Try looking at how the mapreduce code does it. I think you have to put in a
fully qualified host name, but I don't remember for sure.
--Bobby Evans
On 1/4/12 10:04 PM, "raghavendhra rahul" <raghavendhrara...@gmail.com> wrote:
Hi,
I tried to set the client node for launching the container within the
application master.
I have set the parameter as
request.setHostName("client");
but the containers are not launched in the destined host.Instead the loop goes
on continuously.
2012-01-04 15 <tel:2012-01-04%2015> :11:48,535 INFO
appmaster.ApplicationMaster (ApplicationMaster.java:run(204)) - Current
application state: loop=95, appDone=false, total=2, requested=2, completed=0,
failed=0, currentAllocated=0
On Wed, Jan 4, 2012 at 11:24 PM, Robert Evans <ev...@yahoo-inc.com> wrote:
Ann,
A container more or less corresponds to a task in MRV1. There is one exception
to this, as the ApplicationMaster also runs in a container. The
ApplicationMaster will request new containers for each mapper or reducer task
that it wants to launch. There is separate code from the container that will
serve up the intermediate mapper output and is run as part of the NodeManager
(Similar to the TaskTracker from before). When the ApplicationMaster requests
a container it also includes with it a hint as to where it would like the
container placed. In fact it actually makes three request one for the exact
node, one for the rack the node is on, and one that is generic and could be
anywhere. The scheduler will try to honor those requests in the same order so
data locality is still considered and generally honored. Yes there is the
possibility of back and forth to get a container, but the ApplicationMaster
generally will try to use all of the containers that it is given, even if they
are not optimal.
--Bobby Evans
On 1/4/12 10:23 AM, "Ann Pal" <ann_r_...@yahoo.com <http://ann_r_...@yahoo.com>
> wrote:
Hi,
I am trying to understand more about Hadoop Next Gen Map Reduce and had the
following questions based on the following post:
http://developer.yahoo.com/blogs/hadoop/posts/2011/03/mapreduce-nextgen-scheduler/
[1] How does application decide how many containers it needs? The containers
are used to store the intermediate result at the map nodes?
[2] During resource allocation, if the resource manager has no mapping between
map tasks to resources allocated, how can it properly allocate the right
resources. It might end up allocating resources on a node, which does not have
data for the map task, and hence is not optimal. In this case the Application
Master will have to reject it and request again . There could be considerable
back- and- forth between application master and resource manager before it
could converge. Is this right?
Thanks!
