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Bo Wang commented on MAPREDUCE-4495: ------------------------------------ [~mayank_bansal] I will post a design document soon. For the place to store WF state, initially it will be kept in memory. Later it could be persisted to a file in HDFS. DAG AM will run a single WF, so no DB is required here. > Workflow Application Master in YARN > ----------------------------------- > > Key: MAPREDUCE-4495 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-4495 > Project: Hadoop Map/Reduce > Issue Type: New Feature > Affects Versions: 2.0.0-alpha > Reporter: Bo Wang > Assignee: Bo Wang > > It is useful to have a workflow application master, which will be capable of > running a DAG of jobs. The workflow client submits a DAG request to the AM > and then the AM will manage the life cycle of this application in terms of > requesting the needed resources from the RM, and starting, monitoring and > retrying the application's individual tasks. > Compared to running Oozie with the current MapReduce Application Master, > these are some of the advantages: > - Less number of consumed resources, since only one application master will > be spawned for the whole workflow. > - Reuse of resources, since the same resources can be used by multiple > consecutive jobs in the workflow (no need to request/wait for resources for > every individual job from the central RM). > - More optimization opportunities in terms of collective resource requests. > - Optimization opportunities in terms of rewriting and composing jobs in the > workflow (e.g. pushing down Mappers). > - This Application Master can be reused/extended by higher systems like Pig > and hive to provide an optimized way of running their workflows. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira