--config confdir
Overwrites the default Configuration directory. Default is $HADOOP_HOME/conf.
GENERIC_OPTIONS COMMAND_OPTIONS
The common set of options supported by multiple commands. Various commands with their options are described in the following sections. The commands have been grouped into User Commands and Administration Commands.
通用选项
dfsadmin, fs, fsck, job and fetchdt都支持下属选项所有的。应用程序需要实现Tool接口然后才能支持通用选项解析。
GENERIC_OPTION
Description
-conf <configuration file>
Specify an application configuration file.
-D <property>=<value>
Use value for given property.
-jt <local> or <jobtracker:port>
Specify a job tracker. Applies only to job.
-files <comma separated list of files>
Specify comma separated files to be copied to the map reduce cluster. Applies only to job.
-libjars <comma seperated list of jars>
Specify comma separated jar files to include in the classpath. Applies only to job.
-archives <comma separated list of archives>
Specify comma separated archives to be unarchived on the compute machines. Applies only to job.
用户命令
hadoop集群用户基于命令是非常方便的。 archive:
创建一个hadoop归档,更多信息可以在hadoop归档中查找。
用法:hadoop archive -archiveName NAME <src>* <dest>
COMMAND_OPTION
Description
-archiveName NAME
Name of the archive to be created.
src
Filesystem pathnames which work as usual with regular expressions.
dest
Destination directory which would contain the archive. distcp:
循环拷贝文件和目录,详情可以在hadoop的DistCp 指南中查看。
用法:hadoop distcp <srcurl> <desturl>
Prints the map and reduce completion percentage and all job counters.
-counter job-idgroup-namecounter-name
Prints the counter value.
-kill job-id
Kills the job.
-events job-idfrom-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-idpriority
Changes the priority of the job. Allowed priority values are VERY_HIGH, HIGH, NORMAL, LOW, VERY_LOW
-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.
Prints the log level of the daemon running at host:port. This command internally connects to http://host:port/logLevel?log=name
-setlevel host:portnamelevel
Sets the log level of the daemon running at host:port. This command internally connects to http://host:port/logLevel?log=name
datanode:
启动一个datanode,用法如下:
hadoop datanode [-rollback]
COMMAND_OPTION
Description
-rollback
Rollsback the datanode to the previous version. This should be used after stopping the datanode and distributing the old hadoop version. dfsadmin :
启动一个hdfs 管理客户端,用法如下:
-report
Reports basic filesystem information and statistics.
-safemode enter / leave / get / wait
Safe mode maintenance command. Safe mode is a Namenode state in which it
1. does not accept changes to the name space (read-only)
2. does not replicate or delete blocks.
Safe mode is entered automatically at Namenode startup, and leaves safe mode automatically when the configured minimum percentage of blocks satisfies the minimum replication condition. Safe mode can also be entered manually, but then it can only be turned off manually as well.
-refreshNodes
Re-read the hosts and exclude files to update the set of Datanodes that are allowed to connect to the Namenode and those that should be decommissioned or recommissioned.
-finalizeUpgrade
Finalize upgrade of HDFS. Datanodes delete their previous version working directories, followed by Namenode doing the same. This completes the upgrade process.
-upgradeProgress status / details / force
Request current distributed upgrade status, a detailed status or force the upgrade to proceed.
-metasave filename
Save Namenode's primary data structures to filename in the directory specified by hadoop.log.dir property. filename is overwritten if it exists. filename will contain one line for each of the following
1. Datanodes heart beating with Namenode
2. Blocks waiting to be replicated
3. Blocks currrently being replicated
4. Blocks waiting to be deleted
-setQuota quotadirname...dirname
Set the quota quota for each directory dirname. The directory quota is a long integer that puts a hard limit on the number of names in the directory tree. Best effort for the directory, with faults reported if
1. N is not a positive integer, or
2. user is not an administrator, or
3. the directory does not exist or is a file, or
4. the directory would immediately exceed the new quota.
-clrQuotadirname...dirname
Clear the quota for each directory dirname. Best effort for the directory. with fault reported if
1. the directory does not exist or is a file, or
2. user is not an administrator. It does not fault if the directory has no quota.
-restoreFailedStorage true / false / check
This option will turn on/off automatic attempt to restore failed storage replicas. If a failed storage becomes available again the system will attempt to restore edits and/or fsimage during checkpoint. 'check' option will return current setting.
-help [cmd]
Displays help for the given command or all commands if none is specified. mradmin:
运行一个mr管理客户端,用法如下:
-refreshQueueAcls
Refresh the queue acls used by hadoop, to check access during submissions and administration of the job by the user. The properties present in mapred-queue-acls.xml is reloaded by the queue manager.
jobtracker:
运行一个MapReduce job tracker用法如下:
hadoop jobtracker [-dumpConfiguration]
COMMAND_OPTION
Description
-dumpConfiguration
Dumps the configuration used by the JobTracker alongwith queue configuration in JSON format into Standard output used by the jobtracker and exits. namenode:
运行以namenode用法如下:
-format
Formats the namenode. It starts the namenode, formats it and then shut it down.
-upgrade
Namenode should be started with upgrade option after the distribution of new hadoop version.
-rollback
Rollsback the namenode to the previous version. This should be used after stopping the cluster and distributing the old hadoop version.
-finalize
Finalize will remove the previous state of the files system. Recent upgrade will become permanent. Rollback option will not be available anymore. After finalization it shuts the namenode down.
-importCheckpoint
Loads image from a checkpoint directory and save it into the current one. Checkpoint dir is read from property fs.checkpoint.dir secondarynamenode:
运行一个hdfs的secondary namenode用法如下:
-checkpoint [-force]
Checkpoints the Secondary namenode if EditLog size >= fs.checkpoint.size. If -force is used, checkpoint irrespective of EditLog size.
-geteditsize
Prints the EditLog size. tasktracker:
运行一个mr的tasktracker节点,用法如下: