The memory size allocated by YARN to Container in the Hadoop system can be set by the parameter yarn.app.mapreduce am.resource.mb

Question

Options

• ATrue
• BFalse

• A
  24% (8)
• B
  76% (26)

Explanation

Option B is correct because yarn.app.mapreduce.am.resource.mb controls memory only for the Application Master (AM) container - the coordinator process that manages the MapReduce job lifecycle - not for general task containers. The "am" in the parameter name is the giveaway that this is AM-specific.

To set memory for actual map and reduce task containers, the correct parameters are mapreduce.map.memory.mb and mapreduce.reduce.memory.mb respectively. For node-level container memory limits, yarn.nodemanager.resource.memory-mb is the relevant setting.

Option A (True) is wrong because it incorrectly generalizes this parameter's scope - conflating the Application Master container with all YARN containers is a common misconception the exam is testing.

Memory tip: Decode the parameter name literally - yarn.app.mapreduce.**am**.resource.mb - the am stands for Application Master. If the parameter is about the AM, it only controls the AM's memory, not the workers'. Whenever you see am sandwiched in a YARN parameter, think "coordinator, not workers."

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