[zh] sync ttlafterfinished.md

Author: windsonsea

content/zh-cn/docs/concepts/workloads/controllers/ttlafterfinished.md

@@ -2,113 +2,141 @@
 title: 已完成 Job 的自动清理
 content_type: concept
 weight: 70
+description: >-
+  一种用于清理已完成执行的旧 Job 的 TTL 机制。
 ---
 <!--
-title: Automatic Clean-up for Finished Jobs
+reviewers:
+- janetkuo
+title: Automatic Cleanup for Finished Jobs
 content_type: concept
 weight: 70
+description: >-
+  A time-to-live mechanism to clean up old Jobs that have finished execution.
 -->
 
 <!-- overview -->
 
 {{< feature-state for_k8s_version="v1.23" state="stable" >}}
 
 <!--
-TTL-after-finished {{<glossary_tooltip text="controller" term_id="controller">}} provides a 
-TTL (time to live) mechanism to limit the lifetime of resource objects that 
-have finished execution. TTL controller only handles 
-{{< glossary_tooltip text="Jobs" term_id="job" >}}.
+When your Job has finished, it's useful to keep that Job in the API (and not immediately delete the Job)
+so that you can tell whether the Job succeeded or failed.
+
+Kubernetes' TTL-after-finished {{<glossary_tooltip text="controller" term_id="controller">}} provides a
+TTL (time to live) mechanism to limit the lifetime of Job objects that
+have finished execution.
 -->
-TTL-after-finished {{<glossary_tooltip text="控制器" term_id="controller">}} 提供了一种 TTL 机制来限制已完成执行的资源对象的生命周期。
-TTL 控制器目前只处理 {{< glossary_tooltip text="Job" term_id="job" >}}。
+当你的 Job 已结束时，将 Job 保留在 API 中（而不是立即删除 Job）很有用，
+这样你就可以判断 Job 是成功还是失败。
 
+Kubernetes TTL-after-finished {{<glossary_tooltip text="控制器" term_id="controller">}}提供了一种
+TTL 机制来限制已完成执行的 Job 对象的生命期。
 
 <!-- body -->
 
 <!--
-## TTL-after-finished Controller
+## Cleanup for finished Jobs
 
-The TTL-after-finished controller is only supported for Jobs. A cluster operator can use this feature to clean
+The TTL-after-finished controller is only supported for Jobs. You can use this mechanism to clean
 up finished Jobs (either `Complete` or `Failed`) automatically by specifying the
 `.spec.ttlSecondsAfterFinished` field of a Job, as in this
 [example](/docs/concepts/workloads/controllers/job/#clean-up-finished-jobs-automatically).
 -->
-## TTL-after-finished 控制器
+## 清理已完成的 Job   {#cleanup-for-finished-jobs}
 
-TTL-after-finished 控制器只支持 Job。集群操作员可以通过指定 Job 的 `.spec.ttlSecondsAfterFinished`
-字段来自动清理已结束的作业（`Complete` 或 `Failed`），如
-[示例](/zh-cn/docs/concepts/workloads/controllers/job/#clean-up-finished-jobs-automatically)
-所示。
+TTL-after-finished 控制器只支持 Job。你可以通过指定 Job 的 `.spec.ttlSecondsAfterFinished`
+字段来自动清理已结束的 Job（`Complete` 或 `Failed`），
+如[示例](/zh-cn/docs/concepts/workloads/controllers/job/#clean-up-finished-jobs-automatically)所示。
 
 <!--
-The TTL-after-finished controller will assume that a job is eligible to be cleaned up
-TTL seconds after the job has finished, in other words, when the TTL has expired. When the
+The TTL-after-finished controller assumes that a Job is eligible to be cleaned up
+TTL seconds after the Job has finished. The timer starts once the
+status condition of the Job changes to show that the Job is either `Complete` or `Failed`; once the TTL has
+expired, that Job becomes eligible for
+[cascading](/docs/concepts/architecture/garbage-collection/#cascading-deletion) removal. When the
 TTL-after-finished controller cleans up a job, it will delete it cascadingly, that is to say it will delete
-its dependent objects together with it. Note that when the job is deleted,
-its lifecycle guarantees, such as finalizers, will be honored.
+its dependent objects together with it.
 -->
-TTL-after-finished 控制器假设作业能在执行完成后的 TTL 秒内被清理，也就是当 TTL 过期后。
-当 TTL 控制器清理作业时，它将做级联删除操作，即删除资源对象的同时也删除其依赖对象。
-注意，当资源被删除时，由该资源的生命周期保证其终结器（Finalizers）等被执行。
+TTL-after-finished 控制器假设 Job 能在执行完成后的 TTL 秒内被清理。一旦 Job
+的状态条件发生变化表明该 Job 是 `Complete` 或 `Failed`，计时器就会启动；一旦 TTL 已过期，该 Job
+就能被[级联删除](/zh-cn/docs/concepts/architecture/garbage-collection/#cascading-deletion)。
+当 TTL 控制器清理作业时，它将做级联删除操作，即删除 Job 的同时也删除其依赖对象。
 
