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https://issues.apache.org/jira/browse/SPARK-23423?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16370074#comment-16370074
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Stavros Kontopoulos edited comment on SPARK-23423 at 2/20/18 2:04 PM:
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[~igor.berman] Thnx for supplying the info. We are aware of SPARK-19755
actually we wanted to fix this for quite some time. The hardcoded value is not
the way to go for sure. One note here though.. try to avoid also the failure of
the executors in the first place, even if you tolerate more failures they
shouldnt fail. You can allocate different port ranges AFIK for your tasks or by
default ports are random from what I recall, and the next port is tried if
there is a collision. I am still curious how they fail... maybe there is an
issue there as well... [~susanxhuynh]
was (Author: skonto):
[~igor.berman] Thnx for supplying the info. We are aware of SPARK-19755
actually we want to fix this for quite some time. The hardcoded value is not
the way to go for sure. One note here though.. try to avoid also the failure of
the executors in the first place, even if you tolerate more failures they
shouldnt fail. You can allocate different port ranges AFIK for your tasks or by
default ports are random from what I recall, and the next port is tried if
there is a collision. I am still curious how they fail... maybe there is an
issue there as well...
> Application declines any offers when killed+active executors rich
> spark.dynamicAllocation.maxExecutors
> ------------------------------------------------------------------------------------------------------
>
> Key: SPARK-23423
> URL: https://issues.apache.org/jira/browse/SPARK-23423
> Project: Spark
> Issue Type: Bug
> Components: Mesos, Spark Core
> Affects Versions: 2.2.1
> Reporter: Igor Berman
> Priority: Major
> Labels: Mesos, dynamic_allocation
>
> Hi
> Mesos Version:1.1.0
> I've noticed rather strange behavior of MesosCoarseGrainedSchedulerBackend
> when running on Mesos with dynamic allocation on and limiting number of max
> executors by spark.dynamicAllocation.maxExecutors.
> Suppose we have long running driver that has cyclic pattern of resource
> consumption(with some idle times in between), due to dyn.allocation it
> receives offers and then releases them after current chunk of work processed.
> Since at
> [https://github.com/apache/spark/blob/master/resource-managers/mesos/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosCoarseGrainedSchedulerBackend.scala#L573]
> the backend compares numExecutors < executorLimit and
> numExecutors is defined as slaves.values.map(_.taskIDs.size).sum and slaves
> holds all slaves ever "met", i.e. both active and killed (see comment
> [https://github.com/apache/spark/blob/master/resource-managers/mesos/src/main/scala/org/apache/spark/scheduler/cluster/mesos/MesosCoarseGrainedSchedulerBackend.scala#L122)]
>
> On the other hand, number of taskIds should be updated due to statusUpdate,
> but suppose this update is lost(actually I don't see logs of 'is now
> TASK_KILLED') so this number of executors might be wrong
>
> I've created test that "reproduces" this behavior, not sure how good it is:
> {code:java}
> //MesosCoarseGrainedSchedulerBackendSuite
> test("max executors registered stops to accept offers when dynamic allocation
> enabled") {
> setBackend(Map(
> "spark.dynamicAllocation.maxExecutors" -> "1",
> "spark.dynamicAllocation.enabled" -> "true",
> "spark.dynamicAllocation.testing" -> "true"))
> backend.doRequestTotalExecutors(1)
> val (mem, cpu) = (backend.executorMemory(sc), 4)
> val offer1 = createOffer("o1", "s1", mem, cpu)
> backend.resourceOffers(driver, List(offer1).asJava)
> verifyTaskLaunched(driver, "o1")
> backend.doKillExecutors(List("0"))
> verify(driver, times(1)).killTask(createTaskId("0"))
> val offer2 = createOffer("o2", "s2", mem, cpu)
> backend.resourceOffers(driver, List(offer2).asJava)
> verify(driver, times(1)).declineOffer(offer2.getId)
> }{code}
>
>
> Workaround: Don't set maxExecutors with dynamicAllocation on
>
> Please advice
> Igor
> marking you friends since you were last to touch this piece of code and
> probably can advice something([~vanzin], [~skonto], [~susanxhuynh])
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