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From Ankur Gupta <ankur.gu...@cloudera.com.INVALID>
Subject Re: [DISCUSS] Enable blacklisting feature by default in 3.0
Date Fri, 29 Mar 2019 20:48:08 GMT
Thanks Reynold! That is certainly useful to know.

@Chris Will it be possible for you to send out those details if you still
have them or better create a JIRA, so someone can work on those
improvements. If there is already a JIRA, can you please provide a link to
the same.

Additionally, if the concern is with the aggressiveness of the
blacklisting, then we can enable blacklisting feature by default with
higher thresholds for failures. Below is an alternate set of defaults that
were also proposed in the design document for max cluster utilization:

   1. spark.blacklist.task.maxTaskAttemptsPerExecutor = 2
   2. spark.blacklist.task.maxTaskAttemptsPerNode = 2
   3. spark.blacklist.stage.maxFailedTasksPerExecutor = 5
   4. spark.blacklist.stage.maxFailedExecutorsPerNode = 4
   5. spark.blacklist.application.maxFailedTasksPerExecutor = 5
   6. spark.blacklist.application.maxFailedExecutorsPerNode = 4
   7. spark.blacklist.timeout = 5 mins



On Fri, Mar 29, 2019 at 11:18 AM Reynold Xin <rxin@databricks.com> wrote:

> We tried enabling blacklisting for some customers and in the cloud, very
> quickly they end up having 0 executors due to various transient errors. So
> unfortunately I think the current implementation is terrible for cloud
> deployments, and shouldn't be on by default. The heart of the issue is that
> the current implementation is not great at dealing with transient errors vs
> catastrophic errors.
>
> +Chris who was involved with those tests.
>
>
>
> On Thu, Mar 28, 2019 at 3:32 PM, Ankur Gupta <
> ankur.gupta@cloudera.com.invalid> wrote:
>
>> Hi all,
>>
>> This is a follow-on to my PR: https://github.com/apache/spark/pull/24208,
>> where I aimed to enable blacklisting for fetch failure by default. From the
>> comments, there is interest in the community to enable overall blacklisting
>> feature by default. I have listed down 3 different things that we can do
>> and would like to gather feedback and see if anyone has objections with
>> regards to this. Otherwise, I will just create a PR for the same.
>>
>> 1. *Enable blacklisting feature by default*. The blacklisting feature
>> was added as part of SPARK-8425 and is available since 2.2.0. This feature
>> was deemed experimental and was disabled by default. The feature blacklists
>> an executor/node from running a particular task, any task in a particular
>> stage or all tasks in application based on number of failures. There are
>> various configurations available which control those thresholds.
>> Additionally, the executor/node is only blacklisted for a configurable time
>> period. The idea is to enable blacklisting feature with existing defaults,
>> which are following:
>>
>>    1. spark.blacklist.task.maxTaskAttemptsPerExecutor = 1
>>    2. spark.blacklist.task.maxTaskAttemptsPerNode = 2
>>    3. spark.blacklist.stage.maxFailedTasksPerExecutor = 2
>>    4. spark.blacklist.stage.maxFailedExecutorsPerNode = 2
>>    5. spark.blacklist.application.maxFailedTasksPerExecutor = 2
>>    6. spark.blacklist.application.maxFailedExecutorsPerNode = 2
>>    7. spark.blacklist.timeout = 1 hour
>>
>> 2. *Kill blacklisted executors/nodes by default*. This feature was added
>> as part of SPARK-16554 and is available since 2.2.0. This is a follow-on
>> feature to blacklisting, such that if an executor/node is blacklisted for
>> the application, then it also terminates all running tasks on that executor
>> for faster failure recovery.
>>
>> 3. *Remove legacy blacklisting timeout config*
>> : spark.scheduler.executorTaskBlacklistTime
>>
>> Thanks,
>> Ankur
>>
>
>

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