RocMarshal opened a new pull request, #27189:
URL: https://github.com/apache/flink/pull/27189
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## Contribution Checklist
- Make sure that the pull request corresponds to a [JIRA
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## What is the purpose of the change
Enhance the requests and slots balanced allocation logic in DefaultScheduler
```
This patch is designed to handle the pre-matching of resource requests in
the context of balanced task scheduling for streaming jobs. During the batch
allocation of resources, where resource requests are allocated in a single,
non-interleaved operation, it is impossible to make immediate individual
adjustments to unmatched resource requests. This may lead to situations where
not all resource requests can be successfully fulfilled. For example:
resource requests:
- resource request-1: ResourceProfile-1(UNKNOWN)
- resource request-2: ResourceProfile-2(cpu=2 core, memory=2G)
available slots:
- slot-a: ResourceProfile-a(cpu=1 core, memory=1G)
- slot-b: ResourceProfile-b(cpu=2 core, memory=2G)
When the strategy TasksBalancedRequestSlotMatchingStrategy performs resource
allocation, the following matching mapping might occur, preventing all slot
requests from being successfully assigned in a consistent manner and thus
hindering the scheduling of the entire job:
the unexpected mapping case:
- resource request-1: ResourceProfile-1(UNKNOWN) was matched with
slot-b: ResourceProfile-b(cpu=2 core, memory=2G)
- resource request-2: ResourceProfile-2(cpu=2 core, memory=2G) was not
matched
Therefore, it is crucial to determine how ResourceProfiles should match
before the batch allocation of resource requests, aiming to assure the
allocation successfully at least. An ideal matching relationship would be:
- ResourceProfile-1(UNKNOWN) -> ResourceProfile-a(cpu=1
core, memory=1G)
- ResourceProfile-2(cpu=2 core, memory=2G) -> ResourceProfile-b(cpu=2
core, memory=2G)
This is the motivation for introducing the current patch.
```
## Brief change log
- Introduce ResourceRequestPreMappings to compute the resource matching
relationships when allocating all slots in bulk for balanced scheduling of
streaming jobs in the default scheduler.
- Introduce the test cases for ResourceRequestPreMappings.
- Adapt the calculation logic of the
TasksBalancedRequestSlotMatchingStrategy for bulk slot allocation using
ResourceRequestPreMappings, in order to prevent job scheduling timeouts caused
by untimely updates to the relationships between all requests and resources in
load-balancing scenarios
- Introduce TasksBalancedRequestSlotMatchingStrategyTest for enhancing the
TasksBalancedRequestSlotMatchingStrategy testing.
## Verifying this change
This change added tests and can be verified as follows:
- org.apache.flink.runtime.jobmaster.slotpool.ResourceRequestPreMappingsTest
-
org.apache.flink.runtime.jobmaster.slotpool.TasksBalancedRequestSlotMatchingStrategyTest
-
org.apache.flink.runtime.jobmaster.slotpool.PreferredAllocationRequestSlotMatchingStrategyTest
## Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): (yes / **no**)
- The public API, i.e., is any changed class annotated with
`@Public(Evolving)`: (yes / **no**)
- The serializers: (yes / **no** / don't know)
- The runtime per-record code paths (performance sensitive): (yes / **no**
/ don't know)
- Anything that affects **deployment** : default scheduler balanced tasks
scheduling.
- The S3 file system connector: (yes / **no** / don't know)
## Documentation
- Does this pull request introduce a new feature? (yes / **no**)
- If yes, how is the feature documented? (**not applicable** / docs /
JavaDocs / not documented)
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