通过我的 Web 应用程序，我正在尝试运行 mapreduce 作业。当 map reduce 作业运行时，应用程序部署在 tomcat 服务器上 我得到以下异常

15/12/17 23:38:36 ERROR security.UserGroupInformation: PriviledgedActionException as:tomcat7 cause:org.apache.hadoo
p.security.AccessControlException: Permission denied: user=tomcat7, access=WRITE, inode="":hduser:supergroup:rwxr-x
r-x
15/12/17 23:38:36 INFO ipc.Server: IPC Server handler 6 on 54310, call mkdirs(/out/StichedFile/_temporary, rwxr-xr-
x) from 104.154.95.48:41285: error: org.apache.hadoop.security.AccessControlException: Permission denied: user=tomc
at7, access=WRITE, inode="":hduser:supergroup:rwxr-xr-x
org.apache.hadoop.security.AccessControlException: Permission denied: user=tomcat7, access=WRITE, inode="":hduser:s
upergroup:rwxr-xr-x
        at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:217)
        at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:197)
        at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:141)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(FSNamesystem.java:5758)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkAncestorAccess(FSNamesystem.java:5731)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirsInternal(FSNamesystem.java:2502)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.mkdirs(FSNamesystem.java:2469)
        at org.apache.hadoop.hdfs.server.namenode.NameNode.mkdirs(NameNode.java:911)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:587)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1432)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1428)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:415)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1190)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1426)

如何解决这个问题？

最佳答案

这很可能是权限问题。有两种方法可以解决。 您可以在 hdfs-site.xml 中禁用权限

<property> <name>dfs.permissions</name> <value>false</value> </property> 或者您可以在 hadoop 中向用户“tomcat7”授予写入权限。

关于Hadoop PrivilegedActionException，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34364025/