groups = rbinom(32,n=50,prob=0.4)
groupsdfs =to.dfs(groups)
mapreduceResult<- mapreduce(
     input =groupsdfs,
     map =function(.,v) keyval(v,1),
     reduce = function(k,vv) keyval(k,sum(vv)))
from.dfs(mapreduceResult)

14/07/24 11:22:59 INFO mapreduce.Job:  map 100% reduce 58%
14/07/24 11:23:01 INFO mapreduce.Job: Task Id :  attempt_1406189659246_0001_r_000016_1,      Status : FAILED
Error: java.lang.RuntimeException: Error in configuring object
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:109)
at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:75)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:133)
at org.apache.hadoop.mapred.ReduceTask.runOldReducer(ReduceTask.java:409)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:392)
at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:168)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1548)
at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:163)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:106)
 ... 9 more
 Caused by: java.lang.RuntimeException: configuration exception
 at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:222)
at org.apache.hadoop.streaming.PipeReducer.configure(PipeReducer.java:67)
... 14 more
Caused by: java.io.IOException: Cannot run program "Rscript": error=2, No such file or directory
 at java.lang.ProcessBuilder.start(ProcessBuilder.java:1041)
 at org.apache.hadoop.streaming.PipeMapRed.configure(PipeMapRed.java:209)
... 15 more
Caused by: java.io.IOException: error=2, No such file or directory
at java.lang.UNIXProcess.forkAndExec(Native Method)
at java.lang.UNIXProcess.<init>(UNIXProcess.java:135)
at java.lang.ProcessImpl.start(ProcessImpl.java:130)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1022)
... 16 more

14/07/24 11:23:42 INFO mapreduce.Job: Job job_1406189659246_0001 failed with state FAILED due to: Task failed task_1406189659246_0001_r_000007

14/07/24 11:23:42 INFO mapreduce.Job: Counters: 54
    File System Counters
    FILE: Number of bytes read=1631
    FILE: Number of bytes written=2036200
    FILE: Number of read operations=0
    FILE: Number of large read operations=0
    FILE: Number of write operations=0
    HDFS: Number of bytes read=1073
    HDFS: Number of bytes written=5198
    HDFS: Number of read operations=67
    HDFS: Number of large read operations=0
    HDFS: Number of write operations=38
Job Counters
    Failed map tasks=2
    Failed reduce tasks=28
    Killed reduce tasks=1
    Launched map tasks=4
    Launched reduce tasks=48
    Other local map tasks=2
    Data-local map tasks=2
     Total time spent by all maps in occupied slots (ms)=18216
     Total time spent by all reduces in occupied slots (ms)=194311
     Total time spent by all map tasks (ms)=18216
     Total time spent by all reduce tasks (ms)=194311
     Total vcore-seconds taken by all map tasks=18216
     Total vcore-seconds taken by all reduce tasks=194311
     Total megabyte-seconds taken by all map tasks=18653184
     Total megabyte-seconds taken by all reduce tasks=198974464
 Map-Reduce Framework
     Map input records=3
     Map output records=25
     Map output bytes=2196
     Map output materialized bytes=2266
     Input split bytes=214
    Combine input records=0
     Combine output records=0
    Reduce input groups=10
     Reduce shuffle bytes=1859
    Reduce input records=21
     Reduce output records=30
    Spilled Records=46
     Shuffled Maps =38
    Failed Shuffles=0
    Merged Map outputs=38
    GC time elapsed (ms)=1339
     CPU time spent (ms)=40060
     Physical memory (bytes) snapshot=5958418432
     Virtual memory (bytes) snapshot=33795457024
     Total committed heap usage (bytes)=7176978432
 Shuffle Errors
    BAD_ID=0
    CONNECTION=0
    IO_ERROR=0
    WRONG_LENGTH=0
    WRONG_MAP=0
    WRONG_REDUCE=0
File Input Format Counters
    Bytes Read=859
File Output Format Counters
    Bytes Written=5198
rmr
    reduce calls=10
14/07/24 11:23:42 ERROR streaming.StreamJob: Job not Successful!
Streaming Command Failed!
Error in mr(map = map, reduce = reduce, combine = combine, vectorized.reduce,  :
  hadoop streaming failed with error code 1

Sys.setenv(HADOOP_CMD="/usr/bin/hadoop")
        Sys.setenv(HADOOP_STREAMING="/opt/cloudera/parcels/CDH-5.1.0-1.cdh5.1.0.p0.53/lib/hadoop-0.20-mapreduce/contrib/streaming/hadoop-streaming.jar")
        Sys.setenv(JAVA_HOME="/usr/java/jdk1.7.0_55-cloudera")
        Sys.setenv(HADOOP_COMMON_LIB_NATIVE_DIR="/opt/cloudera/parcels/CDH-5.1.0-1.cdh5.1.0.p0.53/lib/hadoop/lib/native")
        Sys.setenv(HADOOP_OPTS="-Djava.library.path=HADOOP_HOME/lib")
        library(rhdfs)
        hdfs.init()
        library(rmr2)

        ## space and word delimiter
        map <- function(k,lines) {
          words.list <- strsplit(lines, '\s')
          words <- unlist(words.list)
          return( keyval(words, 1) )
        }
        reduce <- function(word, counts) {
          keyval(word, sum(counts))
        }
        wordcount <- function (input, output=NULL) {
          mapreduce(input=input, output=output, input.format="text", map=map, reduce=reduce)
        }

        ## variables
        hdfs.root <- '/user/node'
        hdfs.data <- file.path(hdfs.root, 'data')
        hdfs.out <- file.path(hdfs.root, 'out')

        ## run mapreduce job
        ##out <- wordcount(hdfs.data, hdfs.out)
        system.time(out <- wordcount(hdfs.data, hdfs.out))

        ## fetch results from HDFS
        results <- from.dfs(out)
        results.df <- as.data.frame(results, stringsAsFactors=F)
        colnames(results.df) <- c('word', 'count')

        ##head(results.df)
        ## sorted output TOP10
        head(results.df[order(-results.df$count),],10)