# P3-Controller分类与Deployment Controller
## 前言
Controller部分的第一篇文章中， ， ， ：
[Controller-P1-多实例leader选举 ](https://wqyin.cn/gitbooks/kubeSourceCodeNote/controller/Kubernetes源码学习-Controller-P1-多实例leader选举.html )
接着在第二篇中， ， ：
[Controller-P2-Controller与informer ](https://wqyin.cn/gitbooks/kubeSourceCodeNote/controller/Kubernetes源码学习-Controller-P2-Controller与informer.html )
那么本篇，就接着第一篇往下，继续看代码。
## Controller的分类
**启动**
承接篇一， ， ：
`cmd/kube-controller-manager/app/controllermanager.go:191`
```go
run := func(ctx context.Context) {}
```
==> `cmd/kube-controller-manager/app/controllermanager.go:217` ，重点是这里的**NewControllerInitializers**函数。
```go
if err := StartControllers(controllerContext, saTokenControllerInitFunc, NewControllerInitializers(controllerContext.LoopMode), unsecuredMux); err != nil {
klog.Fatalf("error starting controllers: %v", err)
}
```
==> `cmd/kube-controller-manager/app/controllermanager.go:343`
< img src = "http://mycloudn.wqyin.cn/20200127122642.png" style = "zoom:80%;" / >
可以看到， ， ， ， ， ， ， ，
## Deployment Controller
### 初始化
`cmd/kube-controller-manager/app/controllermanager.go:354`
```go
controllers["deployment"] = startDeploymentController
```
==> `cmd/kube-controller-manager/app/apps.go:82`
```go
func startDeploymentController(ctx ControllerContext) (http.Handler, bool, error) {
if !ctx.AvailableResources[schema.GroupVersionResource{Group: "apps", Version: "v1", Resource: "deployments"}] {
return nil, false, nil
}
dc, err := deployment.NewDeploymentController(
// deployment主要关注这3个资源: Deployment/ReplicaSet/Pod，
// 这3个函数会返回相应资源的informer
ctx.InformerFactory.Apps().V1().Deployments(),
ctx.InformerFactory.Apps().V1().ReplicaSets(),
ctx.InformerFactory.Core().V1().Pods(),
ctx.ClientBuilder.ClientOrDie("deployment-controller"),
)
if err != nil {
return nil, true, fmt.Errorf("error creating Deployment controller: %v", err)
// deployment controller 运行函数
go dc.Run(int(ctx.ComponentConfig.DeploymentController.ConcurrentDeploymentSyncs), ctx.Stop)
return nil, true, nil
}
```
dc.Run()函数， ， ， ： ， ，
==> `pkg/controller/deployment/deployment_controller.go:148`
```go
// Run begins watching and syncing.
func (dc *DeploymentController) Run(workers int, stopCh < -chan struct { } ) {
defer utilruntime.HandleCrash()
defer dc.queue.ShutDown()
klog.Infof("Starting deployment controller")
defer klog.Infof("Shutting down deployment controller")
// 判断各个informer的缓存是否已经同步完毕的函数
if !controller.WaitForCacheSync("deployment", stopCh, dc.dListerSynced, dc.rsListerSynced, dc.podListerSynced) {
return
}
// 启动多个worker开始工作
for i := 0; i < workers ; i + + {
go wait.Until(dc.worker, time.Second, stopCh)
}
< -stopCh
}
```
controller.WaitForCacheSync函数是用来检测各个informer是否本地缓存已经同步完毕的函数， ， ， ，
默认是5个worker， ， ， ， ，
#### wait.Until循环计时器函数
`pkg/controller/deployment/deployment_controller.go:160`
==> `vendor/k8s.io/apimachinery/pkg/util/wait/wait.go:88`
==>`vendor/k8s.io/apimachinery/pkg/util/wait/wait.go:130`
```go
func JitterUntil(f func(), period time.Duration, jitterFactor float64, sliding bool, stopCh < -chan struct { } ) {
var t *time.Timer
var sawTimeout bool
for {
select {
case < -stopCh:
return
default:
}
jitteredPeriod := period
if jitterFactor > 0.0 {
jitteredPeriod = Jitter(period, jitterFactor)
}
// sliding这个布尔值的意思是是否将执行函数f()的执行时间计入执行间隔时间内， ， ， ，
if !sliding {
t = resetOrReuseTimer(t, jitteredPeriod, sawTimeout)
}
func() {
defer runtime.HandleCrash()
f()
}()
if sliding {
t = resetOrReuseTimer(t, jitteredPeriod, sawTimeout)
}
// select 下各个分支的权重是公平的， ， ，
select {
case < -stopCh:
return
// Timer.C是Timer结构体内部的一个channel， ， ， ： ，
case < -t.C:
sawTimeout = true
}
}
}
```
resetOrReuseTimer函数：
```go
func resetOrReuseTimer(t *time.Timer, d time.Duration, sawTimeout bool) *time.Timer {
if t == nil {
return time.NewTimer(d)
}
if !t.Stop() & & !sawTimeout {
< -t.C
}
t.Reset(d)
return t
}
```
概括一下， ， ，
#### dc.worker函数
`pkg/controller/deployment/deployment_controller.go:460`
==> `pkg/controller/deployment/deployment_controller.go:464`
```go
func (dc *DeploymentController) processNextWorkItem() bool {
// 从队列头部取出对象
key, quit := dc.queue.Get()
if quit {
return false
}
defer dc.queue.Done(key)
// 处理对象
err := dc.syncHandler(key.(string))
dc.handleErr(err, key)
return true
}
```
Deployment controller 的worker函数就是不断地调用processNextWorkItem函数，
其中dc.queue.Get()接口方法的实现在这里：
`vendor/k8s.io/client-go/util/workqueue/queue.go:140`
```go
func (q *Type) Get() (item interface{}, shutdown bool) {
q.cond.L.Lock()
defer q.cond.L.Unlock()
for len(q.queue) == 0 & & !q.shuttingDown {
q.cond.Wait()
}
if len(q.queue) == 0 {
// We must be shutting down.
return nil, true
}
// 取出队列的队首
item, q.queue = q.queue[0], q.queue[1:]
q.metrics.get(item)
// 对象加入正在处理中map
q.processing.insert(item)
// dirty map去除对象(dirty map中保存的是等待处理的对象)
q.dirty.delete(item)
return item, false
}
```
其中的`dc.syncHandler()`方法在这里：
pkg/controller/deployment/deployment_controller.go:135
```go
dc.syncHandler = dc.syncDeployment
```
==> pkg/controller/deployment/deployment_controller.go:560
所有的增删改(滚动更新)查操作，全部都在这个函数内部处理。
```go
func (dc *DeploymentController) syncDeployment(key string) error {
startTime := time.Now()
klog.V(4).Infof("Started syncing deployment %q (%v)", key, startTime)
defer func() {
klog.V(4).Infof("Finished syncing deployment %q (%v)", key, time.Since(startTime))
}()
namespace, name, err := cache.SplitMetaNamespaceKey(key)
if err != nil {
return err
}
deployment, err := dc.dLister.Deployments(namespace).Get(name)
if errors.IsNotFound(err) {
klog.V(2).Infof("Deployment %v has been deleted", key)
return nil
}
if err != nil {
return err
}
// Deep-copy otherwise we are mutating our cache.
// TODO: Deep-copy only when needed.
d := deployment.DeepCopy()
everything := metav1.LabelSelector{}
if reflect.DeepEqual(d.Spec.Selector, & everything) {
// deployment必须包含selector标签
dc.eventRecorder.Eventf(d, v1.EventTypeWarning, "SelectingAll", "This deployment is selecting all pods. A non-empty selector is required.")