 <!--
-The TTL seconds can be set at any time. Here are some examples for setting the
+Kubernetes honors object lifecycle guarantees on the Job, such as waiting for
+[finalizers](/docs/concepts/overview/working-with-objects/finalizers/).
+
+You can set the TTL seconds at any time. Here are some examples for setting the
 `.spec.ttlSecondsAfterFinished` field of a Job:
 -->
-可以随时设置 TTL 秒。以下是设置 Job 的 `.spec.ttlSecondsAfterFinished` 字段的一些示例：
+Kubernetes 尊重 Job 对象的生命周期保证，例如等待
+[Finalizer](/zh-cn/docs/concepts/overview/working-with-objects/finalizers/)。
+
+你可以随时设置 TTL 秒。以下是设置 Job 的 `.spec.ttlSecondsAfterFinished` 字段的一些示例：
 
 <!--
-* Specify this field in the job manifest, so that a Job can be cleaned up
+* Specify this field in the Job manifest, so that a Job can be cleaned up
   automatically some time after it finishes.
-* Set this field of existing, already finished jobs, to adopt this new feature.
+* Manually set this field of existing, already finished Jobs, so that they become eligible
+  for cleanup.
 * Use a
   [mutating admission webhook](/docs/reference/access-authn-authz/extensible-admission-controllers/#admission-webhooks)
-  to set this field dynamically at job creation time. Cluster administrators can
+  to set this field dynamically at Job creation time. Cluster administrators can
   use this to enforce a TTL policy for finished jobs.
+-->
+* 在 Job 清单（manifest）中指定此字段，以便 Job 在完成后的某个时间被自动清理。
+* 手动设置现有的、已完成的 Job 的此字段，以便这些 Job 可被清理。
+* 在创建 Job 时使用[修改性质的准入 Webhook](/zh-cn/docs/reference/access-authn-authz/extensible-admission-controllers/#admission-webhooks)
+  动态设置该字段。集群管理员可以使用它对已完成的作业强制执行 TTL 策略。
+<!--
 * Use a
   [mutating admission webhook](/docs/reference/access-authn-authz/extensible-admission-controllers/#admission-webhooks)
-  to set this field dynamically after the job has finished, and choose
-  different TTL values based on job status, labels, etc.
+  to set this field dynamically after the Job has finished, and choose
+  different TTL values based on job status, labels. For this case, the webhook needs
+  to detect changes to the `.status` of the Job and only set a TTL when the Job
+  is being marked as completed.
+* Write your own controller to manage the cleanup TTL for Jobs that match a particular
+  {{< glossary_tooltip term_id="selector" text="selector-selector" >}}.
 -->
-* 在作业清单（manifest）中指定此字段，以便 Job 在完成后的某个时间被自动清除。
-* 将此字段设置为现有的、已完成的作业，以采用此新功能。
-* 在创建作业时使用 [mutating admission webhook](/zh-cn/docs/reference/access-authn-authz/extensible-admission-controllers/#admission-webhooks)
-  动态设置该字段。集群管理员可以使用它对完成的作业强制执行 TTL 策略。
-* 使用 [mutating admission webhook](/zh-cn/docs/reference/access-authn-authz/extensible-admission-controllers/#admission-webhooks)
-  在作业完成后动态设置该字段，并根据作业状态、标签等选择不同的 TTL 值。
+* 使用[修改性质的准入 Webhook](/zh-cn/docs/reference/access-authn-authz/extensible-admission-controllers/#admission-webhooks)
+  在 Job 完成后动态设置该字段，并根据 Job 状态、标签等选择不同的 TTL 值。
+  对于这种情况，Webhook 需要检测 Job 的 `.status` 变化，并且仅在 Job 被标记为已完成时设置 TTL。
+* 编写你自己的控制器来管理与特定{{< glossary_tooltip term_id="selector" text="选择算符" >}}匹配的
+  Job 的清理 TTL。
 
