MapR 5.1 is at End of Life (EOL) and no longer supported. Please see the latest documentation. This documentation is not being updated.

5.1 Reference
This section provides information about development content including MapR-FS and MapReduce development topics and reference content.
- Development Guide
- Reference Guide
  - MapR Control System
  - Hadoop Commands
    - Overview
    - hadoop archive
      The hadoop archive command creates a Hadoop archive, a file that contains other files. A Hadoop archive always has a *.har extension.
    - hadoop classpath
      The hadoop classpath command prints the class path needed to access the Hadoop jar and the required libraries.
    - hadoop daemonlog
      The hadoop daemonlog command gets and sets the log level for each daemon.
    - hadoop distcp
    - hadoop fs
    - hadoop jar
      The hadoop jar command runs a program contained in a JAR file. Users can bundle their MapReduce code in a JAR file and execute it using this command.
    - hadoop job
      The hadoop job command enables you to manage MapReduce jobs.
    - hadoop mfs
      The hadoop mfs command performs operations on directories in the cluster.
    - hadoop mradmin
      The hadoop mradmin command runs Map-Reduce administrative commands.
    - hadoop pipes
    - hadoop queue
      The hadoop queue command displays job queue information.
    - hadoop version
      The hadoop version command prints the hadoop software version.
    - hadoop conf
      The hadoop conf command outputs the configuration information for this node to standard output.
  - HBase Shell for MapR-DB
    You can manage MapR-DB tables using HBase shell commands and additional HBase shell commands included in the MapR distribution of Hadoop.
  - YARN commands
  - maprcli and REST API Syntax
  - Alarms Reference
  - Utilities
  - Default MapR Configurations
  - Configuration Files
  - MapR Environment
  - MapR Parameters
  - Best Practices
  - Language Support for MapR-DB Tables
  - Glossary
    This section contains defintions for commonly used terms in MapR Converged Data Platform environments.
  - Source Code for MapR Software
- Glossary
  This section contains defintions for commonly used terms in MapR Converged Data Platform environments.

Hadoop Commands

All Hadoop commands are invoked by the bin/hadoop script.

When you run these commands, you can specify the MapReduce mode in two different ways:

Use the hadoop keyword and specify the mode explicitly, where classic mode refers to Hadoop 1.x and yarn mode refers to Hadoop 2.x.
Use the hadoop1 or hadoop2 keyword and do not specify the mode.

For example, the following commands are equivalent:

root@testnode100:/opt/mapr/conf/conf.d# hadoop2 conf | grep mapreduce.map.memory.mb
<property><name>mapreduce.map.memory.mb</name><value>1024</value></property>

root@testnode100:/opt/mapr/conf/conf.d# hadoop -yarn conf | grep mapreduce.map.memory.mb
<property><name>mapreduce.map.memory.mb</name><value>1024</value></property>