if d.Status.ObservedGeneration < d.Generation {
d.Status.ObservedGeneration = d.Generation
dc.client.AppsV1().Deployments(d.Namespace).UpdateStatus(d)
}
return nil
}
// 获取deployment所控制的replicaSet
rsList, err := dc.getReplicaSetsForDeployment(d)
if err != nil {
return err
}
// 获取所有的pod， ， ，
// 检查deployment在重建的过程中是否还存在旧版本(未更新)的pod
podMap, err := dc.getPodMapForDeployment(d, rsList)
if err != nil {
return err
}
if d.DeletionTimestamp != nil {
return dc.syncStatusOnly(d, rsList)
}
// 检查deployment是否为pause暂停状态，
if err = dc.checkPausedConditions(d); err != nil {
return err
}
if d.Spec.Paused {
return dc.sync(d, rsList)
}
// 判断本次deployment事件是否是一个回滚事件
// 一旦底层的rs更新到了一个新的版本， ， ， ， ， ， ，
if getRollbackTo(d) != nil {
return dc.rollback(d, rsList)
}
// 判断本次deployment事件是否是一个scale事件，
scalingEvent, err := dc.isScalingEvent(d, rsList)
if err != nil {
return err
}
if scalingEvent {
return dc.sync(d, rsList)
}
// 更新deployment，
// 1.如果是rolloutRecreate类型，
// 2.如果是rolloutRolling类型，
switch d.Spec.Strategy.Type {
case apps.RecreateDeploymentStrategyType:
return dc.rolloutRecreate(d, rsList, podMap)
case apps.RollingUpdateDeploymentStrategyType:
return dc.rolloutRolling(d, rsList)
}
return fmt.Errorf("unexpected deployment strategy type: %s", d.Spec.Strategy.Type)
}
```
### 暂停和扩(缩)容(/删除)
dc.sync方法这里出现了两次， ， ，
`pkg/controller/deployment/sync.go:48`
```go
func (dc *DeploymentController) sync(d *apps.Deployment, rsList []*apps.ReplicaSet) error {
// 展开查看代码， ， ， ，
newRS, oldRSs, err := dc.getAllReplicaSetsAndSyncRevision(d, rsList, false)
if err != nil {
return err
}
// 对比最新的rs和之前的rs， ，
if err := dc.scale(d, newRS, oldRSs); err != nil {
// If we get an error while trying to scale, the deployment will be requeued
// so we can abort this resync
return err
}
// pause状态， ，
if d.Spec.Paused & & getRollbackTo(d) == nil {
if err := dc.cleanupDeployment(oldRSs, d); err != nil {
return err
}
}
allRSs := append(oldRSs, newRS)
// 同步deployment状态
return dc.syncDeploymentStatus(allRSs, newRS, d)
}
```
来看看dc.scale()方法：
`pkg/controller/deployment/sync.go:289`
```go
func (dc *DeploymentController) scale(deployment *apps.Deployment, newRS *apps.ReplicaSet, oldRSs []*apps.ReplicaSet) error {
// FindActiveOrLatest方法返回值： ， ， ，
if activeOrLatest := deploymentutil.FindActiveOrLatest(newRS, oldRSs); activeOrLatest != nil {
if *(activeOrLatest.Spec.Replicas) == * (deployment.Spec.Replicas) {
// 如果rs已经和deployment指定的副本数一致，
return nil
}
_, _ , err := dc.scaleReplicaSetAndRecordEvent(activeOrLatest, *(deployment.Spec.Replicas), deployment)
return err
}
// 如果最新的rs的已经收敛到了deployment的期望状态，
if deploymentutil.IsSaturated(deployment, newRS) {
for _, old := range controller.FilterActiveReplicaSets(oldRSs) {
if _, _ , err := dc.scaleReplicaSetAndRecordEvent(old, 0, deployment); err != nil {
return err
}
}
return nil
}
// 在滚动更新的过程中， ， ， ，
if deploymentutil.IsRollingUpdate(deployment) {
allRSs := controller.FilterActiveReplicaSets(append(oldRSs, newRS))
allRSsReplicas := deploymentutil.GetReplicaCountForReplicaSets(allRSs)
allowedSize := int32(0)
if *(deployment.Spec.Replicas) > 0 {
