我对在Hadoop中建立和执行我的第一份工作感到非常困惑，并希望能够澄清我所看到的错误并提供指导的任何人提供帮助：）
我有一个我编译过的JAR文件。当我尝试在OSX中使用它执行M / R作业时，我得到SCDynamicStore错误，该错误通常与HADOOP_OPTS环境变量相关联。但是，当我从示例JAR文件运行示例时，这不会发生。我在hadoop-env.sh中设置了变量，它似乎在群集中被识别。
从hadoop-examples.jar运行测试：
$ hadoop jar /usr/local/Cellar/hadoop/1.1.2/libexec/hadoop-examples-1.1.2.jar wordcount /stock/data /stock/count.out
13/06/22 13:21:51 INFO input.FileInputFormat: Total input paths to process : 3
13/06/22 13:21:51 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
13/06/22 13:21:51 WARN snappy.LoadSnappy: Snappy native library not loaded
13/06/22 13:21:51 INFO mapred.JobClient: Running job: job_201306221315_0003
13/06/22 13:21:52 INFO mapred.JobClient: map 0% reduce 0%
13/06/22 13:21:56 INFO mapred.JobClient: map 66% reduce 0%
13/06/22 13:21:58 INFO mapred.JobClient: map 100% reduce 0%
13/06/22 13:22:04 INFO mapred.JobClient: map 100% reduce 33%
13/06/22 13:22:05 INFO mapred.JobClient: map 100% reduce 100%
13/06/22 13:22:05 INFO mapred.JobClient: Job complete: job_201306221315_0003
...
使用我自己的类运行作业不起作用：
$ hadoop jar test.jar mapreduce.X /data /output
13/06/22 13:38:36 WARN mapred.JobClient: Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same.
13/06/22 13:38:36 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
13/06/22 13:38:36 WARN snappy.LoadSnappy: Snappy native library not loaded
13/06/22 13:38:36 INFO mapred.FileInputFormat: Total input paths to process : 3
13/06/22 13:38:36 INFO mapred.JobClient: Running job: job_201306221328_0002
13/06/22 13:38:37 INFO mapred.JobClient: map 0% reduce 0%
13/06/22 13:38:44 INFO mapred.JobClient: Task Id : attempt_201306221328_0002_m_000000_0, Status : FAILED
java.lang.RuntimeException: Error in configuring object
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:93)
at org.apache.hadoop.util.ReflectionUtils.setConf(ReflectionUtils.java:64)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:117)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:432)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:372)
at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1149)
at org.apache.hadoop.mapred.Child.main(Child.java:249)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.hadoop.util.ReflectionUtils.setJobConf(ReflectionUtils.java:88)
... 9 more
Caused by: java.lang.NoClassDefFoundError: com/google/gson/TypeAdapterFactory
at mapreduce.VerifyMarket$Map.<clinit>(VerifyMarket.java:26)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:249)
at org.apache.hadoop.conf.Configuration.getClassByName(Configuration.java:802)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:847)
at org.apache.hadoop.conf.Configuration.getClass(Configuration.java:873)
at org.apache.hadoop.mapred.JobConf.getMapperClass(JobConf.java:947)
at org.apache.hadoop.mapred.MapRunner.configure(MapRunner.java:34)
... 14 more
Caused by: java.lang.ClassNotFoundException: com.google.gson.TypeAdapterFactory
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 22 more
attempt_201306221328_0002_m_000000_0: 2013-06-22 13:38:39.314 java[60367:1203] Unable to load realm info from SCDynamicStore
13/06/22 13:38:44 INFO mapred.JobClient: Task Id : attempt_201306221328_0002_m_000001_0, Status : FAILED
... (This repeats a few times, but hopefully this is enough to see what I mean.)
最初，我认为这与前面提到的环境变量有关，但现在我不太确定。也许我的JAR打包不正确？
答案 0 :(得分：0)
最简单的答案是将项目转换为Maven并在POM中包含gson依赖项。现在mvn package获取所有必需的依赖项并创建一个JAR文件，其中包含完成集群中作业所需的所有内容。