189 lines
8.9 KiB
Markdown
189 lines
8.9 KiB
Markdown
---
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layout: blog
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title: "Kubernetes v1.33：Job 逐索引的回退限制进阶至 GA"
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date: 2025-05-13T10:30:00-08:00
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slug: kubernetes-v1-33-jobs-backoff-limit-per-index-goes-ga
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author: >
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[Michał Woźniak](https://github.com/mimowo) (Google)
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translator: >
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[Michael Yao](https://github.com/windsonsea) (DaoCloud)
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---
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<!--
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layout: blog
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title: "Kubernetes v1.33: Job's Backoff Limit Per Index Goes GA"
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date: 2025-05-13T10:30:00-08:00
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slug: kubernetes-v1-33-jobs-backoff-limit-per-index-goes-ga
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author: >
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[Michał Woźniak](https://github.com/mimowo) (Google)
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-->
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<!--
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In Kubernetes v1.33, the _Backoff Limit Per Index_ feature reaches general
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availability (GA). This blog describes the Backoff Limit Per Index feature and
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its benefits.
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-->
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在 Kubernetes v1.33 中，**逐索引的回退限制**特性进阶至 GA（正式发布）。本文介绍此特性及其优势。
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<!--
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## About backoff limit per index
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When you run workloads on Kubernetes, you must consider scenarios where Pod
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failures can affect the completion of your workloads. Ideally, your workload
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should tolerate transient failures and continue running.
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To achieve failure tolerance in a Kubernetes Job, you can set the
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`spec.backoffLimit` field. This field specifies the total number of tolerated
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failures.
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-->
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## 关于逐索引的回退限制 {#about-backoff-limit-per-index}
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当你在 Kubernetes 上运行工作负载时，必须考虑 Pod 失效可能影响工作负载完成的场景。
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理想情况下，你的工作负载应该能够容忍短暂的失效并继续运行。
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为了在 Kubernetes Job 中容忍失效，你可以设置 `spec.backoffLimit` 字段。
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此字段指定容忍的失效总数。
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<!--
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However, for workloads where every index is considered independent, like
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[embarassingly parallel](https://en.wikipedia.org/wiki/Embarrassingly_parallel)
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workloads - the `spec.backoffLimit` field is often not flexible enough.
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For example, you may choose to run multiple suites of integration tests by
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representing each suite as an index within an [Indexed Job](/docs/tasks/job/indexed-parallel-processing-static/).
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In that setup, a fast-failing index (test suite) is likely to consume your
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entire budget for tolerating Pod failures, and you might not be able to run the
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other indexes.
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-->
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但是，对于每个索引都被视为独立单元的工作负载，
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比如[过易并行](https://zh.wikipedia.org/zh-cn/%E8%BF%87%E6%98%93%E5%B9%B6%E8%A1%8C)的工作负载，
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`spec.backoffLimit` 字段通常不够灵活。例如，你可以选择运行多个继承测试套件，
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将每个套件作为[带索引的 Job](/zh-cn/docs/tasks/job/indexed-parallel-processing-static/)内的某个索引。
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在这种情况下，快速失效的索引（测试套件）很可能消耗你全部的 Pod 失效容忍预算，你可能无法运行其他索引的 Pod。
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<!--
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In order to address this limitation, Kubernetes introduced _backoff limit per index_,
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which allows you to control the number of retries per index.
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## How backoff limit per index works
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To use Backoff Limit Per Index for Indexed Jobs, specify the number of tolerated
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Pod failures per index with the `spec.backoffLimitPerIndex` field. When you set
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this field, the Job executes all indexes by default.
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-->
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为了解决这一限制，Kubernetes 引入了**逐索引的回退限制**，允许你控制逐索引的重试次数。
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## 逐索引回退限制的工作原理 {#how-backoff-limit-per-index-works}
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要在带索引的 Job 中使用逐索引的回退限制，可以通过 `spec.backoffLimitPerIndex`
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字段指定每个索引允许的 Pod 失效次数。当你设置此字段后，Job 默认将执行所有索引。
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<!--
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Additionally, to fine-tune the error handling:
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* Specify the cap on the total number of failed indexes by setting the
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`spec.maxFailedIndexes` field. When the limit is exceeded the entire Job is
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terminated.
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* Define a short-circuit to detect a failed index by using the `FailIndex` action in the
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[Pod Failure Policy](/docs/concepts/workloads/controllers/job/#pod-failure-policy)
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mechanism.
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-->
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另外，你可以通过以下方式微调错误处理：
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* 通过设置 `spec.maxFailedIndexes` 字段，指定失效索引总数的上限。超过此限制时，整个 Job 会被终止。
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* 通过 [Pod 失效策略](/zh-cn/docs/concepts/workloads/controllers/job/#pod-failure-policy)机制中的
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`FailIndex` 动作定义短路来检测失效的索引。
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<!--
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When the number of tolerated failures is exceeded, the Job marks that index as
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failed and lists it in the Job's `status.failedIndexes` field.
