Hi Michele,

configuring a YARN cluster to allocate all available resources as good as
possible is sometimes tricky, that is true.
We are aware of these problems and there are actually the following two
JIRAs for this:
https://issues.apache.org/jira/browse/FLINK-937 (Change the YARN Client to
allocate all cluster resources, if no argument given) --> I think the
consensus on the issue was give users an option to allocate everything (so
don't do it by default)
https://issues.apache.org/jira/browse/FLINK-1288 (YARN ApplicationMaster
sometimes fails to allocate the specified number of workers)

How many NodeManager's is YARN reporting in the ResourceManager UI? (in
"Active Nodes" column) (I suspect 6?)
How much memory per NodeManager is YARN reporting? (You can see this in the
"Nodes" page of the RM)

> I would like to run 5 nodes with 8 slots each, is it correct?

Yes.


> Then i reduced memories, everything started but i get a runtime error of
missing buffer

What exactly is the exception?
I guess you have to give the system a few more network buffers using the
taskmanager.network.numberOfBuffers config parameter.

> Can someone help me syep-by-step in a good configuration for such
cluster? I think the documentation is really missing details

When starting Flink on YARN, there are usually some WARN log messages in
the beginning when the system detects that specified containers will not
fit in the cluster.
Also, in the ResourceManager UI, you can see the status of the scheduler.
This often helps to understand what's going on, resource-wise.



On Fri, Jul 24, 2015 at 3:58 PM, Michele Bertoni <
michele1.bert...@mail.polimi.it> wrote:

>  Hi everybody, i need a help on how to configure a yarn cluster
> I tried a lot of conf but none of them was correct
>
> We have a cluster on amazon emr let's say 1manager+5worker all of them are
> m3.2xlarge then 8 core each and 30 GB of RAM each
>
> What is a good configuration for such cluster?
>
> I would like to run 5 nodes with 8 slots each, is it correct?
>
> Now the problems: by now i run all tests mistakenly using 40 task managers
> each with 2048MB and 1 slot (at least it was working)
>
> Today i found the error and i tried run 5 task manager and setting a
> default slot in conf-yaml of 8, giving a task manager memory of 23040 (-tm
> 23040) that is the limit allowed by yarn but i am getting errors: one TM is
> not running because there is no available memory. it seems like the jm is
> not using memory from the master but from the nodes (in fact yarn says TM
> number 5 is missing 2048 that is the memory for the jm)
>
> Then i reduced memories, everything started but i get a runtime error of
> missing buffer
>
> Can someone help me syep-by-step in a good configuration for such cluster?
> I think the documentation is really missing details
>
> Thanks a lot
> Best
> Michele
>

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