Amazon Elastic MapReduce
Developer Guide

Hadoop Configuration Reference

This documentation is for AMI versions 2.x and 3.x of Amazon EMR. See the Amazon EMR Release Guide for information about Amazon EMR releases 4.0.0 and above. For information about managing the Amazon EMR service in 4.x releases, see the Amazon EMR Management Guide.

Apache Hadoop runs on the EC2 instances launched in a cluster. Amazon Elastic MapReduce (Amazon EMR) defines a default configuration for Hadoop, depending on the Amazon Machine Image (AMI) that you specify when you launch the cluster. For more information about the supported AMI versions, see Choose an Amazon Machine Image (AMI).


Although Amazon EMR makes an effort to provide optimal configuration settings for each instance type for the broadest range of use cases, it is possible that you may need to manually adjust these settings for the needs of your application.

The following sections describe the various configuration settings and mechanisms available in Amazon EMR.