hadoop-mapreduce-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Sunil Govind <sunil.gov...@gmail.com>
Subject Re: YARN cluster underutilization
Date Wed, 25 May 2016 18:07:16 GMT
Hi Jeff,

 I do see the yarn.resourcemanager.nodemanagers.heartbeat-interval-ms
property set to 1000 in the job configuration
>> Ok, This make sense.. node heartbeat seems default.

If there are no locality specified in resource requests (using
ResourceRequest.ANY) , then YARN will allocate only one container per node
heartbeat. So your container allocation rate is slower considering 600k
requests and only 20 nodes. And if more number of containers are also
getting released fast (I could see that some containers lifetime is 80 to
90 secs), then this will become more complex and container allocation rate
will be slower.

YARN-4963 <https://issues.apache.org/jira/browse/YARN-4963> is trying to
make more allocation per heartbeat for NODE_OFFSWITCH (ANY) requests. But
its not yet available in any release.

I guess you can investigate more in this line to confirm this points.

Thanks
Sunil


On Wed, May 25, 2016 at 11:00 PM Guttadauro, Jeff <jeff.guttadauro@here.com>
wrote:

> Thanks for digging into the log, Sunil, and making some interesting
> observations!
>
>
>
> The heartbeat interval hasn’t been changed from its default, and I do see
> the yarn.resourcemanager.nodemanagers.heartbeat-interval-ms property set to
> 1000 in the job configuration.  I was searching in the log for heartbeat
> interval information, but I didn’t find anything.  Where do you look in the
> log for the heartbeats?
>
>
>
> Also, you are correct about there being no data locality, as all the input
> data is in S3.  The utilization has been fluctuating, but I can’t really
> see a pattern or tell why.  It actually started out pretty low in the
> 20-30% range and then managed to get up into the 50-70% range after a
> while, but that was short-lived, as it went back down into the 20-30% range
> for quite a while.  While writing this, I saw it surprisingly hit 80%!!
> First time I’ve seen it that high in the 20 hours it’s been running…
>  Although looks like it may be headed back down.  I’m perplexed.  Wouldn’t
> you generally expect fairly stable utilization over the course of the job?
> (This is the only job running.)
>
>
>
> Thanks,
>
> -Jeff
>
>
>
> *From:* Sunil Govind [mailto:sunil.govind@gmail.com]
> *Sent:* Wednesday, May 25, 2016 11:55 AM
>
>
> *To:* Guttadauro, Jeff <jeff.guttadauro@here.com>; user@hadoop.apache.org
> *Subject:* Re: YARN cluster underutilization
>
>
>
> Hi Jeff.
>
>
>
> Thanks for sharing this information. I have some observations from this
> logs.
>
>
>
> - I think the node heartbeat is around 2/3 seconds here. Is it changed due
> to some other reasons?
>
> - And all mappers Resource Request seems to be asking for type ANY (there
> is no data locality). pls correct me if I am wrong.
>
>
>
> If the resource request type is ANY, only one container will be allocated
> per heartbeat for a node. Here node heartbeat delay is also more. And I can
> see that containers are released very fast too. So when u started you
> application, are you seeing more better resource utilization? And once
> containers started to get released/completed, you are seeing under
> utilization.
>
>
>
> Pls look into this line. It may be a reason.
>
>
>
> Thanks
>
> Sunil
>
>
>
> On Wed, May 25, 2016 at 9:59 PM Guttadauro, Jeff <jeff.guttadauro@here.com>
> wrote:
>
> Thanks for your thoughts thus far, Sunil.  Most grateful for any
> additional help you or others can offer.  To answer your questions,
>
>
>
> 1.       This is a custom M/R job, which uses mappers only (no reduce
> phase) to process GPS probe data and filter based on inclusion within a
> provided polygon.  There is actually a lot of upfront work done in the
> driver to make that task as simple as can be (identifies a list of tiles
> that are completely inside the polygon and those that fall across an edge,
> for which more processing would be needed), but the job would still be more
> compute-intensive than wordcount, for example.
>
>
>
> 2.       I’m running almost 84k mappers for this job.  This is actually
