Hadoop configuration parameters

Default: /tmp/hadoop-${user.name}

The number of Reduce Tasks for a MapReduce job.

Set to true to enable uber jobs.

uber jobs will be used only if the number of mappers is less or equal to the value of mapreduce.job.ubertask.maxmaps.

Default: 9

uber jobs will be used only if the number of reducers is less or equal to the value of mapreduce.job.ubertask.maxreduces.

Default: 1

uber jobs will be used only if the size of data of a job is less than the value of value of mapreduce.job.ubertask.maxbytes.

Default: default block size

Specifies how full a Mapper's circular buffer must become in order to start a MapReduce's Spilling phase.

Whether log file aggregation is enabled or not.

Default: false.

Number of seconds after an application finishes before the nodemanager's Deletion Service will delete the application's localized file directory and log directory.

See also yarn.nodemanager.log.retain-seconds

Default: ${hadoop.tmp.dir}/nm-local-dir

If, and how, aggregated logs should be compressed.

Possible values: none, lzo and gzip.

Default: none

Specifies the directory into which container log files are written.

Default: ${yarn.log.dir}/userlogs

How long, in seconds, user log files should be retained.

Only applicable if log aggregation is disabled.

See also #yarn-nodemanager.delete.debug-delay-sec

Default value: /tmp/logs

Default value: logs

Amount of physical memory allocatable for all containers managed by a node manager, in MB.

Default: 8192

The hostname of the resource manager.

Default: 0.0.0.0

The HTTP address of the resource manager web application.

Default: ${yarn.resourcemanager.hostname}:8088

Minimum amount of memory, in MB, a container allocets when requested from the resource manager.

Default: 1024

YARN configuration

https://hadoop.apache.org/docs/r2.6.0/hadoop-project-dist/hadoop-common/core-default.xml