我看到的是Hadoop,但是当我试图提交一个mapreduce作业时,Hadoop似乎启动了,但却挂起了,没有进度或其他活动的指示。应用程序状态页上说它已经提交并显示了作业,但是什么都没有发生,我很好奇在哪里可以解决这个问题。在
我使用的是Hadoop 2.7.1版,安装在OS X 10.10.4中,使用的是Homebrew和Java1.8.0_45。我按照以下说明配置了它:https://datarecipe.wordpress.com/2015/06/05/setup-hadoop-2-6-on-mac-osx-10-9/
数据是一个简单的文本文件,名为“采购.txt“包含此内容(制表符分隔):
2013-03-29 2:30 miami cup 2.43 visa
2013-04-23 1:34 miami cup 2.43 visa
2013-04-23 10:15 LA spoon 1.32 visa
2013-04-28 6:34 LA bottle 3.56 cash
2013-05-23 1:43 miami glass 3.21 visa
我已经用(已创建的数据文件夹)将此上载到hadoop:
^{pr2}$然后,我在python中设置了以下映射器(根据在线教程),并将其命名为“映射器.py“:
import sys
def mapper():
for line in sys.stdin:
tempdata = line.strip().split("\n")
for l in tempdata:
if (len(l.split("\t")) == 6):
date, time, store, item, cost, payment = l.split("\t")
print("{0}\t{1}".format(store,cost))
def main():
mapper()
if __name__=="__main__":
main()
我对reducer代码做了同样的处理,并称之为“减速器.py“:
import sys
def reducer():
salesTotal = 0
oldKey = None
for line in sys.stdin:
data = line.strip().split("\t")
if len(data)!=2:
continue
thisKey, thisSale = data
if oldKey and oldKey != thisKey:
print("{0}\t{1}".format(oldKey,salesTotal))
salesTotal=0
oldKey = thisKey
salesTotal+=float(thisSale)
if oldKey != None:
print("{0}\t{1}".format(oldKey,salesTotal))
def main():
reducer()
if __name__=="__main__":
main()
在命令行上测试这些代码:
Tophers-Retina-MBP:Hadoop tkessler$ cat purchases.txt | ./mapper.py | sort | ./reducer.py
LA 4.88
miami 5.640000000000001
但是,当我在Hadoop中运行流进程时,它只是在这里暂停:
Tophers-Retina-MBP:lib tkessler$ hadoop jar ./hadoop-streaming-2.7.1.jar -mapper ~/PycharmProjects/Hadoop/mapper.py -reducer ~/PycharmProjects/Hadoop/reducer.py -file ~/PycharmProjects/Hadoop/mapper.py -input /data -output /project1out
packageJobJar: [/Users/tkessler/PycharmProjects/Hadoop/mapper.py, /var/folders/f_/3zvmc1g95lqgt1cp2dtnrtqw0000gp/T/hadoop-unjar2355518779286421017/] [] /var/folders/f_/3zvmc1g95lqgt1cp2dtnrtqw0000gp/T/streamjob8766144507660069606.jar tmpDir=null
它似乎很好地启动了作业,并接受了映射器和reducer,运行“mapred job-list all”显示作业都在运行,但从未完成,状态只是列为“unknown”。我不确定这是hadoop配置问题,还是其他问题,如果有人有任何见解。在
添加:
当我运行下面的示例命令时,进程似乎只停留在以下行:
Tophers-Retina-MBP:~ tkessler$ hadoop jar /usr/local/Cellar/hadoop/2.7.1/libexec/share/hadoop/mapreduce/hadoop-mapreduce-examples-2.7.1.jar pi 4 1000
Number of Maps = 4
Samples per Map = 1000
Wrote input for Map #0
Wrote input for Map #1
Wrote input for Map #2
Wrote input for Map #3
Starting Job
通过关闭namenode和datanodes清除Hadoop,然后使用
brew uninstall hadoop
卸载它,然后按照本页上的说明进行设置:http://amodernstory.com/2014/09/23/installing-hadoop-on-mac-osx-yosemite/现在似乎工作得很好,所以可能只是对配置做了一点小小的更改(可能是临时文件位置),但它现在处理映射器和reducer非常好。在
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