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MapReduce History Server REST API's.
====================================

* [MapReduce History Server REST API's.](#MapReduce_History_Server_REST_APIs.)
    * [Overview](#Overview)
    * [History Server Information API](#History_Server_Information_API)
        * [URI](#URI)
        * [HTTP Operations Supported](#HTTP_Operations_Supported)
        * [Query Parameters Supported](#Query_Parameters_Supported)
        * [Elements of the historyInfo object](#Elements_of_the_historyInfo_object)
        * [Response Examples](#Response_Examples)
    * [MapReduce API's](#MapReduce_APIs)
        * [Jobs API](#Jobs_API)
        * [Job API](#Job_API)
        * [Elements of the acls object](#Elements_of_the_acls_object)
        * [Job Attempts API](#Job_Attempts_API)
        * [Job Counters API](#Job_Counters_API)
        * [Job Conf API](#Job_Conf_API)
        * [Tasks API](#Tasks_API)
        * [Task API](#Task_API)
        * [Task Counters API](#Task_Counters_API)
        * [Task Attempts API](#Task_Attempts_API)
        * [Task Attempt API](#Task_Attempt_API)
        * [Task Attempt Counters API](#Task_Attempt_Counters_API)

Overview
--------

The history server REST API's allow the user to get status on finished applications.

History Server Information API
------------------------------

The history server information resource provides overall information about the history server.

### URI

Both of the following URI's give you the history server information, from an application id identified by the appid value.

      * http://<history server http address:port>/ws/v1/history
      * http://<history server http address:port>/ws/v1/history/info

### HTTP Operations Supported

      * GET

### Query Parameters Supported

      None

### Elements of the *historyInfo* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| startedOn | long | The time the history server was started (in ms since epoch) |
| hadoopVersion | string | Version of hadoop common |
| hadoopBuildVersion | string | Hadoop common build string with build version, user, and checksum |
| hadoopVersionBuiltOn | string | Timestamp when hadoop common was built |

### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/info

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {   
       "historyInfo" : {
          "startedOn":1353512830963,
          "hadoopVersionBuiltOn" : "Wed Jan 11 21:18:36 UTC 2012",
          "hadoopBuildVersion" : "0.23.1-SNAPSHOT from 1230253 by user1 source checksum bb6e554c6d50b0397d826081017437a7",
          "hadoopVersion" : "0.23.1-SNAPSHOT"
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/info
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 330
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <historyInfo>
      <startedOn>1353512830963</startedOn>
      <hadoopVersion>0.23.1-SNAPSHOT</hadoopVersion>
      <hadoopBuildVersion>0.23.1-SNAPSHOT from 1230253 by user1 source checksum bb6e554c6d50b0397d826081017437a7</hadoopBuildVersion>
      <hadoopVersionBuiltOn>Wed Jan 11 21:18:36 UTC 2012</hadoopVersionBuiltOn>
    </historyInfo>

MapReduce API's
---------------

The following list of resources apply to MapReduce.

### Jobs API

The jobs resource provides a list of the MapReduce jobs that have finished. It does not currently return a full list of parameters

#### URI

      *  http://<history server http address:port>/ws/v1/history/mapreduce/jobs

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

Multiple paramters can be specified. The started and finished times have a begin and end parameter to allow you to specify ranges. For example, one could request all jobs that started between 1:00am and 2:00pm on 12/19/2011 with startedTimeBegin=1324256400&startedTimeEnd=1324303200. If the Begin parameter is not specfied, it defaults to 0, and if the End parameter is not specified, it defaults to infinity.

      * user - user name
      * state - the job state
      * queue - queue name
      * limit - total number of app objects to be returned
      * startedTimeBegin - jobs with start time beginning with this time, specified in ms since epoch
      * startedTimeEnd - jobs with start time ending with this time, specified in ms since epoch
      * finishedTimeBegin - jobs with finish time beginning with this time, specified in ms since epoch
      * finishedTimeEnd - jobs with finish time ending with this time, specified in ms since epoch

#### Elements of the *jobs* object

When you make a request for the list of jobs, the information will be returned as an array of job objects. See also
[Job API](#Job_API)
for syntax of the job object. Except this is a subset of a full job. Only startTime, finishTime, id, name, queue, user, state, mapsTotal, mapsCompleted, reducesTotal, and reducesCompleted are returned.

| Item | Data Type | Description |
|:---- |:---- |:---- |
| job | array of job objects(json)/zero or more job objects(XML) | The collection of job objects |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {
       "jobs" : {
          "job" : [
             {
                "submitTime" : 1326381344449,
                "state" : "SUCCEEDED",
                "user" : "user1",
                "reducesTotal" : 1,
                "mapsCompleted" : 1,
                "startTime" : 1326381344489,
                "id" : "job_1326381300833_1_1",
                "name" : "word count",
                "reducesCompleted" : 1,
                "mapsTotal" : 1,
                "queue" : "default",
                "finishTime" : 1326381356010
             },
             {
                "submitTime" : 1326381446500
                "state" : "SUCCEEDED",
                "user" : "user1",
                "reducesTotal" : 1,
                "mapsCompleted" : 1,
                "startTime" : 1326381446529,
                "id" : "job_1326381300833_2_2",
                "name" : "Sleep job",
                "reducesCompleted" : 1,
                "mapsTotal" : 1,
                "queue" : "default",
                "finishTime" : 1326381582106
             }
          ]
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 1922
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <jobs>
      <job>
        <submitTime>1326381344449</submitTime>
        <startTime>1326381344489</startTime>
        <finishTime>1326381356010</finishTime>
        <id>job_1326381300833_1_1</id>
        <name>word count</name>
        <queue>default</queue>
        <user>user1</user>
        <state>SUCCEEDED</state>
        <mapsTotal>1</mapsTotal>
        <mapsCompleted>1</mapsCompleted>
        <reducesTotal>1</reducesTotal>
        <reducesCompleted>1</reducesCompleted>
      </job>
      <job>
        <submitTime>1326381446500</submitTime>
        <startTime>1326381446529</startTime>
        <finishTime>1326381582106</finishTime>
        <id>job_1326381300833_2_2</id>
        <name>Sleep job</name>
        <queue>default</queue>
        <user>user1</user>
        <state>SUCCEEDED</state>
        <mapsTotal>1</mapsTotal>
        <mapsCompleted>1</mapsCompleted>
        <reducesTotal>1</reducesTotal>
        <reducesCompleted>1</reducesCompleted>
      </job>
    </jobs>

### Job API

A Job resource contains information about a particular job identified by jobid.

