Qiming Teng
c52818c03d
This is the first step to rename 'zh' to 'zh-cn'. There are several reasons why we rename the language name.
- The upstream docsy theme changed the language name, leading to many warnings during site build;
The side-effect is that the i18n strings are no longer working.
- We believe renaming the language is the right thing to do, because this move can make room for other variants of Chinese language, such as 'zh-tw', 'zh-sg' etc.
There would be several follow-ups to this PR, such as fixing the intra-site links, adding redirects etc.
We will lock up changes to zh/zh-cn pages for the moment, until this one gets in.
This PR is based on commit cdad0a7342.
43 lines
2.4 KiB
Markdown
43 lines
2.4 KiB
Markdown
---
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title: 关键插件 Pod 的调度保证
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content_type: concept
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---
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<!-- overview -->
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<!--
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Kubernetes core components such as the API server, scheduler, and controller-manager run on a control plane node.
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However, add-ons must run on a regular cluster node.
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Some of these add-ons are critical to a fully functional cluster, such as metrics-server, DNS, and UI.
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A cluster may stop working properly if a critical add-on is evicted (either manually or as a side effect of another operation like upgrade)
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and becomes pending (for example when the cluster is highly utilized and either there are other pending pods that schedule into the space
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vacated by the evicted critical add-on pod or the amount of resources available on the node changed for some other reason).
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-->
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Kubernetes 核心组件（如 API 服务器、调度器、控制器管理器）在控制平面节点上运行。
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但是插件必须在常规集群节点上运行。
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其中一些插件对于功能完备的集群至关重要，例如 Heapster、DNS 和 UI。
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如果关键插件被逐出（手动或作为升级等其他操作的副作用）或者变成挂起状态，集群可能会停止正常工作。
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关键插件进入挂起状态的例子有：集群利用率过高；被逐出的关键插件 Pod 释放了空间，但该空间被之前悬决的 Pod 占用；由于其它原因导致节点上可用资源的总量发生变化。
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<!--
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Note that marking a pod as critical is not meant to prevent evictions entirely; it only prevents the pod from becoming permanently unavailable.
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A static pod marked as critical, can't be evicted. However, a non-static pods marked as critical are always rescheduled.
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-->
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注意，把某个 Pod 标记为关键 Pod 并不意味着完全避免该 Pod 被逐出；它只能防止该 Pod 变成永久不可用。
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被标记为关键性的静态 Pod 不会被逐出。但是，被标记为关键性的非静态 Pod 总是会被重新调度。
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<!-- body -->
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<!--
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### Marking pod as critical
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-->
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### 标记关键 Pod
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<!--
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To mark a Pod as critical, set priorityClassName for that Pod to `system-cluster-critical` or `system-node-critical`. `system-node-critical` is the highest available priority, even higher than `system-cluster-critical`
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-->
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要将 Pod 标记为关键性（critical），设置 Pod 的 priorityClassName 为 `system-cluster-critical` 或者 `system-node-critical`。
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`system-node-critical` 是最高级别的可用性优先级，甚至比 `system-cluster-critical` 更高。
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