Thank you very much Tom!
regards, Arinto Arinto Murdopo European Master in Distributed Computing (EMDC) Universitat Politècnica de Catalunya · BarcelonaTech, Barcelona, Spain KTH Royal Institute of Technology, Stockholm, Sweden Phone: +46 725 548 759 On Fri, Nov 9, 2012 at 1:25 AM, Thomas Graves <tgra...@yahoo-inc.com> wrote: > With YARN you now have applications. This is how the RM (resource manager) > views things. MapReduce is one type of application. An RMAppAttempt is > an attempt to run one particular application. During the execution of that > application something might go wrong which causes it to die before the > application finishes. For instance the node the application master is on > dies. The RM will then try to run that application again - a second > attempt. There is a configuration that controls how many attempts to run > that application you make before giving up. You application can chose to > handle re-attempts. For instance the MapReduce application knows its a > second (or third or etc..) attempt, reads the job history file and only > re-runs the tasks that haven't finished. > > A task-attempt is at the MapReduce application level. A Task in this case > is either a map or a reduce task. An attempt again is just one attempt at > running a single map or reduce. That single attempt can fail for lots of > reasons - host goes down, etc. The mapreduce application master will > rerun that task (thus a second attempt) up to whatever is configured. > > Tom > > On 11/8/12 4:22 PM, "Arinto Murdopo" <ari...@gmail.com> wrote: > > >Hi guys, > > > >I have several questions related to YARN source code: > >1. what is "task-attempt" in the this document ( > >https://issues.apache.org/jira/secure/attachment/12486023/MapR) ? > >2. what is RMAppAttempt ? the documentation in the code mentions that > >RMApp > >may have multiple RMAppAttempt but I still could not reason what is > >RMAppAttempt and why do we need this. > > > >regards, > > > >Arinto Murdopo > >European Master in Distributed Computing (EMDC) > >Universitat Politècnica de Catalunya · BarcelonaTech, Barcelona, Spain > >KTH Royal Institute of Technology, Stockholm, Sweden > >Phone: +46 725 548 759 > >