#### URI

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      None

#### Elements of the *job* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| id | string | The job id |
| name | string | The job name |
| queue | string | The queue the job was submitted to |
| user | string | The user name |
| state | string | the job state - valid values are: NEW, INITED, RUNNING, SUCCEEDED, FAILED, KILL\_WAIT, KILLED, ERROR |
| diagnostics | string | A diagnostic message |
| submitTime | long | The time the job submitted (in ms since epoch) |
| startTime | long | The time the job started (in ms since epoch) |
| finishTime | long | The time the job finished (in ms since epoch) |
| mapsTotal | int | The total number of maps |
| mapsCompleted | int | The number of completed maps |
| reducesTotal | int | The total number of reduces |
| reducesCompleted | int | The number of completed reduces |
| uberized | boolean | Indicates if the job was an uber job - ran completely in the application master |
| avgMapTime | long | The average time of a map task (in ms) |
| avgReduceTime | long | The average time of the reduce (in ms) |
| avgShuffleTime | long | The average time of the shuffle (in ms) |
| avgMergeTime | long | The average time of the merge (in ms) |
| failedReduceAttempts | int | The number of failed reduce attempts |
| killedReduceAttempts | int | The number of killed reduce attempts |
| successfulReduceAttempts | int | The number of successful reduce attempts |
| failedMapAttempts | int | The number of failed map attempts |
| killedMapAttempts | int | The number of killed map attempts |
| successfulMapAttempts | int | The number of successful map attempts |
| acls | array of acls(json)/zero or more acls objects(xml) | A collection of acls objects |

### Elements of the *acls* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| value | string | The acl value |
| name | string | The acl name |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Server: Jetty(6.1.26)
      Content-Length: 720

Response Body:

    {
       "job" : {
          "submitTime":  1326381446500,
          "avgReduceTime" : 124961,
          "failedReduceAttempts" : 0,
          "state" : "SUCCEEDED",
          "successfulReduceAttempts" : 1,
          "acls" : [
             {
                "value" : " ",
                "name" : "mapreduce.job.acl-modify-job"
             },
             {
                "value" : " ",
                "name" : "mapreduce.job.acl-view-job"
             }
          ],
          "user" : "user1",
          "reducesTotal" : 1,
          "mapsCompleted" : 1,
          "startTime" : 1326381446529,
          "id" : "job_1326381300833_2_2",
          "avgMapTime" : 2638,
          "successfulMapAttempts" : 1,
          "name" : "Sleep job",
          "avgShuffleTime" : 2540,
          "reducesCompleted" : 1,
          "diagnostics" : "",
          "failedMapAttempts" : 0,
          "avgMergeTime" : 2589,
          "killedReduceAttempts" : 0,
          "mapsTotal" : 1,
          "queue" : "default",
          "uberized" : false,
          "killedMapAttempts" : 0,
          "finishTime" : 1326381582106
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 983
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <job>
      <submitTime>1326381446500</submitTime>
      <startTime>1326381446529</startTime>
      <finishTime>1326381582106</finishTime>
      <id>job_1326381300833_2_2</id>
      <name>Sleep job</name>
      <queue>default</queue>
      <user>user1</user>
      <state>SUCCEEDED</state>
      <mapsTotal>1</mapsTotal>
      <mapsCompleted>1</mapsCompleted>
      <reducesTotal>1</reducesTotal>
      <reducesCompleted>1</reducesCompleted>
      <uberized>false</uberized>
      <diagnostics/>
      <avgMapTime>2638</avgMapTime>
      <avgReduceTime>124961</avgReduceTime>
      <avgShuffleTime>2540</avgShuffleTime>
      <avgMergeTime>2589</avgMergeTime>
      <failedReduceAttempts>0</failedReduceAttempts>
      <killedReduceAttempts>0</killedReduceAttempts>
      <successfulReduceAttempts>1</successfulReduceAttempts>
      <failedMapAttempts>0</failedMapAttempts>
      <killedMapAttempts>0</killedMapAttempts>
      <successfulMapAttempts>1</successfulMapAttempts>
      <acls>
        <name>mapreduce.job.acl-modify-job</name>
        <value> </value>
      </acls>
      <acls>
        <name>mapreduce.job.acl-view-job</name>
        <value> </value>
      </acls>
    </job>

### Job Attempts API

With the job attempts API, you can obtain a collection of resources that represent a job attempt. When you run a GET operation on this resource, you obtain a collection of Job Attempt Objects.

#### URI

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/jobattempts

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      None

#### Elements of the *jobAttempts* object

When you make a request for the list of job attempts, the information will be returned as an array of job attempt objects.

jobAttempts:

| Item | Data Type | Description |
|:---- |:---- |:---- |
| jobAttempt | array of job attempt objects(JSON)/zero or more job attempt objects(XML) | The collection of job attempt objects |

#### Elements of the *jobAttempt* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| id | string | The job attempt id |
| nodeId | string | The node id of the node the attempt ran on |
| nodeHttpAddress | string | The node http address of the node the attempt ran on |
| logsLink | string | The http link to the job attempt logs |
| containerId | string | The id of the container for the job attempt |
| startTime | long | The start time of the attempt (in ms since epoch) |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/jobattempts

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {
       "jobAttempts" : {
          "jobAttempt" : [
             {
                "nodeId" : "host.domain.com:8041",
                "nodeHttpAddress" : "host.domain.com:8042",
                "startTime" : 1326381444693,
                "id" : 1,
                "logsLink" : "http://host.domain.com:19888/jobhistory/logs/host.domain.com:8041/container_1326381300833_0002_01_000001/job_1326381300833_2_2/user1",
                "containerId" : "container_1326381300833_0002_01_000001"
             }
          ]
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/jobattmpts
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 575
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <jobAttempts>
      <jobAttempt>
        <nodeHttpAddress>host.domain.com:8042</nodeHttpAddress>
        <nodeId>host.domain.com:8041</nodeId>
        <id>1</id>
        <startTime>1326381444693</startTime>
        <containerId>container_1326381300833_0002_01_000001</containerId>
        <logsLink>http://host.domain.com:19888/jobhistory/logs/host.domain.com:8041/container_1326381300833_0002_01_000001/job_1326381300833_2_2/user1</logsLink>
      </jobAttempt>
    </jobAttempts>

### Job Counters API

With the job counters API, you can object a collection of resources that represent al the counters for that job.

#### URI

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/counters

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      None

#### Elements of the *jobCounters* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| id | string | The job id |
| counterGroup | array of counterGroup objects(JSON)/zero or more counterGroup objects(XML) | A collection of counter group objects |

#### Elements of the *counterGroup* objecs

| Item | Data Type | Description |
|:---- |:---- |:---- |
| counterGroupName | string | The name of the counter group |
| counter | array of counter objects(JSON)/zero or more counter objects(XML) | A collection of counter objects |

#### Elements of the *counter* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| name | string | The name of the counter |
| reduceCounterValue | long | The counter value of reduce tasks |
| mapCounterValue | long | The counter value of map tasks |
| totalCounterValue | long | The counter value of all tasks |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/counters

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {
       "jobCounters" : {
          "id" : "job_1326381300833_2_2",
          "counterGroup" : [
             {
                "counterGroupName" : "Shuffle Errors",
                "counter" : [
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "BAD_ID"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "CONNECTION"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "IO_ERROR"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "WRONG_LENGTH"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "WRONG_MAP"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "WRONG_REDUCE"
                   }
                ]
              },
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.FileSystemCounter",
                "counter" : [
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 2483,
                      "name" : "FILE_BYTES_READ"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 108525,
                      "name" : "FILE_BYTES_WRITTEN"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "FILE_READ_OPS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "FILE_LARGE_READ_OPS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "FILE_WRITE_OPS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 48,
                      "name" : "HDFS_BYTES_READ"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "HDFS_BYTES_WRITTEN"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 1,
                      "name" : "HDFS_READ_OPS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "HDFS_LARGE_READ_OPS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "HDFS_WRITE_OPS"
                   }
                ]
             },
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.TaskCounter",
                "counter" : [
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 1,
                      "name" : "MAP_INPUT_RECORDS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 1200,
                      "name" : "MAP_OUTPUT_RECORDS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 4800,
                      "name" : "MAP_OUTPUT_BYTES"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 2235,
                      "name" : "MAP_OUTPUT_MATERIALIZED_BYTES"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 48,
                      "name" : "SPLIT_RAW_BYTES"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "COMBINE_INPUT_RECORDS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "COMBINE_OUTPUT_RECORDS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 1200,
                      "name" : "REDUCE_INPUT_GROUPS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 2235,
                      "name" : "REDUCE_SHUFFLE_BYTES"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 1200,
                      "name" : "REDUCE_INPUT_RECORDS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "REDUCE_OUTPUT_RECORDS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 2400,
                      "name" : "SPILLED_RECORDS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 1,
                      "name" : "SHUFFLED_MAPS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "FAILED_SHUFFLE"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 1,
                      "name" : "MERGED_MAP_OUTPUTS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 113,
                      "name" : "GC_TIME_MILLIS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 1830,
                      "name" : "CPU_MILLISECONDS"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 478068736,
                      "name" : "PHYSICAL_MEMORY_BYTES"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 2159284224,
                      "name" : "VIRTUAL_MEMORY_BYTES"
                   },
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 378863616,
                      "name" : "COMMITTED_HEAP_BYTES"
                   }
                ]
             },
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.lib.input.FileInputFormatCounter",
                "counter" : [
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "BYTES_READ"
                   }
                ]
             },
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.lib.output.FileOutputFormatCounter",
                "counter" : [
                   {
                      "reduceCounterValue" : 0,
                      "mapCounterValue" : 0,
                      "totalCounterValue" : 0,
                      "name" : "BYTES_WRITTEN"
                   }
                ]
             }
          ]
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/counters
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 7030
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <jobCounters>
      <id>job_1326381300833_2_2</id>
      <counterGroup>
        <counterGroupName>Shuffle Errors</counterGroupName>
        <counter>
          <name>BAD_ID</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>CONNECTION</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>IO_ERROR</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>WRONG_LENGTH</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>WRONG_MAP</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>WRONG_REDUCE</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
      </counterGroup>
      <counterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.FileSystemCounter</counterGroupName>
        <counter>
          <name>FILE_BYTES_READ</name>
          <totalCounterValue>2483</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>FILE_BYTES_WRITTEN</name>
          <totalCounterValue>108525</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>FILE_READ_OPS</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>FILE_LARGE_READ_OPS</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>FILE_WRITE_OPS</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>HDFS_BYTES_READ</name>
          <totalCounterValue>48</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>HDFS_BYTES_WRITTEN</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>HDFS_READ_OPS</name>
          <totalCounterValue>1</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>HDFS_LARGE_READ_OPS</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>HDFS_WRITE_OPS</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
      </counterGroup>
      <counterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.TaskCounter</counterGroupName>
        <counter>
          <name>MAP_INPUT_RECORDS</name>
          <totalCounterValue>1</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>MAP_OUTPUT_RECORDS</name>
          <totalCounterValue>1200</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>MAP_OUTPUT_BYTES</name>
          <totalCounterValue>4800</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>MAP_OUTPUT_MATERIALIZED_BYTES</name>
          <totalCounterValue>2235</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>SPLIT_RAW_BYTES</name>
          <totalCounterValue>48</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>COMBINE_INPUT_RECORDS</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>COMBINE_OUTPUT_RECORDS</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>REDUCE_INPUT_GROUPS</name>
          <totalCounterValue>1200</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>REDUCE_SHUFFLE_BYTES</name>
          <totalCounterValue>2235</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>REDUCE_INPUT_RECORDS</name>
          <totalCounterValue>1200</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>REDUCE_OUTPUT_RECORDS</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>SPILLED_RECORDS</name>
          <totalCounterValue>2400</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>SHUFFLED_MAPS</name>
          <totalCounterValue>1</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>FAILED_SHUFFLE</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>MERGED_MAP_OUTPUTS</name>
          <totalCounterValue>1</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>GC_TIME_MILLIS</name>
          <totalCounterValue>113</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>CPU_MILLISECONDS</name>
          <totalCounterValue>1830</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>PHYSICAL_MEMORY_BYTES</name>
          <totalCounterValue>478068736</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>VIRTUAL_MEMORY_BYTES</name>
          <totalCounterValue>2159284224</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
        <counter>
          <name>COMMITTED_HEAP_BYTES</name>
          <totalCounterValue>378863616</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
      </counterGroup>
      <counterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.lib.input.FileInputFormatCounter</counterGroupName>
        <counter>
          <name>BYTES_READ</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
      </counterGroup>
      <counterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.lib.output.FileOutputFormatCounter</counterGroupName>
        <counter>
          <name>BYTES_WRITTEN</name>
          <totalCounterValue>0</totalCounterValue>
          <mapCounterValue>0</mapCounterValue>
          <reduceCounterValue>0</reduceCounterValue>
        </counter>
      </counterGroup>
    </jobCounters>

