复制集-控制器为什么需要burstReplicas

Question

我正在研究kubernetes自愈函数。我想知道rsc.burstReplicas的意思

func (rsc *ReplicaSetController) manageReplicas(filteredPods []*v1.Pod, rs *apps.ReplicaSet) error {
    diff := len(filteredPods) - int(*(rs.Spec.Replicas))
    rsKey, err := controller.KeyFunc(rs)
    if err != nil {
        utilruntime.HandleError(fmt.Errorf("Couldn't get key for %v %#v: %v", rsc.Kind, rs, err))
        return nil
    }
    if diff < 0 {
        diff *= -1
        if diff > rsc.burstReplicas {
            diff = rsc.burstReplicas
        }
~~~

Answer 1

我将猜测这实际上是kubernetes的核心；当前状态与期望状态。和burstReplicas是它可以一次创建或删除的副本的数量。

1.-检查当前pod数量是否高于或低于所需数量：

diff := len(filteredPods) - int(*(rs.Spec.Replicas))

2.-如果在下面，则需要创建pods。但首先，它将检查您想要创建的pod数量是高于还是低于它可以创建的最大pod数量(500)。

if diff < 0 {
    diff *= -1
    if diff > rsc.burstReplicas {          # If you need more then 500 pods,
        diff = rsc.burstReplicas           # it is going to create 500.
    }                                      # Then, will check again

3.-如果它在上面，它需要杀死pod，但再次，它需要检查它需要杀死的pod数量是否超过了它可以杀死的最大数量：

} else if diff > 0 {
    if diff > rsc.burstReplicas {
        diff = rsc.burstReplicas
    }