allowedSize = *(deployment.Spec.Replicas) + deploymentutil.MaxSurge(*deployment)
}
// 可以增加或删除的pod数量， ，
deploymentReplicasToAdd := allowedSize - allRSsReplicas
var scalingOperation string
switch {
case deploymentReplicasToAdd > 0:
// 如果是扩容，
sort.Sort(controller.ReplicaSetsBySizeNewer(allRSs))
scalingOperation = "up"
case deploymentReplicasToAdd < 0:
// 如果是缩容，
sort.Sort(controller.ReplicaSetsBySizeOlder(allRSs))
scalingOperation = "down"
}
// 遍历每一个rs, 用map保存此rs应该达到的pod的数量(等于当前数量+需scale数量）
deploymentReplicasAdded := int32(0)
nameToSize := make(map[string]int32)
for i := range allRSs {
rs := allRSs[i]
if deploymentReplicasToAdd != 0 {
// 计算当前rs需scale的数量
proportion := deploymentutil.GetProportion(rs, *deployment, deploymentReplicasToAdd, deploymentReplicasAdded)
// 总pod数量等于当前数量+scale数量
nameToSize[rs.Name] = *(rs.Spec.Replicas) + proportion
deploymentReplicasAdded += proportion
} else {
nameToSize[rs.Name] = *(rs.Spec.Replicas)
}
}
// Update all replica sets
for i := range allRSs {
rs := allRSs[i]
// Add/remove any leftovers to the largest replica set.
// 如果还有各rs加起来都未消化完的pod，
if i == 0 & & deploymentReplicasToAdd != 0 {
leftover := deploymentReplicasToAdd - deploymentReplicasAdded
nameToSize[rs.Name] = nameToSize[rs.Name] + leftover
if nameToSize[rs.Name] < 0 {
nameToSize[rs.Name] = 0
}
}
// 把这个rs scale到它应该达到的数量
if _, _ , err := dc.scaleReplicaSet(rs, nameToSize[rs.Name], deployment, scalingOperation); err != nil {
// Return as soon as we fail, the deployment is requeued
return err
}
}
}
return nil
}
```
#### syncDeploymentStatus函数
在完成rs的scale和pause状态的逻辑处理后， ，
```go
func (dc *DeploymentController) syncDeploymentStatus(allRSs []*apps.ReplicaSet, newRS *apps.ReplicaSet, d *apps.Deployment) error {
newStatus := calculateStatus(allRSs, newRS, d)
if reflect.DeepEqual(d.Status, newStatus) {
return nil
}
newDeployment := d
newDeployment.Status = newStatus
_, err := dc.client.AppsV1().Deployments(newDeployment.Namespace).UpdateStatus(newDeployment)
return err
}
```
这个函数主要用来更新deployment的status字段的内容，
整个扩容的过程涉及所有rs的操作， ， ， ， ， ，
### 滚动更新
Deployment更新策略分为滚动更新和一次性更新， ， ， ，
deployment 的spec字段内的内容一旦发生变化， ， ， ，
`pkg/controller/deployment/deployment_controller.go:644`
==> `pkg/controller/deployment/rolling.go:31`
```go
func (dc *DeploymentController) rolloutRolling(d *apps.Deployment, rsList []*apps.ReplicaSet) error {
// 获取新的rs，
newRS, oldRSs, err := dc.getAllReplicaSetsAndSyncRevision(d, rsList, true)
if err != nil {
return err
}
allRSs := append(oldRSs, newRS)
// 对比判断newRS是否需要扩容(新rs管理的pod是否已达到目标数量)
scaledUp, err := dc.reconcileNewReplicaSet(allRSs, newRS, d)
if err != nil {
return err
}
if scaledUp {
// 扩容完毕，
return dc.syncRolloutStatus(allRSs, newRS, d)
}
// 对比判断oldRS是否需要缩容(旧rs管理的pod是否已经全部终结)
scaledDown, err := dc.reconcileOldReplicaSets(allRSs, controller.FilterActiveReplicaSets(oldRSs), newRS, d)
if err != nil {
return err
}
if scaledDown {
// 缩容完毕，
return dc.syncRolloutStatus(allRSs, newRS, d)
}
// deployment 进入complete状态， ，
if deploymentutil.DeploymentComplete(d, & d.Status) {
if err := dc.cleanupDeployment(oldRSs, d); err != nil {
return err
}
}
// 更新deployment的status