### Job Conf API

A job configuration resource contains information about the job configuration for this job.

#### URI

Use the following URI to obtain th job configuration information, from a job identified by the jobid value.

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/conf

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      None

#### Elements of the *conf* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| path | string | The path to the job configuration file |
| property | array of the configuration properties(JSON)/zero or more configuration properties(XML) | Collection of configuration property objects |

#### Elements of the *property* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| name | string | The name of the configuration property |
| value | string | The value of the configuration property |
| source | string | The location this configuration object came from. If there is more then one of these it shows the history with the latest source at the end of the list. |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/conf

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

This is a small snippet of the output as the output if very large. The real output contains every property in your job configuration file.

    {
       "conf" : {
          "path" : "hdfs://host.domain.com:9000/user/user1/.staging/job_1326381300833_0002/job.xml",
          "property" : [
             {  
                "value" : "/home/hadoop/hdfs/data",
                "name" : "dfs.datanode.data.dir"
                "source" : ["hdfs-site.xml", "job.xml"]
             },
             {
                "value" : "org.apache.hadoop.yarn.server.webproxy.amfilter.AmFilterInitializer",
                "name" : "hadoop.http.filter.initializers"
                "source" : ["programmatically", "job.xml"]
             },
             {
                "value" : "/home/hadoop/tmp",
                "name" : "mapreduce.cluster.temp.dir"
                "source" : ["mapred-site.xml"]
             },
             ...
          ]
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/conf
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 552
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <conf>
      <path>hdfs://host.domain.com:9000/user/user1/.staging/job_1326381300833_0002/job.xml</path>
      <property>
        <name>dfs.datanode.data.dir</name>
        <value>/home/hadoop/hdfs/data</value>
        <source>hdfs-site.xml</source>
        <source>job.xml</source>
      </property>
      <property>
        <name>hadoop.http.filter.initializers</name>
        <value>org.apache.hadoop.yarn.server.webproxy.amfilter.AmFilterInitializer</value>
        <source>programmatically</source>
        <source>job.xml</source>
      </property>
      <property>
        <name>mapreduce.cluster.temp.dir</name>
        <value>/home/hadoop/tmp</value>
        <source>mapred-site.xml</source>
      </property>
      ...
    </conf>

### Tasks API

With the tasks API, you can obtain a collection of resources that represent a task within a job. When you run a GET operation on this resource, you obtain a collection of Task Objects.

#### URI

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/tasks

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      * type - type of task, valid values are m or r.  m for map task or r for reduce task.

#### Elements of the *tasks* object

When you make a request for the list of tasks , the information will be returned as an array of task objects. See also
[Task API](#Task_API)
for syntax of the task object.

