188 lines
7.2 KiB
Markdown
188 lines
7.2 KiB
Markdown
---
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title: 从轮询切换为基于 CRI 事件的更新来获取容器状态
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min-kubernetes-server-version: 1.26
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content_type: task
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weight: 90
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---
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<!--
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title: Switching from Polling to CRI Event-based Updates to Container Status
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min-kubernetes-server-version: 1.26
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content_type: task
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weight: 90
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-->
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{{< feature-state for_k8s_version="v1.27" state="beta" >}}
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<!-- overview -->
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<!--
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This page shows how to migrate nodes to use event based updates for container status. The event-based
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implementation reduces node resource consumption by the kubelet, compared to the legacy approach
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that relies on polling.
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You may know this feature as _evented Pod lifecycle event generator (PLEG)_. That's the name used
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internally within the Kubernetes project for a key implementation detail.
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The polling based approach is referred to as _generic PLEG_.
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-->
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本页展示了如何迁移节点以使用基于事件的更新来获取容器状态。
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与依赖轮询的传统方法相比，基于事件的实现可以减少 kubelet 对节点资源的消耗。
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你可以将这个特性称为**事件驱动的 Pod 生命周期事件生成器 (PLEG)**。
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这是在 Kubernetes 项目内部针对关键实现细节所用的名称。
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基于轮询的方法称为**通用 PLEG**。
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## {{% heading "prerequisites" %}}
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<!--
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* You need to run a version of Kubernetes that provides this feature.
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Kubernetes v1.27 includes beta support for event-based container
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status updates. The feature is beta but is _disabled_ by default
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because it requires support from the container runtime.
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* {{< version-check >}}
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If you are running a different version of Kubernetes, check the documentation for that release.
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-->
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* 你需要运行提供此特性的 Kubernetes 版本。
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Kubernetes 1.27 提供了对基于事件更新容器状态的 Beta 支持。
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此特性处于 Beta 阶段，默认被**禁用**。
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* {{< version-check >}}
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如果你正在运行不同版本的 Kubernetes，请查阅对应版本的文档。
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<!--
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* The container runtime in use must support container lifecycle events.
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The kubelet automatically switches back to the legacy generic PLEG
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mechanism if the container runtime does not announce support for
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container lifecycle events, even if you have this feature gate enabled.
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-->
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* 所使用的容器运行时必须支持容器生命周期事件。
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如果容器运行时未声明对容器生命周期事件的支持，即使你已启用了此特性门控，
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kubelet 也会自动切换回传统的通用 PLEG。
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<!-- steps -->
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<!--
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## Why switch to Evented PLEG?
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* The _Generic PLEG_ incurs non-negligible overhead due to frequent polling of container statuses.
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* This overhead is exacerbated by kubelet's parallelized polling of container states, thus limiting
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its scalability and causing poor performance and reliability problems.
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* The goal of _Evented PLEG_ is to reduce unnecessary work during inactivity
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by replacing periodic polling.
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-->
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## 为什么要切换到事件驱动的 PLEG？ {#why-switch-to-evented-pleg}
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* **通用 PLEG** 由于频繁轮询容器状态而产生了不可忽略的开销。
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* 这种开销会被 kubelet 的并行轮询容器状态的机制加剧，
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限制了可扩缩性，还会导致性能和可靠性问题。
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* **事件驱动的 PLEG** 的目标是通过替换定期轮询来减少闲置时的非必要任务。
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<!--
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## Switching to Evented PLEG
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1. Start the kubelet with the [feature gate](/docs/reference/command-line-tools-reference/feature-gates/)
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`EventedPLEG` enabled. You can manage the kubelet feature gates editing the kubelet
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[config file](/docs/tasks/administer-cluster/kubelet-config-file/) and restarting the kubelet service.
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You need to do this on each node where you are using this feature.
