Thank You very much if it is the case then ApplicationMaster alone takes alomst 
everything that my datanode can offer - that would explain why task itself 
can't start. Thank You very much again.
Dnia 17 listopada 2015 20:40 Bikas Saha <bi...@apache.org> napisał(a):
You can check for “yarn.app.mapreduce.am.resource.mb” in your configs. Its 
default is 1.5GB and other MR task defaults are 1GB. From: darekg11 
[mailto:darek...@tlen.pl]
Sent: Tuesday, November 17, 2015 11:34 AM
To: user@hadoop.apache.org
Subject: RE: Does MapReduceApplicationMaster prevents data node from spawning 
YarnChild? Thank You very much, will check but the problem is that machines 
aren't really powerful - only 2GB of RAM and 2xCore each at 3.3GHz.
Do You maybe know approx value of required resources for AppMaster? And can we 
check current resource consumption of AppMaster?
Dnia 17 listopada 2015 18:40 Bikas Saha <bi...@apache.org> napisał(a):No. 
In general App Masters and their containers can be launched on any machine and 
both can be launched on the same machine. If your case happens repeatedly then 
you could check the RM UI, while the job is running, to see the maximum 
resource on a node manager and the resource currently assigned. Perhaps your 
node managers don’t have enough resources to run multiple containers? From: 
darekg11 [mailto:darek...@tlen.pl]
Sent: Tuesday, November 17, 2015 7:55 AM
To: user@hadoop.apache.org
Subject: Does MapReduceApplicationMaster prevents data node from spawning 
YarnChild? Hello again dear users.
Today I ran into following problem:
My mini cluster consist of:
1 NameNode and 2 SlaveNodes.
When I ran my MapReduce program written in java with number of reducers equals 
to two.
As the result on first SlaveNode I got MRAppMaster task and only the second 
slave launched Yarn Child which actually was producing output results.
I understand that MRAppMaster is essential process repsonsible for managing 
life of given task.
And because of that single slave node can't launch MrAppMaster and Yarn Child 
at the same time or am I misunderstanding something? 

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