java - 将外部 jar 设置为 hadoop 类路径

Question

我正在尝试将外部 jar 设置为 hadoop 类路径，但到目前为止还没有成功。

我有以下设置

$ hadoop version
Hadoop 2.0.6-alpha Subversion https://git-wip-us.apache.org/repos/asf/bigtop.git -r ca4c88898f95aaab3fd85b5e9c194ffd647c2109 Compiled by jenkins on 2013-10-31T07:55Z From source with checksum 95e88b2a9589fa69d6d5c1dbd48d4e This command was run using /usr/lib/hadoop/hadoop-common-2.0.6-alpha.jar

类路径

$ echo $HADOOP_CLASSPATH
/home/tom/workspace/libs/opencsv-2.3.jar

我可以看到上面的 HADOOP_CLASSPATH 已经被 hadoop 获取

$ hadoop classpath
/etc/hadoop/conf:/usr/lib/hadoop/lib/:/usr/lib/hadoop/.//:/home/tom/workspace/libs/opencsv-2.3.jar:/usr/lib/hadoop-hdfs/./:/usr/lib/hadoop-hdfs/lib/:/usr/lib/hadoop-hdfs/.//:/usr/lib/hadoop-yarn/lib/:/usr/lib/hadoop-yarn/.//:/usr/lib/hadoop-mapreduce/lib/:/usr/lib/hadoop-mapreduce/.//

命令

$ sudo hadoop jar FlightsByCarrier.jar FlightsByCarrier /user/root/1987.csv /user/root/result

我也尝试了 -libjars 选项

$ sudo hadoop jar FlightsByCarrier.jar FlightsByCarrier /user/root/1987.csv /user/root/result -libjars /home/tom/workspace/libs/opencsv-2.3.jar

堆栈跟踪

14/11/04 16:43:23 INFO mapreduce.Job: Running job: job_1415115532989_0001 14/11/04 16:43:55 INFO mapreduce.Job: Job job_1415115532989_0001 running in uber mode : false 14/11/04 16:43:56 INFO mapreduce.Job: map 0% reduce 0% 14/11/04 16:45:27 INFO mapreduce.Job: map 50% reduce 0% 14/11/04 16:45:27 INFO mapreduce.Job: Task Id : attempt_1415115532989_0001_m_000001_0, Status : FAILED Error: java.lang.ClassNotFoundException: au.com.bytecode.opencsv.CSVParser at java.net.URLClassLoader$1.run(URLClassLoader.java:366) at java.net.URLClassLoader$1.run(URLClassLoader.java:355) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:354) at java.lang.ClassLoader.loadClass(ClassLoader.java:425) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308) at java.lang.ClassLoader.loadClass(ClassLoader.java:358) at FlightsByCarrierMapper.map(FlightsByCarrierMapper.java:19) at FlightsByCarrierMapper.map(FlightsByCarrierMapper.java:10) at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144) at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:757) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:339) at org.apache.hadoop.mapred.YarnChild$2.run(YarnChild.java:158) 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:1478) at org.apache.hadoop.mapred.YarnChild.main(YarnChild.java:153)

非常感谢任何帮助。

Answer 1

运行 map 的节点上缺少您的外部 jar。您必须将其添加到缓存中才能使其可用。尝试:

DistributedCache.addFileToClassPath(new Path("pathToJar"), conf);

不确定 DistributedCache 在哪个版本中被弃用，但从 Hadoop 2.2.0 开始您可以使用:

job.addFileToClassPath(new Path("pathToJar"));