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From sandeep das <yarnhad...@gmail.com>
Subject Re: Max Parallel task executors
Date Mon, 09 Nov 2015 04:13:27 GMT
Thanks Brahma and Laxman for your valuable input.

Following are the statistics available on YARN RM GUI.

Memory Used : 0 GB
Memory Total : 64 GB (16*4 = 64 GB)
VCores Used: 0
VCores Total: 320 (Earlier I had mentioned that I've configured 40 Vcores
but recently I increased to 80 that's why its appearing 80*4 = 321)

Note: These statistics were captured when there was no job running in
background.

Let me know whether it was sufficient to nail the issue. If more
information is required please let me know.

Regards,
Sandeep


On Fri, Nov 6, 2015 at 7:04 PM, Brahma Reddy Battula <
brahmareddy.battula@huawei.com> wrote:

>
> The formula for determining the number of concurrently running tasks per
> node is:
>
> *min *(*yarn.nodemanager.resource.memory-mb /
> mapreduce.[map|reduce].memory.mb*,
>      *yarn.nodemanager.resource.cpu-vcores /
> mapreduce.[map|reduce].cpu.vcores*) .
>
>
> *For you scenario :*
>
> As you told yarn.nodemanager.resource.memory-mb is configured to *16 GB*
> and yarn.nodemanager.resource.cpu-vcores configured to *40*. and I am
> thinking
> mapreduce.map/reduce.memory.mb, mapreduce.map/reduce.cpu.vcores default
> values.
>
> min (16GB/1GB,40Core/1Core )=*16* tasks for Node*. *Then total should be
> 16*4=64  (63+1AM)..
>
> I am thinking, Two Nodemanger's are unhealthy *(OR)* you might have
> configured mapreduce.map/reduce.memory.mb=2GB(or 5 core).
>
> As laxman pointed you can post RMUI or you can cross check like above.
>
> Hope this helps.
>
>
>
> Thanks & Regards
>
>  Brahma Reddy Battula
>
>
>
>
> ------------------------------
> *From:* Laxman Ch [laxman.lux@gmail.com]
> *Sent:* Friday, November 06, 2015 6:31 PM
> *To:* user@hadoop.apache.org
> *Subject:* Re: Max Parallel task executors
>
> Can you please copy paste the cluster metrics from RM dashboard.
> Its under http://rmhost:port/cluster/cluster
>
> In this page, check under Memory Total vs Memory Used and VCores Total vs
> VCores Used
>
> On 6 November 2015 at 18:21, sandeep das <yarnhadoop@gmail.com> wrote:
>
>> HI Laxman,
>>
>> Thanks for your response. I had already configured a very high value for yarn.nodemanager.resource.cpu-vcores
>> e.g. 40 but still its not increasing more number of parallel tasks to
>> execute but if this value is reduced then it runs less number of parallel
>> tasks.
>>
>> As of now yarn.nodemanager.resource.memory-mb is configured to 16 GB and yarn.nodemanager.resource.cpu-vcores
>> configured to 40.
>>
>> Still its not spawning more tasks than 31.
>>
>> Let me know if more information is required to debug it. I believe there
>> is upper limit after which yarn stops spawning tasks. I may be wrong here.
>>
>>
>> Regards,
>> Sandeep
>>
>> On Fri, Nov 6, 2015 at 6:15 PM, Laxman Ch <laxman.lux@gmail.com> wrote:
>>
>>> Hi Sandeep,
>>>
>>> Please configure the following items to the cores and memory per node
>>> you wanted to allocate for Yarn containers.
>>> Their defaults are 8 cores and 8GB. So that's the reason you were stuck
>>> at 31 (4nodes * 8cores - 1 AppMaster)
>>>
>>>
>>> http://hadoop.apache.org/docs/r2.6.0/hadoop-yarn/hadoop-yarn-common/yarn-default.xml
>>> yarn.nodemanager.resource.cpu-vcores
>>> yarn.nodemanager.resource.memory-mb
>>>
>>>
>>> On 6 November 2015 at 17:59, sandeep das <yarnhadoop@gmail.com> wrote:
>>>
>>>> May be to naive to ask but How do I check that?
>>>> Sometimes there are almost 200 map tasks pending to run but at a time
>>>> only 31 runs.
>>>>
>>>> On Fri, Nov 6, 2015 at 5:57 PM, Chris Mawata <chris.mawata@gmail.com>
>>>> wrote:
>>>>
>>>>> Also check that you have more than 31 blocks to process.
>>>>> On Nov 6, 2015 6:54 AM, "sandeep das" <yarnhadoop@gmail.com> wrote:
>>>>>
>>>>>> Hi Varun,
>>>>>>
>>>>>> I tried to increase this parameter but it did not increase number
of
>>>>>> parallel tasks but if It is decreased then YARN reduces number of
parallel
>>>>>> tasks. I'm bit puzzled why its not increasing more than 31 tasks
even after
>>>>>> its value is increased.
>>>>>>
>>>>>> Is there any other configuration as well which controls on how many
>>>>>> maximum tasks can execute in parallel?
>>>>>>
>>>>>> Regards,
>>>>>> Sandeep
>>>>>>
>>>>>> On Tue, Nov 3, 2015 at 7:29 PM, Varun Vasudev <vvasudev@apache.org>
>>>>>> wrote:
>>>>>>
>>>>>>> The number of parallel tasks that are run depends on the amount
of
>>>>>>> memory and vcores on your machines and the amount of memory and
vcores
>>>>>>> required by your mappers and reducers. The amount of memory can
be set
>>>>>>> via yarn.nodemanager.resource.memory-mb(the default is 8G). The
amount of
>>>>>>> vcores can be set via yarn.nodemanager.resource.cpu-vcores(the
>>>>>>> default is 8 vcores).
>>>>>>>
>>>>>>> -Varun
>>>>>>>
>>>>>>> From: sandeep das <yarnhadoop@gmail.com>
>>>>>>> Reply-To: <user@hadoop.apache.org>
>>>>>>> Date: Monday, November 2, 2015 at 3:56 PM
>>>>>>> To: <user@hadoop.apache.org>
>>>>>>> Subject: Max Parallel task executors
>>>>>>>
>>>>>>> Hi Team,
>>>>>>>
>>>>>>> I've a cloudera cluster of 4 nodes. Whenever i submit a job my
only
>>>>>>> 31 parallel tasks are executed whereas my machines have more
CPU available
>>>>>>> but still YARN/AM does not create more task.
>>>>>>>
>>>>>>> Is there any configuration which I can change to start more
>>>>>>> MAP/REDUCER task in parallel?
>>>>>>>
>>>>>>> Each machine in my cluster has 24 CPUs.
>>>>>>>
>>>>>>> Regards,
>>>>>>> Sandeep
>>>>>>>
>>>>>>
>>>>>>
>>>>
>>>
>>>
>>> --
>>> Thanks,
>>> Laxman
>>>
>>
>>
>
>
> --
> Thanks,
> Laxman
>

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