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### Example
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The following Job spec snippet is an example of how to combine backoff limit per
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index with the _Pod Failure Policy_ feature:
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-->
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当超过容忍的失效次数时，Job 会将该索引标记为失效，并在 Job 的 `status.failedIndexes` 字段中列出该索引。
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### 示例
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下面的 Job 规约片段展示了如何将逐索引的回退限制与 **Pod 失效策略**特性结合使用：
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```yaml
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completions: 10
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parallelism: 10
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completionMode: Indexed
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backoffLimitPerIndex: 1
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maxFailedIndexes: 5
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podFailurePolicy:
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rules:
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- action: Ignore
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onPodConditions:
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- type: DisruptionTarget
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- action: FailIndex
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onExitCodes:
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operator: In
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values: [ 42 ]
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```
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<!--
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In this example, the Job handles Pod failures as follows:
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- Ignores any failed Pods that have the built-in
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[disruption condition](/docs/concepts/workloads/pods/disruptions/#pod-disruption-conditions),
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called `DisruptionTarget`. These Pods don't count towards Job backoff limits.
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- Fails the index corresponding to the failed Pod if any of the failed Pod's
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containers finished with the exit code 42 - based on the matching "FailIndex"
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rule.
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-->
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在此例中，Job 对 Pod 失效的处理逻辑如下：
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* 忽略具有内置[干扰状况](/zh-cn/docs/concepts/workloads/pods/disruptions/#pod-disruption-conditions)
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（称为 `DisruptionTarget`）的失效 Pod。这些 Pod 不计入 Job 的回退限制。
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* 如果失效的 Pod 中任何容器的退出码是 42，则基于匹配的 `FailIndex` 规则，将对应的索引标记为失效。
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<!--
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- Retries the first failure of any index, unless the index failed due to the
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matching `FailIndex` rule.
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- Fails the entire Job if the number of failed indexes exceeded 5 (set by the
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`spec.maxFailedIndexes` field).
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-->
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* 除非索引因匹配的 `FailIndex` 规则失效，否则会重试该索引的首次失效。
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* 如果失效索引数量超过 5 个（由 `spec.maxFailedIndexes` 设置），则整个 Job 失效。
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<!--
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## Learn more
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- Read the blog post on the closely related feature of Pod Failure Policy [Kubernetes 1.31: Pod Failure Policy for Jobs Goes GA](/blog/2024/08/19/kubernetes-1-31-pod-failure-policy-for-jobs-goes-ga/)
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- For a hands-on guide to using Pod failure policy, including the use of FailIndex, see
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[Handling retriable and non-retriable pod failures with Pod failure policy](/docs/tasks/job/pod-failure-policy/)
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- Read the documentation for
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[Backoff limit per index](/docs/concepts/workloads/controllers/job/#backoff-limit-per-index) and
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[Pod failure policy](/docs/concepts/workloads/controllers/job/#pod-failure-policy)
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- Read the KEP for the [Backoff Limits Per Index For Indexed Jobs](https://github.com/kubernetes/enhancements/tree/master/keps/sig-apps/3850-backoff-limits-per-index-for-indexed-jobs)
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-->
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## 进一步了解
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* 阅读与 Pod 失效策略密切相关的博客文章：[Kubernetes 1.31：Job 的 Pod 失效策略进阶至 GA](/zh-cn/blog/2024/08/19/kubernetes-1-31-pod-failure-policy-for-jobs-goes-ga/)
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* 查看包含 FailIndex 用法在内的 Pod 失效策略实操指南：
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[使用 Pod 失效策略处理可重试和不可重试的 Pod 失效](/zh-cn/docs/tasks/job/pod-failure-policy/)
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* 阅读[逐索引的回退限制](/zh-cn/docs/concepts/workloads/controllers/job/#backoff-limit-per-index)和
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[Pod 失效策略](/zh-cn/docs/concepts/workloads/controllers/job/#pod-failure-policy)等文档
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* 查阅 KEP：[带索引的 Job 的逐索引回退限制](https://github.com/kubernetes/enhancements/tree/master/keps/sig-apps/3850-backoff-limits-per-index-for-indexed-jobs)
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<!--
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## Get involved
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This work was sponsored by the Kubernetes
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[batch working group](https://github.com/kubernetes/community/tree/master/wg-batch)
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in close collaboration with the
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[SIG Apps](https://github.com/kubernetes/community/tree/master/sig-apps) community.
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If you are interested in working on new features in the space we recommend
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subscribing to our [Slack](https://kubernetes.slack.com/messages/wg-batch)
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channel and attending the regular community meetings.
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-->
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## 参与此工作 {#get-involved}
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这项工作由 Kubernetes [Batch Working Group（批处理工作组）](https://github.com/kubernetes/community/tree/master/wg-batch)负责，且与
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[SIG Apps](https://github.com/kubernetes/community/tree/master/sig-apps) 社区密切协作。
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如果你有兴趣参与此领域的新特性开发，建议订阅我们的
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[Slack 频道](https://kubernetes.slack.com/messages/wg-batch)，并参加定期社区会议。
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