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https://issues.apache.org/jira/browse/SPARK-12554?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Lijie Xu updated SPARK-12554:
-----------------------------
Description:
In scheduleExecutorsOnWorker() in Master.scala,
{{val keepScheduling = coresToAssign >= minCoresPerExecutor}} should be changed
to {{val keepScheduling = coresToAssign > 0}}
Case 1:
Suppose that an app's requested cores is 10 (i.e., {{spark.cores.max = 10}})
and app.coresPerExecutor is 4 (i.e., {{spark.executor.cores = 4}}).
After allocating two executors (each has 4 cores) to this app, the
{{app.coresToAssign = 2}} and {{minCoresPerExecutor = coresPerExecutor = 4}},
so {{keepScheduling = false}} and no extra executor will be allocated to this
app. If {{spark.scheduler.minRegisteredResourcesRatio}} is set to a large
number (e.g., > 0.8 in this case), the app will hang and never finish.
Case 2: if a small app's coresPerExecutor is larger than its requested cores
(e.g., {{spark.cores.max = 10}}, {{spark.executor.cores = 16}}), {{val
keepScheduling = coresToAssign >= minCoresPerExecutor}} is always FALSE. As a
result, this app will never get an executor to run.
was:
In scheduleExecutorsOnWorker() in Master.scala,
*val keepScheduling = coresToAssign >= minCoresPerExecutor* should be changed
to *val keepScheduling = coresToAssign > 0*
Case 1:
Suppose that an app's requested cores is 10 (i.e., spark.cores.max = 10) and
app.coresPerExecutor is 4 (i.e., spark.executor.cores = 4).
After allocating two executors (each has 4 cores) to this app, the
*app.coresToAssign = 2* and *minCoresPerExecutor = coresPerExecutor = 4*, so
*keepScheduling = false* and no extra executor will be allocated to this app.
If *spark.scheduler.minRegisteredResourcesRatio* is set to a large number
(e.g., > 0.8 in this case), the app will hang and never finish.
Case 2: if a small app's coresPerExecutor is larger than its requested cores
(e.g., spark.cores.max = 10, spark.executor.cores = 16), *val keepScheduling =
coresToAssign >= minCoresPerExecutor* is always FALSE. As a result, this app
will never get an executor to run.
> Standalone app scheduler will hang when app.coreToAssign < minCoresPerExecutor
> ------------------------------------------------------------------------------
>
> Key: SPARK-12554
> URL: https://issues.apache.org/jira/browse/SPARK-12554
> Project: Spark
> Issue Type: Bug
> Components: Deploy, Scheduler
> Affects Versions: 1.5.2
> Reporter: Lijie Xu
>
> In scheduleExecutorsOnWorker() in Master.scala,
> {{val keepScheduling = coresToAssign >= minCoresPerExecutor}} should be
> changed to {{val keepScheduling = coresToAssign > 0}}
> Case 1:
> Suppose that an app's requested cores is 10 (i.e., {{spark.cores.max = 10}})
> and app.coresPerExecutor is 4 (i.e., {{spark.executor.cores = 4}}).
> After allocating two executors (each has 4 cores) to this app, the
> {{app.coresToAssign = 2}} and {{minCoresPerExecutor = coresPerExecutor = 4}},
> so {{keepScheduling = false}} and no extra executor will be allocated to this
> app. If {{spark.scheduler.minRegisteredResourcesRatio}} is set to a large
> number (e.g., > 0.8 in this case), the app will hang and never finish.
> Case 2: if a small app's coresPerExecutor is larger than its requested cores
> (e.g., {{spark.cores.max = 10}}, {{spark.executor.cores = 16}}), {{val
> keepScheduling = coresToAssign >= minCoresPerExecutor}} is always FALSE. As a
> result, this app will never get an executor to run.
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