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-->
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## 切换为事件驱动的 PLEG {#switching-to-evented-pleg}
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1. 启用[特性门控](/zh-cn/docs/reference/command-line-tools-reference/feature-gates/)
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`EventedPLEG` 后启动 kubelet。
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你可以通过编辑 kubelet [配置文件](/zh-cn/docs/tasks/administer-cluster/kubelet-config-file/)并重启
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kubelet 服务来管理 kubelet 特性门控。
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你需要在使用此特性的所有节点上执行此操作。
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<!--
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2. Make sure the node is [drained](/docs/tasks/administer-cluster/safely-drain-node/) before proceeding.
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3. Start the container runtime with the container event generation enabled.
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-->
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2. 确保节点被[腾空](/zh-cn/docs/tasks/administer-cluster/safely-drain-node/)后再继续。
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3. 启用容器事件生成后启动容器运行时。
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{{< tabs name="tab_with_code" >}}
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{{% tab name="containerd" %}}
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<!--
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Version 1.7+
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-->
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版本 1.7+
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{{% /tab %}}
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{{% tab name="CRI-O" %}}
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<!--
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Version 1.26+
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Check if the CRI-O is already configured to emit CRI events by verifying the configuration,
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-->
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版本 1.26+
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通过验证配置，检查 CRI-O 是否已配置为发送 CRI 事件：
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```shell
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crio config | grep enable_pod_events
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```
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<!--
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If it is enabled, the output should be similar to the following:
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-->
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如果已启用，输出应类似于：
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```none
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enable_pod_events = true
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```
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<!--
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To enable it, start the CRI-O daemon with the flag `--enable-pod-events=true` or
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use a dropin config with the following lines:
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-->
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要启用它，可使用 `--enable-pod-events=true` 标志或添加以下配置来启动 CRI-O 守护进程：
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```toml
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[crio.runtime]
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enable_pod_events: true
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```
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{{% /tab %}}
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{{< /tabs >}}
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{{< version-check >}}
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<!--
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4. Verify that the kubelet is using event-based container stage change monitoring.
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To check, look for the term `EventedPLEG` in the kubelet logs.
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The output should be similar to this:
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-->
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4. 确认 kubelet 正使用基于事件的容器阶段变更监控。
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要检查这一点，可在 kubelet 日志中查找 `EventedPLEG` 词条。
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输出类似于：
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```console
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I0314 11:10:13.909915 1105457 feature_gate.go:249] feature gates: &{map[EventedPLEG:true]}
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```
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<!--
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If you have set `--v` to 4 and above, you might see more entries that indicate
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that the kubelet is using event-based container state monitoring.
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-->
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如果你将 `--v` 设置为 4 及更高值，你可能会看到更多条目表明
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kubelet 正在使用基于事件的容器状态监控。
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```console
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I0314 11:12:42.009542 1110177 evented.go:238] "Evented PLEG: Generated pod status from the received event" podUID=3b2c6172-b112-447a-ba96-94e7022912dc
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I0314 11:12:44.623326 1110177 evented.go:238] "Evented PLEG: Generated pod status from the received event" podUID=b3fba5ea-a8c5-4b76-8f43-481e17e8ec40
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I0314 11:12:44.714564 1110177 evented.go:238] "Evented PLEG: Generated pod status from the received event" podUID=b3fba5ea-a8c5-4b76-8f43-481e17e8ec40
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```
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## {{% heading "whatsnext" %}}
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<!--
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* Learn more about the design in the Kubernetes Enhancement Proposal (KEP):
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[kubelet Evented PLEG for Better Performance](https://github.com/kubernetes/enhancements/blob/5b258a990adabc2ffdc9d84581ea6ed696f7ce6c/keps/sig-node/3386-kubelet-evented-pleg/README.md).
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-->
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* 进一步了解 Kubernetes 增强提案 (KEP)：
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[kubelet Evented PLEG for Better Performance](https://github.com/kubernetes/enhancements/blob/5b258a990adabc2ffdc9d84581ea6ed696f7ce6c/keps/sig-node/3386-kubelet-evented-pleg/README.md)
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中的设计理念。
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