> down from ~600k mappers, since one other thing I’ve done is increased the
> mapreduce.input.fileinputformat.split.minsize to 536870912 (512M) for the
> job.  Data is in S3, so loss of locality isn’t really a concern.
>
>
>
> 3.       For NodeManager configuration, I’m using EMR’s default
> configuration for the m3.xlarge instance type, which is
> yarn.scheduler.minimum-allocation-mb=32,
> yarn.scheduler.maximum-allocation-mb=11520, and
> yarn.nodemanager.resource.memory-mb=11520.  YARN dashboard shows min/max
> allocations of <memory:32, vCores:1>/<memory:11520, vCores:8>.
>
>
>
> 4.       Capacity Scheduler [MEMORY]
>
>
>
> 5.       I’ve attached 2500 lines from the RM log.  Happy to grab more,
> but they are pretty big, and I thought that might be sufficient.
>
>
>
> Any guidance is much appreciated!
>
> -Jeff
>
>
>
> *From:* Sunil Govind [mailto:sunil.govind@gmail.com]
> *Sent:* Wednesday, May 25, 2016 10:55 AM
> *To:* Guttadauro, Jeff <jeff.guttadauro@here.com>; user@hadoop.apache.org
> *Subject:* Re: YARN cluster underutilization
>
>
>
> Hi Jeff,
>
>
>
> It looks like to you are allocating more memory for AM container. Mostly
> you might not need 6Gb (as per the log). Could you please help  to provide
> some more information.
>
>
>
> 1. What type of mapreduce application (wordcount etc) are you running?
> Some AMs may be CPU intensive and some may not be. So based on the type
> application, memory/cpu can be tuned for better utilization.
>
> 2. How many mappers (reducers) are you trying to run here?
>
> 3. You have mentioned that each node has 8 cores and 15GB, but how much is
> actually configured for NM?
>
> 4. Which scheduler are you using?
>
> 5. Its better to attach RM log if possible.
>
>
>
> Thanks
>
> Sunil
>
>
>
> On Wed, May 25, 2016 at 8:58 PM Guttadauro, Jeff <jeff.guttadauro@here.com>
> wrote:
>
> Hi, all.
>
>
>
> I have an M/R (map-only) job that I’m running on a Hadoop 2.7.1 YARN
> cluster that is being quite underutilized (utilization of around 25-30%).
> The EMR cluster is 1 master + 20 core m3.xlarge nodes, which have 8 cores
> each and 15G total memory (with 11.25G of that available to YARN).  I’ve
> configured mapper memory with the following properties, which should allow
> for 8 containers running map tasks per node:
>
>
>
> <property><name>mapreduce.map.memory.mb</name><value>1440</value></property>
> <!-- Container size -->
>
> <property><name>mapreduce.map.java.opts</name><value>-Xmx1024m</value></property>
> <!-- JVM arguments for a Map task -->
>
>
>
> It was suggested that perhaps my AppMaster was having trouble keeping up
> with creating all the mapper containers and that I bulk up its resource
> allocation.  So I did, as shown below, providing it 6G container memory (5G
> task memory), 3 cores, and 60 task listener threads.
>
>
>
> <property><name>yarn.app.mapreduce.am.job.task.listener.thread-count</name><value>60</value></property>
> <!-- App Master task listener threads -->
>
> <property><name>yarn.app.mapreduce.am.resource.cpu-vcores</name><value>3</value></property>
> <!-- App Master container vcores -->
>
> <property><name>yarn.app.mapreduce.am.resource.mb</name><value>6400</value></property>
> <!-- App Master container size -->
>
> <property><name>yarn.app.mapreduce.am.command-opts</name><value>-Xmx5120m</value></property>
> <!-- JVM arguments for each Application Master -->
>
>
>
> Taking a look at the node on which the AppMaster is running, I'm seeing
> plenty of CPU idle time and free memory, yet there are still nodes with no
> utilization (0 running containers).  The log indicates that the AppMaster
> has way more memory (physical/virtual) than it appears to need with
> repeated log messages like this:
>
>
>
> 2016-05-25 13:59:04,615 INFO
> org.apache.hadoop.yarn.server.nodemanager.containermanager.monitor.ContainersMonitorImpl
> (Container Monitor): Memory usage of ProcessTree 11265 for container-id
> container_1464122327865_0002_01_000001: 1.6 GB of 6.3 GB physical memory
> used; 6.1 GB of 31.3 GB virtual memory used
>
>
>
> Can you please help me figure out where to go from here to troubleshoot,
> or any other things to try?
>
>
>
> Thanks!
>
> -Jeff
>
>
>
>

Mime
View raw message