I am performing a distcp between two different clusters. I am doing it selectively, so it goes in a file-per-file basis. The permissions in both clusters are the same. The user executing the distcp is the same (named as xxx in the example). I am encountering an issue when copying, which is asking for execution permissions... for a file!
Caused by: org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.security.AccessControlException): Permission denied: user=xxx, access=EXECUTE, inode="/mypath/myfile":xxx:xxx:-rw-r--r--
at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.check(FSPermissionChecker.java:205)
at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkTraverse(FSPermissionChecker.java:161)
at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:128)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkPermission(FSNamesystem.java:4684)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkTraverse(FSNamesystem.java:4660)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getFileInfo(FSNamesystem.java:2911)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.getFileInfo(NameNodeRpcServer.java:673)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.getFileInfo(ClientNamenodeProtocolServerSideTranslatorPB.java:643)
at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java:44128)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:453)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1002)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1695)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:1691)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:396)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1408)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:1689)
at org.apache.hadoop.ipc.Client.call(Client.java:1225)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Invoker.invoke(ProtobufRpcEngine.java:202)
at $Proxy10.getFileInfo(Unknown Source)
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.io.retry.RetryInvocationHandler.invokeMethod(RetryInvocationHandler.java:164)
at org.apache.hadoop.io.retry.RetryInvocationHandler.invoke(RetryInvocationHandler.java:83)
at $Proxy10.getFileInfo(Unknown Source)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolTranslatorPB.getFileInfo(ClientNamenodeProtocolTranslatorPB.java:628)
at org.apache.hadoop.hdfs.DFSClient.getFileInfo(DFSClient.java:1545)
... 13 more
2015-05-11 10:22:49,005 INFO org.apache.hadoop.mapred.TaskLogsTruncater: Initializing logs' truncater with mapRetainSize=-1 and reduceRetainSize=-1
2015-05-11 10:22:49,008 ERROR org.apache.hadoop.security.UserGroupInformation: PriviledgedActionException as:xxx (auth:SIMPLE) cause:java.io.IOException: Copied: 0 Skipped: 0 Failed: 1
2015-05-11 10:22:49,008 WARN org.apache.hadoop.mapred.Child: Error running child
java.io.IOException: Copied: 0 Skipped: 0 Failed: 1
at org.apache.hadoop.tools.DistCp$CopyFilesMapper.close(DistCp.java:582)
at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:57)
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:418)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:333)
at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
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:1408)
at org.apache.hadoop.mapred.Child.main(Child.java:262)
2015-05-11 10:22:49,013 INFO org.apache.hadoop.mapred.Task: Runnning cleanup for the task
where xxx is my user.
The file in the destination cluster has rw-r--r-- permissions set, and the folder has rwxr-xr-x. The file in the origin cluster has rw-r--r-- permissions set, and the folder has rwxrwxrwx.
So, it's true, the file does not have execute permissions set.
But, why is distcp asking for execution permissions on a file? In HDFS, supposedly, execution permissions for files have no effect. Distcp documentation does not say anything about requiring execute permissions.
Note: I am using -overwrite option in my distcp - nothing else. Using CDH4.2.1 with distcp version 1.
Apparently this is an undocumented quirk on how distcp handles directories. distcp will not understand the destination file as a file but as a directory. If the file exists it tries to access it as a directory, when it's a file. Hence it fails due to execute permissions.
However, distcp v1 dev and support has been discontinued in favour of distcp v2 (which is a complete rewrite), which replaces distcp on CDH5. This error and others regarding directory handling have changed to a more intuitive, *nix-like schema.