Which process instantiates user code, and executes map and reduce tasks on a cluster running
MapReduce v2 (MRv2) on YARN?
A.
NodeManager
B.
ApplicationMaster
C.
TaskTracker
D.
JobTracker
E.
NameNode
F.
DataNode
G.
ResourceManager
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in RMv2 job traker doesn’t exist any more the answer is A
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Why not B please ? ApplicationMasters launch tasks in containers within NodeManagers ?
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Answer: B
http://hadoop.apache.org/docs/current/hadoop-yarn/hadoop-yarn-site/YARN.html
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A
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B seems to be the correct answer as YarnChild is executed on request from ApplicationMaster. where as runJar is Application master.
[hduser@cdh-master ~]$ jps
15338 NameNode
19939 YarnChild
15808 ResourceManager
20209 Jps
15651 SecondaryNameNode
19039 RunJar
19365 MRAppMaster
19918 YarnChild
5634 JobHistoryServer
19892 YarnChild
19893 YarnChild
20015 YarnChild
19959 YarnChild
15466 DataNode
15908 NodeManager
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I don’t think Application Master (AM) is correct answer, because, AM coordinates Tasks running the MR Job. AM and MR Tasks run in Containers what scheduled by Resource Manager and managed by NMs.
from the book “The Definitive Guide 4th Edition”
Figure 7-1: How Hadoop runs a MapReduce job
Task Execution:
Once a task has been assigned resources for a container on a particular node by the
resource manager’s scheduler, the application master starts the container by contacting
the node manager.
The task is executed by a Java application whose main class is YarnChild.
Before it can run the task, it localizes the resources that the task needs, including the job configuration and JAR file, and any files.
Finally, it runs the map or reduce task.
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Answer : A .
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A
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From cloudera training doc
NodeManager
– Manages life/cycle of containers
– Launches Map and Reduce tasks in containers
– Monitors resource consumption
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A
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Correct answer is G – Resource Manager
http://www.aiotestking.com/cloudera/which-process-instantiates-user-code-and-executes-map-and-reduce-tasks-on-a-cluster-running-mapreduce-v2-mrv2-on-yarn/
The MapReduce Job Lifecycle in YARN
User submits an app request by passing config for Application Manager to Resource Manager.
1. Resource Manager allocates a container for Application Manager on a node. Tells Node Manager in charge of that node to launch the Application Manager container.
2. Application Manager registers back with Resource Manager. Asks for more containers to run tasks.
3. Resource Manager allocates the containers on different nodes in the cluster.
4.. Application Manager talks directly to the Node Managers on those nodes to launch the containers for tasks.
5.Application Manager monitors the progress of the tasks.
6. When all the application’s tasks are done, Application Manager unregisters itself from Resource Manager.
7. Resource Manager reclaims the previously allocated containers for the application
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Job tracker
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PLEASE BROTHER DON”T COMMENT I THINK YOU ARE THE DUMB PERSON WHO IS COMMENTING AND CONFUSING ALL.
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its E , job tracker
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I agree with the answer. D
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