我刚刚开始使用Hadoop 2。
使用基本配置安装后，我总是无法运行任何示例。有没有人看到这个问题，请帮助我？
错误是这样的
Error starting MRAppMaster
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
这是日志
20152015-01-06 11:56:23,194 INFO [main] org.apache.hadoop.mapreduce.v2.app.MRAppMaster: Created MRAppMaster for application appattempt_1420510526926_0002_000001
2015-01-06 11:56:23,362 FATAL [main] org.apache.hadoop.mapreduce.v2.app.MRAppMaster: Error starting MRAppMaster
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:131)
at org.apache.hadoop.security.Groups.<init>(Groups.java:70)
at org.apache.hadoop.security.Groups.<init>(Groups.java:66)
at org.apache.hadoop.security.Groups.getUserToGroupsMappingService(Groups.java:280)
at org.apache.hadoop.security.UserGroupInformation.initialize(UserGroupInformation.java:271)
at org.apache.hadoop.security.UserGroupInformation.setConfiguration(UserGroupInformation.java:299)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.initAndStartAppMaster(MRAppMaster.java:1473)
at org.apache.hadoop.mapreduce.v2.app.MRAppMaster.main(MRAppMaster.java:1429)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:129)
... 7 more
Caused by: java.lang.UnsatisfiedLinkError: org.apache.hadoop.security.JniBasedUnixGroupsMapping.anchorNative()V
at org.apache.hadoop.security.JniBasedUnixGroupsMapping.anchorNative(Native Method)
at org.apache.hadoop.security.JniBasedUnixGroupsMapping.<clinit>(JniBasedUnixGroupsMapping.java:49)
at org.apache.hadoop.security.JniBasedUnixGroupsMappingWithFallback.<init>(JniBasedUnixGroupsMappingWithFallback.java:39)
... 12 more
2015-01-06 11:56:23,366 INFO [main] org.apache.hadoop.util.ExitUtil: Exiting with status 1
错误消息："启动 MRAppMaster 时出错"、"InvocationTargetException"、"UnsatisfiedLinkError"
根本原因：无法执行类"org.apache.hadoop.security.JniBasedUnixGroupsMapping"中的本机函数"anchorNative"
描述：函数"anchorNative"将调用库"libhadoop.so"中的函数。此库的路径由以下环境变量指定：
export JAVA_LIBRARY_PATH
export HADOOP_COMMON_LIB_NATIVE_DIR
在 Hadoop 源代码中，打印 java 库类路径
System.err.println( (System.getProperty("java.library.path") );
# result
/home/maidinh/hadoop2/build/hadoop-2.6.0-src/hadoop-dist/target/hadoop-2.6.0/lib/native:
/usr/java/packages/lib/amd64:
/usr/lib64:
/lib64:
/lib:
/usr/lib
可以在这些发生冲突的位置找到不同版本的库"libhadoop.so"。
解决方案：除了原生库的正确路径（在 hadoop-2.6.0/lib/native 中），删除其他目录中的所有"libhadoop.so"。
注意：删除所有相关的Hadoop库
rm -r libhadoop*
rm -r libhdfs*