallthrough
	default:
		panic(fmt.Sprintf("unsupported PodConfigNotificationMode: %#v", s.mode))
	}

	return nil
}

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
}

func (p *podWorkers) UpdatePod(options *UpdatePodOptions) {
	pod := options.Pod
	uid := pod.UID
	var podUpdates chan UpdatePodOptions
	var exists bool

	p.podLock.Lock()
	defer p.podLock.Unlock()
	if podUpdates, exists = p.podUpdates[uid]; !exists {
		podUpdates = make(chan UpdatePodOptions, 1)
		p.podUpdates[uid] = podUpdates
		go func() {
			defer runtime.HandleCrash()
			p.managePodLoop(podUpdates)
		}()
	}
	if !p.isWorking[pod.UID] {
		p.isWorking[pod.UID] = true
		podUpdates <- *options
	} else {
		update, found := p.lastUndeliveredWorkUpdate[pod.UID]
		if !found || update.UpdateType != kubetypes.SyncPodKill {
			p.lastUndeliveredWorkUpdate[pod.UID] = *options
		}
	}
}

// SyncPod syncs the running pod into the desired pod by executing following steps:
//
//  1. Compute sandbox and container changes.
//  2. Kill pod sandbox if necessary.
//  3. Kill any containers that should not be running.
//  4. Create sandbox if necessary.
//  5. Create ephemeral containers.
//  6. Create init containers.
//  7. Create normal containers.
func (m *kubeGenericRuntimeManager) SyncPod(pod *v1.Pod, podStatus *kubecontainer.PodStatus, pullSecrets []v1.Secret, backOff *flowcontrol.Backoff) (result kubecontainer.PodSyncResult) {
	// Step 1: Compute sandbox and container changes.
	podContainerChanges := m.computePodActions(pod, podStatus)
	klog.V(3).Infof("computePodActions got %+v for pod %q", podContainerChanges, format.Pod(pod))
	if podContainerChanges.CreateSandbox {
		ref, err := ref.GetReference(legacyscheme.Scheme, pod)
		if err != nil {
			klog.Errorf("Couldn't make a ref to pod %q: '%v'", format.Pod(pod), err)
		}
		if podContainerChanges.SandboxID != "" {
			m.recorder.Eventf(ref, v1.EventTypeNormal, events.SandboxChanged, "Pod sandbox changed, it will be killed and re-created.")
		} else {
			klog.V(4).Infof("SyncPod received new pod %q, will create a sandbox for it", format.Pod(pod))
		}
	}
//省略
}