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如何避免container頻繁地restart?相信大部分人都還沒(méi)學(xué)會(huì)這個(gè)技能,為了讓大家學(xué)會(huì),給大家總結(jié)了以下內(nèi)容,話不多說(shuō),一起往下看吧。
分析:
kubernetes/pkg/kubelet/kubelet.go
通過(guò)源碼發(fā)現(xiàn),kubernetes/pkg/kubelet/kubelet.go 文件中有兩個(gè)常量:
MaxContainerBackOff = 300 * time.Second
backOffPeriod = time.Second * 10
使用這兩個(gè)變量構(gòu)造了一個(gè) BackOff 對(duì)象,這個(gè)是 kubelet 的屬性,對(duì)該 node 上所有 pod 都適用
klet.backOff = flowcontrol.NewBackOff(backOffPeriod, MaxContainerBackOff)
BackOff 結(jié)構(gòu)如下
type Backoff struct {
sync.Mutex
Clock clock.Clock
defaultDuration time.Duration
maxDuration time.Duration
perItemBackoff map[string]*backoffEntry
}
然后在 SyncPod 方法中使用這個(gè)對(duì)象
// Call the container runtime's SyncPod callback
result := kl.containerRuntime.SyncPod(pod, apiPodStatus, podStatus, pullSecrets, kl.backOff)
SyncPod 具體做的事有:
// 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 init containers.
// 6. Create normal containers.
func (m *kubeGenericRuntimeManager) SyncPod(pod *v1.Pod, _ v1.PodStatus, podStatus *kubecontainer.PodStatus, pullSecrets []v1.Secret, backOff *flowcontrol.Backoff) (result kubecontainer.PodSyncResult) {
同樣在這個(gè)文件中,有一個(gè)關(guān)鍵的函數(shù)
// If a container is still in backoff, the function will return a brief backoff error and
// a detailed error message.
func (m *kubeGenericRuntimeManager) doBackOff(pod *v1.Pod, container *v1.Container, podStatus *kubecontainer.PodStatus, backOff *flowcontrol.Backoff) (bool, string, error) {
var cStatus *kubecontainer.ContainerStatus
for _, c := range podStatus.ContainerStatuses {
if c.Name == container.Name && c.State == kubecontainer.ContainerStateExited {
cStatus = c
break
}
}
if cStatus == nil {
return false, "", nil
}
glog.Infof("checking backoff for container %q in pod %q", container.Name, format.Pod(pod))
// Use the finished time of the latest exited container as the start point to calculate whether to do back-off.
ts := cStatus.FinishedAt
// backOff requires a unique key to identify the container.
key := getStableKey(pod, container)
if backOff.IsInBackOffSince(key, ts) {
if ref, err := kubecontainer.GenerateContainerRef(pod, container); err == nil {
m.recorder.Eventf(ref, v1.EventTypeWarning, events.BackOffStartContainer, "Back-off restarting failed container")
}
err := fmt.Errorf("Back-off %s restarting failed container=%s pod=%s", backOff.Get(key), container.Name, format.Pod(pod))
glog.Infof("%s", err.Error())
return true, err.Error(), kubecontainer.ErrCrashLoopBackOff
}
backOff.Next(key, ts)
return false, "", nil
}
其中 backOff.Next 函數(shù)定義如下
// move backoff to the next mark, capping at maxDuration
func (p *Backoff) Next(id string, eventTime time.Time) {
p.Lock()
defer p.Unlock()
entry, ok := p.perItemBackoff[id]
if !ok || hasExpired(eventTime, entry.lastUpdate, p.maxDuration) {
entry = p.initEntryUnsafe(id)
} else {
delay := entry.backoff * 2 // exponential
entry.backoff = time.Duration(integer.Int64Min(int64(delay), int64(p.maxDuration)))
}
entry.lastUpdate = p.Clock.Now()
}
看完上述內(nèi)容,你們掌握避免container頻繁地restart的方法了嗎?如果還想學(xué)到更多技能或想了解更多相關(guān)內(nèi)容,歡迎關(guān)注億速云行業(yè)資訊頻道,感謝各位的閱讀!
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