return dc.syncRolloutStatus(allRSs, newRS, d)
}
```
reconcileNewReplicaSet函数：
这个函数返回bool值，
```go
func (dc *DeploymentController) reconcileNewReplicaSet(allRSs []*apps.ReplicaSet, newRS *apps.ReplicaSet, deployment *apps.Deployment) (bool, error) {
if *(newRS.Spec.Replicas) == * (deployment.Spec.Replicas) {
// deployment replicas 和newRS replicas相等，
return false, nil
}
if *(newRS.Spec.Replicas) > * (deployment.Spec.Replicas) {
// newRS replicas > deployment replicas,则说明newRS需要缩容，
scaled, _, err := dc.scaleReplicaSetAndRecordEvent(newRS, *(deployment.Spec.Replicas), deployment)
return scaled, err
}
// newRS replicas < deployment replicas , 则 使 用 NewRSNewReplicas 方 法 计 算 newRS 此 时 应 用 拥 有 的 pod 副 本 的 数 量
newReplicasCount, err := deploymentutil.NewRSNewReplicas(deployment, allRSs, newRS)
if err != nil {
return false, err
}
// 返回值scaled此时值应当是true
scaled, _, err := dc.scaleReplicaSetAndRecordEvent(newRS, newReplicasCount, deployment)
return scaled, err
}
```
NewRSNewReplicas函数：
计算newRS此时应该有的副本数量的函数
```go
func NewRSNewReplicas(deployment *apps.Deployment, allRSs []*apps.ReplicaSet, newRS *apps.ReplicaSet) (int32, error) {
switch deployment.Spec.Strategy.Type {
// 滚动更新时
case apps.RollingUpdateDeploymentStrategyType:
// Check if we can scale up.
maxSurge, err := intstrutil.GetValueFromIntOrPercent(deployment.Spec.Strategy.RollingUpdate.MaxSurge, int(*(deployment.Spec.Replicas)), true)
if err != nil {
return 0, err
}
// 当前的副本数(当前值) = 所有版本的rs管理的pod数量的总和
currentPodCount := GetReplicaCountForReplicaSets(allRSs)
// 最多允许同时存在的副本数(最大值) = 指定副本数 + maxSurge的副本数(整数或者比例计算)
maxTotalPods := *(deployment.Spec.Replicas) + int32(maxSurge)
// 如果当前值比最大值还大， ，
if currentPodCount >= maxTotalPods {
return *(newRS.Spec.Replicas), nil
}
// 否则，可扩容值 = 最大值 - 当前值
scaleUpCount := maxTotalPods - currentPodCount
// 但每一个版本的rs管理的副本数量， ， ，
scaleUpCount = int32(integer.IntMin(int(scaleUpCount), int(*(deployment.Spec.Replicas)-*(newRS.Spec.Replicas))))
// 此时newRS应有的副本数 = 当前值 + 可扩容值
return *(newRS.Spec.Replicas) + scaleUpCount, nil
case apps.RecreateDeploymentStrategyType:
// 非滚动更新时，
return *(deployment.Spec.Replicas), nil
default:
return 0, fmt.Errorf("deployment type %v isn't supported", deployment.Spec.Strategy.Type)
}
}
```
reconcileOldReplicaSets函数
这个函数返回bool值，
```go
func (dc *DeploymentController) reconcileOldReplicaSets(allRSs []*apps.ReplicaSet, oldRSs []*apps.ReplicaSet, newRS *apps.ReplicaSet, deployment *apps.Deployment) (bool, error) {
oldPodsCount := deploymentutil.GetReplicaCountForReplicaSets(oldRSs)
if oldPodsCount == 0 {
// 已经缩容完毕，直接返回
return false, nil
}
// 当前所有的pod的数量(当前值)
allPodsCount := deploymentutil.GetReplicaCountForReplicaSets(allRSs)
klog.V(4).Infof("New replica set %s/%s has %d available pods.", newRS.Namespace, newRS.Name, newRS.Status.AvailableReplicas)
// deployment 指定的最大不可用的副本数(最大不可用值)
maxUnavailable := deploymentutil.MaxUnavailable(*deployment)
// Check if we can scale down. We can scale down in the following 2 cases:
// * Some old replica sets have unhealthy replicas, we could safely scale down those unhealthy replicas since that won't further
// increase unavailability.