 <!--
-## Caveat
+## Caveats
 
-### Updating TTL Seconds
+### Updating TTL for finished Jobs
 
-Note that the TTL period, e.g. `.spec.ttlSecondsAfterFinished` field of Jobs,
-can be modified after the job is created or has finished. However, once the
-Job becomes eligible to be deleted (when the TTL has expired), the system won't
-guarantee that the Jobs will be kept, even if an update to extend the TTL
-returns a successful API response.
+You can modify the TTL period, e.g. `.spec.ttlSecondsAfterFinished` field of Jobs,
+after the job is created or has finished. If you extend the TTL period after the
+existing `ttlSecondsAfterFinished` period has expired, Kubernetes doesn't guarantee
+to retain that Job, even if an update to extend the TTL returns a successful API
+response.
 -->
-## 警告
+## 警告  {#caveats}
 
-### 更新 TTL 秒数
+### 更新已完成 Job 的 TTL  {#updating-ttl-for-finished-jobs}
 
-请注意，在创建 Job 或已经执行结束后，仍可以修改其 TTL 周期，例如 Job 的
+在创建 Job 或已经执行结束后，你仍可以修改其 TTL 周期，例如 Job 的
 `.spec.ttlSecondsAfterFinished` 字段。
-但是一旦 Job 变为可被删除状态（当其 TTL 已过期时），即使你通过 API 增加其 TTL
-时长得到了成功的响应，系统也不保证 Job 将被保留。
+如果你在当前 `ttlSecondsAfterFinished` 时长已过期后延长 TTL 周期，
+即使延长 TTL 的更新得到了成功的 API 响应，Kubernetes 也不保证保留此 Job，
 
 <!--
-### Time Skew
+### Time skew
 
-Because TTL-after-finished controller uses timestamps stored in the Kubernetes resources to
+Because the TTL-after-finished controller uses timestamps stored in the Kubernetes jobs to
 determine whether the TTL has expired or not, this feature is sensitive to time
-skew in the cluster, which may cause TTL-after-finished controller to clean up resource objects
+skew in your cluster, which may cause the control plane to clean up Job objects
 at the wrong time.
 -->
 ### 时间偏差  {#time-skew}
 
-由于 TTL-after-finished 控制器使用存储在 Kubernetes 资源中的时间戳来确定 TTL 是否已过期，
-因此该功能对集群中的时间偏差很敏感，这可能导致 TTL-after-finished 控制器在错误的时间清理资源对象。
+由于 TTL-after-finished 控制器使用存储在 Kubernetes Job 中的时间戳来确定 TTL 是否已过期，
+因此该功能对集群中的时间偏差很敏感，这可能导致控制平面在错误的时间清理 Job 对象。
 
 <!--
 Clocks aren't always correct, but the difference should be
@@ -120,9 +148,13 @@ very small. Please be aware of this risk when setting a non-zero TTL.
 ## {{% heading "whatsnext" %}}
 
 <!--
-* [Clean up Jobs automatically](/docs/concepts/workloads/controllers/jobs-run-to-completion/#clean-up-finished-jobs-automatically)
-* [Design doc](https://github.com/kubernetes/enhancements/blob/master/keps/sig-apps/592-ttl-after-finish/README.md)
+* Read [Clean up Jobs automatically](/docs/concepts/workloads/controllers/job/#clean-up-finished-jobs-automatically)
+
+* Refer to the [Kubernetes Enhancement Proposal](https://github.com/kubernetes/enhancements/blob/master/keps/sig-apps/592-ttl-after-finish/README.md)
+  (KEP) for adding this mechanism.
 -->
-* [自动清理 Job](/zh-cn/docs/concepts/workloads/controllers/job/#clean-up-finished-jobs-automatically)
-* [设计文档](https://github.com/kubernetes/enhancements/blob/master/keps/sig-apps/592-ttl-after-finish/README.md)
+* 阅读[自动清理 Job](/zh-cn/docs/concepts/workloads/controllers/job/#clean-up-finished-jobs-automatically)
+
+* 参阅 [Kubernetes 增强提案](https://github.com/kubernetes/enhancements/blob/master/keps/sig-apps/592-ttl-after-finish/README.md)
+  (KEP) 了解此机制的演进过程。