Autoscaler 中 VPA 的设计与实现

// vertical-pod-autoscaler/pkg/admission-controller/resource/pod/handler.go
func (h *resourceHandler) GetPatches(ar *admissionv1.AdmissionRequest) ([]resource_admission.PatchRecord, error) {        raw, namespace := ar.Object.Raw, ar.Namespace        pod := v1.Pod{}        err := json.Unmarshal(raw, &pod)        // ...            controllingVpa := h.vpaMatcher.GetMatchingVPA(&pod)  // 获取控制该 Pod 的 VPA 资源        patches := []resource_admission.PatchRecord{}
        for _, c := range h.patchCalculators {                partialPatches, err := c.CalculatePatches(&pod, controllingVpa)  // 根据每种 calculator 的计算方式返回 patch                patches = append(patches, partialPatches...)        }
        return patches, nil}

// vertical-pod-autoscaler/pkg/updater/logic/updater.go
func (u *updater) RunOnce(ctx context.Context) {        // ...
        vpaList, err := u.vpaLister.List(labels.Everything())  // 列出所有 VPA 资源        vpas := make([]*vpa_api_util.VpaWithSelector, 0)        for _, vpa := range vpaList {                selector, err := u.selectorFetcher.Fetch(vpa)                vpas = append(vpas, &vpa_api_util.VpaWithSelector{                        Vpa:      vpa,                        Selector: selector,                })        }
        podsList, err := u.podLister.List(labels.Everything())  // 列出所有 Pod 资源        allLivePods := filterDeletedPods(podsList)  // 过滤掉所有被删除的 Pod（即 DeletionTimestamp 不为空的）        controlledPods := make(map[*vpa_types.VerticalPodAutoscaler][]*apiv1.Pod)        for _, pod := range allLivePods {                controllingVPA := vpa_api_util.GetControllingVPAForPod(pod, vpas)  // 获取当前 Pod 对应的 VPA 资源                if controllingVPA != nil {                        controlledPods[controllingVPA.Vpa] = append(controlledPods[controllingVPA.Vpa], pod)                }        }
        for vpa, livePods := range controlledPods {                evictionLimiter := u.evictionFactory.NewPodsEvictionRestriction(livePods, vpa)                podsForUpdate := u.getPodsUpdateOrder(filterNonEvictablePods(livePods, evictionLimiter), vpa)  // 获取需要进行资源更新的 Pod 以进行驱逐                for _, pod := range podsForUpdate {                        if !evictionLimiter.CanEvict(pod) {  // 判断是否能驱逐                                continue                        }                        evictErr := evictionLimiter.Evict(pod, u.eventRecorder)  // 执行驱逐                }        }}

// vertical-pod-autoscaler/pkg/updater/priority/priority_processor.go
func (*defaultPriorityProcessor) GetUpdatePriority(pod *apiv1.Pod, _ *vpa_types.VerticalPodAutoscaler, recommendation *vpa_types.RecommendedPodResources) PodPriority {        // ...                totalRequestPerResource := make(map[apiv1.ResourceName]int64)      // 请求资源的总值，按资源类型分类        totalRecommendedPerResource := make(map[apiv1.ResourceName]int64)  // 推荐资源的总值，按资源类型分类
        for _, podContainer := range pod.Spec.Containers {                recommendedRequest := vpa_api_util.GetRecommendationForContainer(podContainer.Name, recommendation)  // 获取该容器对应的推荐值                    for resourceName, recommended := range recommendedRequest.Target {                        totalRecommendedPerResource[resourceName] += recommended.MilliValue()                        lowerBound, hasLowerBound := recommendedRequest.LowerBound[resourceName]                        upperBound, hasUpperBound := recommendedRequest.UpperBound[resourceName]                                                // 几种边界情况的判断...                }        }        resourceDiff := 0.0  // 所有资源类型差值的总和        for resource, totalRecommended := range totalRecommendedPerResource {                totalRequest := math.Max(float64(totalRequestPerResource[resource]), 1.0)                resourceDiff += math.Abs(totalRequest-float64(totalRecommended)) / totalRequest  // 对每种资源类型差值都进行了归一化        }        return PodPriority{                ResourceDiff:            resourceDiff,                // ...        }}

// vertical-pod-autoscaler/pkg/updater/eviction/pods_eviction_restriction.go
func (e *podsEvictionRestrictionImpl) CanEvict(pod *apiv1.Pod) bool {        cr, present := e.podToReplicaCreatorMap[getPodID(pod)]  // 根据 pod ID 找到其控制器        if present {                singleGroupStats, present := e.creatorToSingleGroupStatsMap[cr]                if pod.Status.Phase == apiv1.PodPending {                        return true  // 对于处于 Pending 状态的 Pod，可以被驱逐                }                if present {                        shouldBeAlive := singleGroupStats.configured - singleGroupStats.evictionTolerance  // 由 evictionToleranceFraction 控制，表示最多能驱逐的副本数                        if singleGroupStats.running-singleGroupStats.evicted > shouldBeAlive {                                return true  // 对于可容忍的驱逐数量之内，可以被驱逐                        }                        if singleGroupStats.running == singleGroupStats.configured &&                                singleGroupStats.evictionTolerance == 0 &&                                singleGroupStats.evicted == 0 {                                return true  // 若所有 Pods 都在运行，并且可容忍的驱逐数量过小，则只可以驱逐一个                        }                }        }        return false}