| Item | Data Type | Description |
|:---- |:---- |:---- |
| task | array of task objects(JSON)/zero or more task objects(XML) | The collection of task objects. |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {
       "tasks" : {
          "task" : [
             {
                "progress" : 100,
                "elapsedTime" : 6777,
                "state" : "SUCCEEDED",
                "startTime" : 1326381446541,
                "id" : "task_1326381300833_2_2_m_0",
                "type" : "MAP",
                "successfulAttempt" : "attempt_1326381300833_2_2_m_0_0",
                "finishTime" : 1326381453318
             },
             {
                "progress" : 100,
                "elapsedTime" : 135559,
                "state" : "SUCCEEDED",
                "startTime" : 1326381446544,
                "id" : "task_1326381300833_2_2_r_0",
                "type" : "REDUCE",
                "successfulAttempt" : "attempt_1326381300833_2_2_r_0_0",
                "finishTime" : 1326381582103
             }
          ]
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 653
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <tasks>
      <task>
        <startTime>1326381446541</startTime>
        <finishTime>1326381453318</finishTime>
        <elapsedTime>6777</elapsedTime>
        <progress>100.0</progress>
        <id>task_1326381300833_2_2_m_0</id>
        <state>SUCCEEDED</state>
        <type>MAP</type>
        <successfulAttempt>attempt_1326381300833_2_2_m_0_0</successfulAttempt>
      </task>
      <task>
        <startTime>1326381446544</startTime>
        <finishTime>1326381582103</finishTime>
        <elapsedTime>135559</elapsedTime>
        <progress>100.0</progress>
        <id>task_1326381300833_2_2_r_0</id>
        <state>SUCCEEDED</state>
        <type>REDUCE</type>
        <successfulAttempt>attempt_1326381300833_2_2_r_0_0</successfulAttempt>
      </task>
    </tasks>

### Task API

A Task resource contains information about a particular task within a job.

#### URI

Use the following URI to obtain an Task Object, from a task identified by the taskid value.

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/tasks/{taskid}

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      None

#### Elements of the *task* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| id | string | The task id |
| state | string | The state of the task - valid values are: NEW, SCHEDULED, RUNNING, SUCCEEDED, FAILED, KILL\_WAIT, KILLED |
| type | string | The task type - MAP or REDUCE |
| successfulAttempt | string | The id of the last successful attempt |
| progress | float | The progress of the task as a percent |
| startTime | long | The time in which the task started (in ms since epoch) or -1 if it was never started |
| finishTime | long | The time in which the task finished (in ms since epoch) |
| elapsedTime | long | The elapsed time since the application started (in ms) |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {
       "task" : {
          "progress" : 100,
          "elapsedTime" : 6777,
          "state" : "SUCCEEDED",
          "startTime" : 1326381446541,
          "id" : "task_1326381300833_2_2_m_0",
          "type" : "MAP",
          "successfulAttempt" : "attempt_1326381300833_2_2_m_0_0",
          "finishTime" : 1326381453318
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 299
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <task>
      <startTime>1326381446541</startTime>
      <finishTime>1326381453318</finishTime>
      <elapsedTime>6777</elapsedTime>
      <progress>100.0</progress>
      <id>task_1326381300833_2_2_m_0</id>
      <state>SUCCEEDED</state>
      <type>MAP</type>
      <successfulAttempt>attempt_1326381300833_2_2_m_0_0</successfulAttempt>
    </task>

### Task Counters API

With the task counters API, you can object a collection of resources that represent all the counters for that task.

#### URI

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/tasks/{taskid}/counters

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      None

#### Elements of the *jobTaskCounters* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| id | string | The task id |
| taskcounterGroup | array of counterGroup objects(JSON)/zero or more counterGroup objects(XML) | A collection of counter group objects |

#### Elements of the *counterGroup* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| counterGroupName | string | The name of the counter group |
| counter | array of counter objects(JSON)/zero or more counter objects(XML) | A collection of counter objects |

#### Elements of the *counter* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| name | string | The name of the counter |
| value | long | The value of the counter |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0/counters

