YongGang opened a new pull request, #14880:
URL: https://github.com/apache/druid/pull/14880
### Description
During testing of the K8s task runner, peon pods faced challenges in
achieving a graceful termination upon receiving a SIGTERM signal. Typically,
they would encounter an `InterruptedException` and subsequently fail to push
their `status.json`. As a result, the Druid console would display a vague "task
status not found" message. Such graceful terminations may arise when a pod is
manually deleted by K8s or is terminated due to out-of-memory conditions.
The primary issues behind this behavior are:
1. When attempting to halt a task, the thread is interrupted. This
interruption inadvertently prevents the completion of the task `cleanUp`
operation.
2. The task relies on services like `DiscoveryServiceLocator` and
`OverlordClient` to execute its cleanUp work. However, since they all exist
within the same lifecycle scope (NORMAL scope), there's a risk that the
dependent services might be stopped before the task's `cleanUp` process
concludes. To rectify this, we've transitioned the `SingleTaskBackgroundRunner`
to the SERVER scope, ensuring the task stops prior to its dependent services,
allowing for a successful cleanUp.
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#### Release note
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Fix Peon not fail gracefully.
<hr>
##### Key changed/added classes in this PR
* In `AbstractTask` add `cleanupCompletionLatch`
* In `SingleTaskBackgroundRunner` wait for the latch to finish when
stopping.
* In `CliPeon` move `SingleTaskBackgroundRunner` to the SERVER scope.
<hr>
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This PR has:
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- [ ] using the [concurrency
checklist](https://github.com/apache/druid/blob/master/dev/code-review/concurrency.md)
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- [ ] added documentation for new or modified features or behaviors.
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- [ ] added or updated version, license, or notice information in
[licenses.yaml](https://github.com/apache/druid/blob/master/dev/license.md)
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- [ ] added unit tests or modified existing tests to cover new code paths,
ensuring the threshold for [code
coverage](https://github.com/apache/druid/blob/master/dev/code-review/code-coverage.md)
is met.
- [ ] added integration tests.
- [x] been tested in a test Druid cluster.
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