// * New replica set has scaled up and it's replicas becomes ready, then we can scale down old replica sets in a further step.
//
// maxScaledDown := allPodsCount - minAvailable - newReplicaSetPodsUnavailable
// take into account not only maxUnavailable and any surge pods that have been created, but also unavailable pods from
// the newRS, so that the unavailable pods from the newRS would not make us scale down old replica sets in a further
// step(that will increase unavailability).
//
// Concrete example:
//
// * 10 replicas
// * 2 maxUnavailable (absolute number, not percent)
// * 3 maxSurge (absolute number, not percent)
//
// case 1:
// * Deployment is updated, newRS is created with 3 replicas, oldRS is scaled down to 8, and newRS is scaled up to 5.
// * The new replica set pods crashloop and never become available.
// * allPodsCount is 13. minAvailable is 8. newRSPodsUnavailable is 5.
// * A node fails and causes one of the oldRS pods to become unavailable. However, 13 - 8 - 5 = 0, so the oldRS won't be scaled down.
// * The user notices the crashloop and does kubectl rollout undo to rollback.
// * newRSPodsUnavailable is 1, since we rolled back to the good replica set, so maxScaledDown = 13 - 8 - 1 = 4. 4 of the crashlooping pods will be scaled down.
// * The total number of pods will then be 9 and the newRS can be scaled up to 10.
//
// case 2:
// Same example, but pushing a new pod template instead of rolling back (aka "roll over"):
// * The new replica set created must start with 0 replicas because allPodsCount is already at 13.
// * However, newRSPodsUnavailable would also be 0, so the 2 old replica sets could be scaled down by 5 (13 - 8 - 0), which would then
// allow the new replica set to be scaled up by 5.
// Available指的是就绪探针结果为true的副本， ，
// 最小可用副本数(至少可用数)
minAvailable := *(deployment.Spec.Replicas) - maxUnavailable
// newRs不可用数
newRSUnavailablePodCount := *(newRS.Spec.Replicas) - newRS.Status.AvailableReplicas
// 最大可缩容数 = 总数 - 最小可用数 - newRS不可用数(为了保证最小可用数，
maxScaledDown := allPodsCount - minAvailable - newRSUnavailablePodCount
if maxScaledDown < = 0 {
return false, nil
}
// oldRS里不健康的副本，
// and cause timeout. See https://github.com/kubernetes/kubernetes/issues/16737
oldRSs, cleanupCount, err := dc.cleanupUnhealthyReplicas(oldRSs, deployment, maxScaledDown)
if err != nil {
return false, nil
}
klog.V(4).Infof("Cleaned up unhealthy replicas from old RSes by %d", cleanupCount)
// 还要对比最大可缩容数和deployment指定的最大同时不可用副本数， ，
allRSs = append(oldRSs, newRS)
scaledDownCount, err := dc.scaleDownOldReplicaSetsForRollingUpdate(allRSs, oldRSs, deployment)
if err != nil {
return false, nil
}
klog.V(4).Infof("Scaled down old RSes of deployment %s by %d", deployment.Name, scaledDownCount)
// oldRS里不健康的副本，
totalScaledDown := cleanupCount + scaledDownCount
// 判断缩容数是否大于0
return totalScaledDown > 0, nil
}
```
中间的英文注释里的举例说明非常详细，可以看一下注释。
#### syncRolloutStatus函数
这个函数主要用于更新deployment的status字段和其中的condition字段。
```go
func (dc *DeploymentController) syncRolloutStatus(allRSs []*apps.ReplicaSet, newRS *apps.ReplicaSet, d *apps.Deployment) error {
newStatus := calculateStatus(allRSs, newRS, d)
if !util.HasProgressDeadline(d) {