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {
       "jobTaskCounters" : {
          "id" : "task_1326381300833_2_2_m_0",
          "taskCounterGroup" : [
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.FileSystemCounter",
                "counter" : [
                   {
                      "value" : 2363,
                      "name" : "FILE_BYTES_READ"
                   },
                   {
                      "value" : 54372,
                      "name" : "FILE_BYTES_WRITTEN"
                   },
                   {
                      "value" : 0,
                      "name" : "FILE_READ_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "FILE_LARGE_READ_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "FILE_WRITE_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "HDFS_BYTES_READ"
                   },
                   {
                      "value" : 0,
                      "name" : "HDFS_BYTES_WRITTEN"
                   },
                   {
                      "value" : 0,
                      "name" : "HDFS_READ_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "HDFS_LARGE_READ_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "HDFS_WRITE_OPS"
                   }
                ]
             },
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.TaskCounter",
                "counter" : [
                   {
                      "value" : 0,
                      "name" : "COMBINE_INPUT_RECORDS"
                   },
                   {
                      "value" : 0,
                      "name" : "COMBINE_OUTPUT_RECORDS"
                   },
                   {
                      "value" : 460,
                      "name" : "REDUCE_INPUT_GROUPS"
                   },
                   {
                      "value" : 2235,
                      "name" : "REDUCE_SHUFFLE_BYTES"
                   },
                   {
                      "value" : 460,
                      "name" : "REDUCE_INPUT_RECORDS"
                   },
                   {
                      "value" : 0,
                      "name" : "REDUCE_OUTPUT_RECORDS"
                   },
                   {
                      "value" : 0,
                      "name" : "SPILLED_RECORDS"
                   },
                   {
                      "value" : 1,
                      "name" : "SHUFFLED_MAPS"
                   },
                   {
                      "value" : 0,
                      "name" : "FAILED_SHUFFLE"
                   },
                   {
                      "value" : 1,
                      "name" : "MERGED_MAP_OUTPUTS"
                   },
                   {
                      "value" : 26,
                      "name" : "GC_TIME_MILLIS"
                   },
                   {
                      "value" : 860,
                      "name" : "CPU_MILLISECONDS"
                   },
                   {
                      "value" : 107839488,
                      "name" : "PHYSICAL_MEMORY_BYTES"
                   },
                   {
                      "value" : 1123147776,
                      "name" : "VIRTUAL_MEMORY_BYTES"
                   },
                   {
                      "value" : 57475072,
                      "name" : "COMMITTED_HEAP_BYTES"
                   }
                ]
             },
             {
                "counterGroupName" : "Shuffle Errors",
                "counter" : [
                   {
                      "value" : 0,
                      "name" : "BAD_ID"
                   },
                   {
                      "value" : 0,
                      "name" : "CONNECTION"
                   },
                   {
                      "value" : 0,
                      "name" : "IO_ERROR"
                   },
                   {
                      "value" : 0,
                      "name" : "WRONG_LENGTH"
                   },
                   {
                      "value" : 0,
                      "name" : "WRONG_MAP"
                   },
                   {
                      "value" : 0,
                      "name" : "WRONG_REDUCE"
                   }
                ]
             },
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.lib.output.FileOutputFormatCounter",
                "counter" : [
                   {
                      "value" : 0,
                      "name" : "BYTES_WRITTEN"
                   }
                ]
             }
          ]
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0/counters
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 2660
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <jobTaskCounters>
      <id>task_1326381300833_2_2_m_0</id>
      <taskCounterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.FileSystemCounter</counterGroupName>
        <counter>
          <name>FILE_BYTES_READ</name>
          <value>2363</value>
        </counter>
        <counter>
          <name>FILE_BYTES_WRITTEN</name>
          <value>54372</value>
        </counter>
        <counter>
          <name>FILE_READ_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>FILE_LARGE_READ_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>FILE_WRITE_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_BYTES_READ</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_BYTES_WRITTEN</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_READ_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_LARGE_READ_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_WRITE_OPS</name>
          <value>0</value>
        </counter>
      </taskCounterGroup>
      <taskCounterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.TaskCounter</counterGroupName>
        <counter>
          <name>COMBINE_INPUT_RECORDS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>COMBINE_OUTPUT_RECORDS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>REDUCE_INPUT_GROUPS</name>
          <value>460</value>
        </counter>
        <counter>
          <name>REDUCE_SHUFFLE_BYTES</name>
          <value>2235</value>
        </counter>
        <counter>
          <name>REDUCE_INPUT_RECORDS</name>
          <value>460</value>
        </counter>
        <counter>
          <name>REDUCE_OUTPUT_RECORDS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>SPILLED_RECORDS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>SHUFFLED_MAPS</name>
          <value>1</value>
        </counter>
        <counter>
          <name>FAILED_SHUFFLE</name>
          <value>0</value>
        </counter>
        <counter>
          <name>MERGED_MAP_OUTPUTS</name>
          <value>1</value>
        </counter>
        <counter>
          <name>GC_TIME_MILLIS</name>
          <value>26</value>
        </counter>
        <counter>
          <name>CPU_MILLISECONDS</name>
          <value>860</value>
        </counter>
        <counter>
          <name>PHYSICAL_MEMORY_BYTES</name>
          <value>107839488</value>
        </counter>
        <counter>
          <name>VIRTUAL_MEMORY_BYTES</name>
          <value>1123147776</value>
        </counter>
        <counter>
          <name>COMMITTED_HEAP_BYTES</name>
          <value>57475072</value>
        </counter>
      </taskCounterGroup>
      <taskCounterGroup>
        <counterGroupName>Shuffle Errors</counterGroupName>
        <counter>
          <name>BAD_ID</name>
          <value>0</value>
        </counter>
        <counter>
          <name>CONNECTION</name>
          <value>0</value>
        </counter>
        <counter>
          <name>IO_ERROR</name>
          <value>0</value>
        </counter>
        <counter>
          <name>WRONG_LENGTH</name>
          <value>0</value>
        </counter>
        <counter>
          <name>WRONG_MAP</name>
          <value>0</value>
        </counter>
        <counter>
          <name>WRONG_REDUCE</name>
          <value>0</value>
        </counter>
      </taskCounterGroup>
      <taskCounterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.lib.output.FileOutputFormatCounter</counterGroupName>
        <counter>
          <name>BYTES_WRITTEN</name>
          <value>0</value>
        </counter>
      </taskCounterGroup>
    </jobTaskCounters>

### Task Attempts API

With the task attempts API, you can obtain a collection of resources that represent a task attempt within a job. When you run a GET operation on this resource, you obtain a collection of Task Attempt Objects.

#### URI

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/tasks/{taskid}/attempts

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      None

#### Elements of the *taskAttempts* object

When you make a request for the list of task attempts, the information will be returned as an array of task attempt objects. See also
[Task Attempt API](#Task_Attempt_API)
for syntax of the task object.

| Item | Data Type | Description |
|:---- |:---- |:---- |
| taskAttempt | array of task attempt objects(JSON)/zero or more task attempt objects(XML) | The collection of task attempt objects |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0/attempts

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {
       "taskAttempts" : {
          "taskAttempt" : [
             {
                "assignedContainerId" : "container_1326381300833_0002_01_000002",
                "progress" : 100,
                "elapsedTime" : 2638,
                "state" : "SUCCEEDED",
                "diagnostics" : "",
                "rack" : "/98.139.92.0",
                "nodeHttpAddress" : "host.domain.com:8042",
                "startTime" : 1326381450680,
                "id" : "attempt_1326381300833_2_2_m_0_0",
                "type" : "MAP",
                "finishTime" : 1326381453318
             }
          ]
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0/attempts
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 537
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <taskAttempts>
      <taskAttempt>
        <startTime>1326381450680</startTime>
        <finishTime>1326381453318</finishTime>
        <elapsedTime>2638</elapsedTime>
        <progress>100.0</progress>
        <id>attempt_1326381300833_2_2_m_0_0</id>
        <rack>/98.139.92.0</rack>
        <state>SUCCEEDED</state>
        <nodeHttpAddress>host.domain.com:8042</nodeHttpAddress>
        <diagnostics/>
        <type>MAP</type>
        <assignedContainerId>container_1326381300833_0002_01_000002</assignedContainerId>
      </taskAttempt>
    </taskAttempts>

### Task Attempt API

A Task Attempt resource contains information about a particular task attempt within a job.

