All mapreduce commands are invoked by the bin/mapred script. Running the mapred script without any arguments prints the description for all commands.
Usage: mapred [SHELL_OPTIONS] COMMAND [GENERIC_OPTIONS] [COMMAND_OPTIONS]
Hadoop has an option parsing framework that employs parsing generic options as well as running classes.
|SHELL_OPTIONS||The common set of shell options. These are documented on the Hadoop Commands Reference page.|
|GENERIC_OPTIONS||The common set of options supported by multiple commands. See the Hadoop Commands Reference for more information.|
|COMMAND COMMAND_OPTIONS||Various commands with their options are described in the following sections. The commands have been grouped into User Commands and Administration Commands.|
Commands useful for users of a hadoop cluster.
Creates a hadoop archive. More information can be found at Hadoop Archives Guide.
Prints the class path needed to get the Hadoop jar and the required libraries.
Usage: mapred classpath
Copy file or directories recursively. More information can be found at Hadoop DistCp Guide.
Command to interact with Map Reduce Jobs.
Usage: mapred job | [GENERIC_OPTIONS] | [-submit <job-file>] | [-status <job-id>] | [-counter <job-id> <group-name> <counter-name>] | [-kill <job-id>] | [-events <job-id> <from-event-#> <#-of-events>] | [-history [all] <jobOutputDir>] | [-list [all]] | [-kill-task <task-id>] | [-fail-task <task-id>] | [-set-priority <job-id> <priority>]
|-submit job-file||Submits the job.|
|-status job-id||Prints the map and reduce completion percentage and all job counters.|
|-counter job-id group-name counter-name||Prints the counter value.|
|-kill job-id||Kills the job.|
|-events job-id from-event-# #-of-events||Prints the events’ details received by jobtracker for the given range.|
|-history [all]jobOutputDir||Prints job details, failed and killed tip details. More details about the job such as successful tasks and task attempts made for each task can be viewed by specifying the [all] option.|
|-list [all]||Displays jobs which are yet to complete. -list all displays all jobs.|
|-kill-task task-id||Kills the task. Killed tasks are NOT counted against failed attempts.|
|-fail-task task-id||Fails the task. Failed tasks are counted against failed attempts.|
|-set-priority job-id priority||Changes the priority of the job. Allowed priority values are VERY_HIGH, HIGH, NORMAL, LOW, VERY_LOW|
Runs a pipes job.
Usage: mapred pipes [-conf <path>] [-jobconf <key=value>, <key=value>, ...] [-input <path>] [-output <path>] [-jar <jar file>] [-inputformat <class>] [-map <class>] [-partitioner <class>] [-reduce <class>] [-writer <class>] [-program <executable>] [-reduces <num>]
|-conf path||Configuration for job|
|-jobconf key=value, key=value, …||Add/override configuration for job|
|-input path||Input directory|
|-output path||Output directory|
|-jar jar file||Jar filename|
|-inputformat class||InputFormat class|
|-map class||Java Map class|
|-partitioner class||Java Partitioner|
|-reduce class||Java Reduce class|
|-writer class||Java RecordWriter|
|-program executable||Executable URI|
|-reduces num||Number of reduces|
command to interact and view Job Queue information
Usage: mapred queue [-list] | [-info <job-queue-name> [-showJobs]] | [-showacls]
|-list||Gets list of Job Queues configured in the system. Along with scheduling information associated with the job queues.|
|-info job-queue-name [-showJobs]||Displays the job queue information and associated scheduling information of particular job queue. If -showJobs options is present a list of jobs submitted to the particular job queue is displayed.|
|-showacls||Displays the queue name and associated queue operations allowed for the current user. The list consists of only those queues to which the user has access.|
Commands useful for administrators of a hadoop cluster.
Runs a MapReduce hsadmin client for execute JobHistoryServer administrative commands.
Usage: mapred hsadmin [-refreshUserToGroupsMappings] | [-refreshSuperUserGroupsConfiguration] | [-refreshAdminAcls] | [-refreshLoadedJobCache] | [-refreshLogRetentionSettings] | [-refreshJobRetentionSettings] | [-getGroups [username]] | [-help [cmd]]
|-refreshUserToGroupsMappings||Refresh user-to-groups mappings|
|-refreshSuperUserGroupsConfiguration||Refresh superuser proxy groups mappings|
|-refreshAdminAcls||Refresh acls for administration of Job history server|
|-refreshLoadedJobCache||Refresh loaded job cache of Job history server|
|-refreshJobRetentionSettings||Refresh job history period, job cleaner settings|
|-refreshLogRetentionSettings||Refresh log retention period and log retention check interval|
|-getGroups [username]||Get the groups which given user belongs to|
|-help [cmd]||Displays help for the given command or all commands if none is specified.|