util.RemoveDeploymentCondition(& newStatus, apps.DeploymentProgressing)
}
currentCond := util.GetDeploymentCondition(d.Status, apps.DeploymentProgressing)
/**
判断deployment是否为complete状态， ：
1. newRS.replicas = newRS.Status.UpdatedReplicas 说明newRS的副本更新已全部完成
2. newRS.status.condition.reason = miniumReplicasAvailable
** /
isCompleteDeployment := newStatus.Replicas == newStatus.UpdatedReplicas & & currentCond != nil & & currentCond.Reason == util.NewRSAvailableReason
// 未达到complete状态的deployment，
if util.HasProgressDeadline(d) & & !isCompleteDeployment {
switch {
case util.DeploymentComplete(d, & newStatus):
// Update the deployment conditions with a message for the new replica set that
// was successfully deployed. If the condition already exists, we ignore this update.
msg := fmt.Sprintf("Deployment %q has successfully progressed.", d.Name)
if newRS != nil {
msg = fmt.Sprintf("ReplicaSet %q has successfully progressed.", newRS.Name)
}
condition := util.NewDeploymentCondition(apps.DeploymentProgressing, v1.ConditionTrue, util.NewRSAvailableReason, msg)
util.SetDeploymentCondition(& newStatus, *condition)
case util.DeploymentProgressing(d, & newStatus):
// If there is any progress made, continue by not checking if the deployment failed. This
// behavior emulates the rolling updater progressDeadline check.
msg := fmt.Sprintf("Deployment %q is progressing.", d.Name)
if newRS != nil {
msg = fmt.Sprintf("ReplicaSet %q is progressing.", newRS.Name)
}
condition := util.NewDeploymentCondition(apps.DeploymentProgressing, v1.ConditionTrue, util.ReplicaSetUpdatedReason, msg)
// Update the current Progressing condition or add a new one if it doesn't exist.
// If a Progressing condition with status=true already exists, we should update
// everything but lastTransitionTime. SetDeploymentCondition already does that but
// it also is not updating conditions when the reason of the new condition is the
// same as the old. The Progressing condition is a special case because we want to
// update with the same reason and change just lastUpdateTime iff we notice any
// progress. That's why we handle it here.
if currentCond != nil {
if currentCond.Status == v1.ConditionTrue {
condition.LastTransitionTime = currentCond.LastTransitionTime
}
util.RemoveDeploymentCondition(& newStatus, apps.DeploymentProgressing)
}
util.SetDeploymentCondition(& newStatus, *condition)
case util.DeploymentTimedOut(d, & newStatus):
// Update the deployment with a timeout condition. If the condition already exists,
// we ignore this update.
msg := fmt.Sprintf("Deployment %q has timed out progressing.", d.Name)
if newRS != nil {
msg = fmt.Sprintf("ReplicaSet %q has timed out progressing.", newRS.Name)
}
condition := util.NewDeploymentCondition(apps.DeploymentProgressing, v1.ConditionFalse, util.TimedOutReason, msg)
util.SetDeploymentCondition(& newStatus, *condition)
}
}
```
DeploymentCondition在这里面反复出现， ，
< img src = "http://mycloudn.wqyin.cn/20200130125357.png" style = "zoom:50%;" / >
#### 总结
滚动更新过程中主要是通过调用`reconcileNewReplicaSet`函数对 newRS 扩容，调用 `reconcileOldReplicaSets` 函数 对 oldRSs缩容， `maxSurge` 和 `maxUnavailable` 的约束， ， ，
## 总结
Deployment的回滚、扩(缩)容、暂停、更新等操作， ， ， ， ， ，
另外， ， ， ，