#### URI

Use the following URI to obtain an Task Attempt Object, from a task identified by the attemptid value.

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/tasks/{taskid}/attempts/{attemptid}

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      None

#### Elements of the *taskAttempt* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| id | string | The task id |
| rack | string | The rack |
| state | string | The state of the task attempt - valid values are: NEW, UNASSIGNED, ASSIGNED, RUNNING, COMMIT\_PENDING, SUCCESS\_CONTAINER\_CLEANUP, SUCCEEDED, FAIL\_CONTAINER\_CLEANUP, FAIL\_TASK\_CLEANUP, FAILED, KILL\_CONTAINER\_CLEANUP, KILL\_TASK\_CLEANUP, KILLED |
| type | string | The type of task |
| assignedContainerId | string | The container id this attempt is assigned to |
| nodeHttpAddress | string | The http address of the node this task attempt ran on |
| diagnostics | string | A diagnostics message |
| progress | float | The progress of the task attempt as a percent |
| startTime | long | The time in which the task attempt started (in ms since epoch) |
| finishTime | long | The time in which the task attempt finished (in ms since epoch) |
| elapsedTime | long | The elapsed time since the task attempt started (in ms) |

For reduce task attempts you also have the following fields:

| Item | Data Type | Description |
|:---- |:---- |:---- |
| shuffleFinishTime | long | The time at which shuffle finished (in ms since epoch) |
| mergeFinishTime | long | The time at which merge finished (in ms since epoch) |
| elapsedShuffleTime | long | The time it took for the shuffle phase to complete (time in ms between reduce task start and shuffle finish) |
| elapsedMergeTime | long | The time it took for the merge phase to complete (time in ms between the shuffle finish and merge finish) |
| elapsedReduceTime | long | The time it took for the reduce phase to complete (time in ms between merge finish to end of reduce task) |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0/attempts/attempt_1326381300833_2_2_m_0_0 

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {
       "taskAttempt" : {
          "assignedContainerId" : "container_1326381300833_0002_01_000002",
          "progress" : 100,
          "elapsedTime" : 2638,
          "state" : "SUCCEEDED",
          "diagnostics" : "",
          "rack" : "/98.139.92.0",
          "nodeHttpAddress" : "host.domain.com:8042",
          "startTime" : 1326381450680,
          "id" : "attempt_1326381300833_2_2_m_0_0",
          "type" : "MAP",
          "finishTime" : 1326381453318
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0/attempts/attempt_1326381300833_2_2_m_0_0 
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 691
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <taskAttempt>
      <startTime>1326381450680</startTime>
      <finishTime>1326381453318</finishTime>
      <elapsedTime>2638</elapsedTime>
      <progress>100.0</progress>
      <id>attempt_1326381300833_2_2_m_0_0</id>
      <rack>/98.139.92.0</rack>
      <state>SUCCEEDED</state>
      <nodeHttpAddress>host.domain.com:8042</nodeHttpAddress>
      <diagnostics/>
      <type>MAP</type>
      <assignedContainerId>container_1326381300833_0002_01_000002</assignedContainerId>
    </taskAttempt>

### Task Attempt Counters API

With the task attempt counters API, you can object a collection of resources that represent al the counters for that task attempt.

#### URI

      * http://<history server http address:port>/ws/v1/history/mapreduce/jobs/{jobid}/tasks/{taskid}/attempts/{attemptid}/counters

#### HTTP Operations Supported

      * GET

#### Query Parameters Supported

      None

#### Elements of the *jobTaskAttemptCounters* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| id | string | The task attempt id |
| taskAttemptcounterGroup | array of task attempt counterGroup objects(JSON)/zero or more task attempt counterGroup objects(XML) | A collection of task attempt counter group objects |

#### Elements of the *taskAttemptCounterGroup* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| counterGroupName | string | The name of the counter group |
| counter | array of counter objects(JSON)/zero or more counter objects(XML) | A collection of counter objects |

#### Elements of the *counter* object

| Item | Data Type | Description |
|:---- |:---- |:---- |
| name | string | The name of the counter |
| value | long | The value of the counter |

#### Response Examples

**JSON response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0/attempts/attempt_1326381300833_2_2_m_0_0/counters

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/json
      Transfer-Encoding: chunked
      Server: Jetty(6.1.26)

Response Body:

