Apache Spark在Hadoop纱线上工作的问题

Question

我对大数据非常陌生，尤其是Apache Spark/Hadoop YARN。

为了进行一些尝试，我在虚拟机中安装了Hadoop单个节点，我还添加了Spark。

我认为环境安装得很好，因为我可以访问：

• http://172.30.10.64:50070 -> Hadoop概述
• http://172.30.10.64:8080 ->火花概述

然后，我创建了一个pythonic文件，它允许计数单词：

from pyspark import SparkConf, SparkContext

from operator import add
import sys
## Constants
APP_NAME = " HelloWorld of Big Data"
##OTHER FUNCTIONS/CLASSES

def main(sc,filename):
   textRDD = sc.textFile(filename)
   words = textRDD.flatMap(lambda x: x.split(' ')).map(lambda x: (x, 1))
   wordcount = words.reduceByKey(add).collect()
   for wc in wordcount:
      print wc[0],wc[1]

if __name__ == "__main__":

   # Configure Spark
   conf = SparkConf().setAppName(APP_NAME)
   conf = conf.setMaster("local[*]")
   sc   = SparkContext(conf=conf)
   filename = sys.argv[1]
   # Execute Main functionality
   main(sc, filename)

我也有一个名为data.txt的文本文件。我将此文件上传到HDFS中：

hadoop fs -put data.txt hdfs://localhost:9000

我的文件位于：hdfs://localhost:9000/user/hduser上

因此，我想要执行我的pythonic脚本感谢火花/Hadoop。

我做了：./bin/spark-submit /home/hduser/count.py /home/hduser/data.txt

但我明白：

Traceback (most recent call last):
  File "/home/hduser/count.py", line 25, in <module>
    main(sc, filename)
  File "/home/hduser/count.py", line 13, in main
    wordcount = words.reduceByKey(add).collect()
  File "/usr/local/spark/python/lib/pyspark.zip/pyspark/rdd.py", line 1623, in reduceByKey
  File "/usr/local/spark/python/lib/pyspark.zip/pyspark/rdd.py", line 1849, in combineByKey
  File "/usr/local/spark/python/lib/pyspark.zip/pyspark/rdd.py", line 2259, in _defaultReducePartitions
  File "/usr/local/spark/python/lib/pyspark.zip/pyspark/rdd.py", line 2455, in getNumPartitions
  File "/usr/local/spark/python/lib/py4j-0.10.6-src.zip/py4j/java_gateway.py", line 1160, in __call__
  File "/usr/local/spark/python/lib/py4j-0.10.6-src.zip/py4j/protocol.py", line 320, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o21.partitions.
: org.apache.hadoop.mapred.InvalidInputException: Input path does not exist: hdfs://localhost:9000/home/hduser/data.txt
    at org.apache.hadoop.mapred.FileInputFormat.singleThreadedListStatus(FileInputFormat.java:285)
    at org.apache.hadoop.mapred.FileInputFormat.listStatus(FileInputFormat.java:228)
    at org.apache.hadoop.mapred.FileInputFormat.getSplits(FileInputFormat.java:313)
    at org.apache.spark.rdd.HadoopRDD.getPartitions(HadoopRDD.scala:200)
    at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:253)
    at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:251)
    at scala.Option.getOrElse(Option.scala:121)
    at org.apache.spark.rdd.RDD.partitions(RDD.scala:251)
    at org.apache.spark.rdd.MapPartitionsRDD.getPartitions(MapPartitionsRDD.scala:35)
    at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:253)
    at org.apache.spark.rdd.RDD$$anonfun$partitions$2.apply(RDD.scala:251)
    at scala.Option.getOrElse(Option.scala:121)
    at org.apache.spark.rdd.RDD.partitions(RDD.scala:251)
    at org.apache.spark.api.java.JavaRDDLike$class.partitions(JavaRDDLike.scala:61)
    at org.apache.spark.api.java.AbstractJavaRDDLike.partitions(JavaRDDLike.scala:45)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:244)
    at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:357)
    at py4j.Gateway.invoke(Gateway.java:282)
    at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:132)
    at py4j.commands.CallCommand.execute(CallCommand.java:79)
    at py4j.GatewayConnection.run(GatewayConnection.java:214)
    at java.lang.Thread.run(Thread.java:748)

这很奇怪，因为我的data.txt文件已进入HDFS，但我有以下问题：Input path does not exist: hdfs://localhost:9000/home/hduser/data.txt

知道吗？

Answer 1

您的URL无效。HDFS中没有home文件夹。试一试：

./bin/spark-submit /home/hduser/count.py /user/hduser/data.txt

Answer 2

确保在星星之火-env.sh中设置了HADOOP_HOME和SPARK_HOME路径变量。这样，您就可以使用HDFS执行I/O操作，并将作业提交到纱线集群。