    {
       "jobTaskAttemptCounters" : {
          "taskAttemptCounterGroup" : [
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.FileSystemCounter",
                "counter" : [
                   {
                      "value" : 2363,
                      "name" : "FILE_BYTES_READ"
                   },
                   {
                      "value" : 54372,
                      "name" : "FILE_BYTES_WRITTEN"
                   },
                   {
                      "value" : 0,
                      "name" : "FILE_READ_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "FILE_LARGE_READ_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "FILE_WRITE_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "HDFS_BYTES_READ"
                   },
                   {
                      "value" : 0,
                      "name" : "HDFS_BYTES_WRITTEN"
                   },
                  {
                      "value" : 0,
                      "name" : "HDFS_READ_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "HDFS_LARGE_READ_OPS"
                   },
                   {
                      "value" : 0,
                      "name" : "HDFS_WRITE_OPS"
                   }
                ]
             },
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.TaskCounter",
                "counter" : [
                   {
                      "value" : 0,
                      "name" : "COMBINE_INPUT_RECORDS"
                   },
                   {
                      "value" : 0,
                      "name" : "COMBINE_OUTPUT_RECORDS"
                   },
                   {
                      "value" : 460,
                      "name" : "REDUCE_INPUT_GROUPS"
                   },
                   {
                      "value" : 2235,
                      "name" : "REDUCE_SHUFFLE_BYTES"
                   },
                   {
                      "value" : 460,
                      "name" : "REDUCE_INPUT_RECORDS"
                   },
                   {
                      "value" : 0,
                      "name" : "REDUCE_OUTPUT_RECORDS"
                   },
                   {
                      "value" : 0,
                      "name" : "SPILLED_RECORDS"
                   },
                   {
                      "value" : 1,
                      "name" : "SHUFFLED_MAPS"
                   },
                   {
                      "value" : 0,
                      "name" : "FAILED_SHUFFLE"
                   },
                   {
                      "value" : 1,
                      "name" : "MERGED_MAP_OUTPUTS"
                   },
                   {
                      "value" : 26,
                      "name" : "GC_TIME_MILLIS"
                   },
                   {
                      "value" : 860,
                      "name" : "CPU_MILLISECONDS"
                   },
                   {
                      "value" : 107839488,
                      "name" : "PHYSICAL_MEMORY_BYTES"
                   },
                   {
                      "value" : 1123147776,
                      "name" : "VIRTUAL_MEMORY_BYTES"
                   },
                   {
                      "value" : 57475072,
                      "name" : "COMMITTED_HEAP_BYTES"
                   }
                ]
             },
             {
                "counterGroupName" : "Shuffle Errors",
                "counter" : [
                   {
                      "value" : 0,
                      "name" : "BAD_ID"
                   },
                   {
                      "value" : 0,
                      "name" : "CONNECTION"
                   },
                   {
                      "value" : 0,
                      "name" : "IO_ERROR"
                   },
                   {
                      "value" : 0,
                      "name" : "WRONG_LENGTH"
                   },
                   {
                      "value" : 0,
                      "name" : "WRONG_MAP"
                   },
                   {
                      "value" : 0,
                      "name" : "WRONG_REDUCE"
                   }
                ]
             },
             {
                "counterGroupName" : "org.apache.hadoop.mapreduce.lib.output.FileOutputFormatCounter",
                "counter" : [
                   {
                      "value" : 0,
                      "name" : "BYTES_WRITTEN"
                   }
                ]
             }
          ],
          "id" : "attempt_1326381300833_2_2_m_0_0"
       }
    }

**XML response**

HTTP Request:

      GET http://<history server http address:port>/ws/v1/history/mapreduce/jobs/job_1326381300833_2_2/tasks/task_1326381300833_2_2_m_0/attempts/attempt_1326381300833_2_2_m_0_0/counters
      Accept: application/xml

Response Header:

      HTTP/1.1 200 OK
      Content-Type: application/xml
      Content-Length: 2735
      Server: Jetty(6.1.26)

Response Body:

    <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
    <jobTaskAttemptCounters>
      <id>attempt_1326381300833_2_2_m_0_0</id>
      <taskAttemptCounterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.FileSystemCounter</counterGroupName>
        <counter>
          <name>FILE_BYTES_READ</name>
          <value>2363</value>
        </counter>
        <counter>
          <name>FILE_BYTES_WRITTEN</name>
          <value>54372</value>
        </counter>
        <counter>
          <name>FILE_READ_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>FILE_LARGE_READ_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>FILE_WRITE_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_BYTES_READ</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_BYTES_WRITTEN</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_READ_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_LARGE_READ_OPS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>HDFS_WRITE_OPS</name>
          <value>0</value>
        </counter>
      </taskAttemptCounterGroup>
      <taskAttemptCounterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.TaskCounter</counterGroupName>
        <counter>
          <name>COMBINE_INPUT_RECORDS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>COMBINE_OUTPUT_RECORDS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>REDUCE_INPUT_GROUPS</name>
          <value>460</value>
        </counter>
        <counter>
          <name>REDUCE_SHUFFLE_BYTES</name>
          <value>2235</value>
        </counter>
        <counter>
          <name>REDUCE_INPUT_RECORDS</name>
          <value>460</value>
        </counter>
        <counter>
          <name>REDUCE_OUTPUT_RECORDS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>SPILLED_RECORDS</name>
          <value>0</value>
        </counter>
        <counter>
          <name>SHUFFLED_MAPS</name>
          <value>1</value>
        </counter>
        <counter>
          <name>FAILED_SHUFFLE</name>
          <value>0</value>
        </counter>
        <counter>
          <name>MERGED_MAP_OUTPUTS</name>
          <value>1</value>
        </counter>
        <counter>
          <name>GC_TIME_MILLIS</name>
          <value>26</value>
        </counter>
        <counter>
          <name>CPU_MILLISECONDS</name>
          <value>860</value>
        </counter>
        <counter>
          <name>PHYSICAL_MEMORY_BYTES</name>
          <value>107839488</value>
        </counter>
        <counter>
          <name>VIRTUAL_MEMORY_BYTES</name>
          <value>1123147776</value>
        </counter>
        <counter>
          <name>COMMITTED_HEAP_BYTES</name>
          <value>57475072</value>
        </counter>
      </taskAttemptCounterGroup>
      <taskAttemptCounterGroup>
        <counterGroupName>Shuffle Errors</counterGroupName>
        <counter>
          <name>BAD_ID</name>
          <value>0</value>
        </counter>
        <counter>
          <name>CONNECTION</name>
          <value>0</value>
        </counter>
        <counter>
          <name>IO_ERROR</name>
          <value>0</value>
        </counter>
        <counter>
          <name>WRONG_LENGTH</name>
          <value>0</value>
        </counter>
        <counter>
          <name>WRONG_MAP</name>
          <value>0</value>
        </counter>
        <counter>
          <name>WRONG_REDUCE</name>
          <value>0</value>
        </counter>
      </taskAttemptCounterGroup>
      <taskAttemptCounterGroup>
        <counterGroupName>org.apache.hadoop.mapreduce.lib.output.FileOutputFormatCounter</counterGroupName>
        <counter>
          <name>BYTES_WRITTEN</name>
          <value>0</value>
        </counter>
      </taskAttemptCounterGroup>
    </jobTaskAttemptCounters>
