报错：HDFS IO error org.apache.hadoop.security.AccessControlException: Permission denied: user=root, access=WRITE, inode="/yk/dl/alarm_his":hdfs:supergroup:drwxr-xr-x

报错背景：

CDH集成了Flume服务，准备通过Flume将kafka中的数据放到HDFS中，

启动Flume的时候报错。

报错现象：

19/05/08 10:15:24 INFO hdfs.HDFSDataStream: Serializer = TEXT, UseRawLocalFileSystem = false
19/05/08 10:15:24 INFO hdfs.BucketWriter: Creating hdfs://master:8020/yk/dl/alarm_his/AlarmHis.1557281724769.txt.tmp
19/05/08 10:15:26 WARN hdfs.HDFSEventSink: HDFS IO error
org.apache.hadoop.security.AccessControlException: Permission denied: user=root, access=WRITE, inode="/yk/dl/alarm_his":hdfs:supergroup:drwxr-xr-x
    at org.apache.hadoop.hdfs.server.namenode.DefaultAuthorizationProvider.checkFsPermission(DefaultAuthorizationProvider.java:279)
    at org.apache.hadoop.hdfs.server.namenode.DefaultAuthorizationProvider.check(DefaultAuthorizationProvider.java:260)
    at org.apache.hadoop.hdfs.server.namenode.DefaultAuthorizationProvider.check(DefaultAuthorizationProvider.java:240)
    at org.apache.hadoop.hdfs.server.namenode.DefaultAuthorizationProvider.checkPermission(DefaultAuthorizationProvider.java:162)
    at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:152)
    at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:3885)
    at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:3868)
    at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkAncestorAccess(FSDirectory.java:3850)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.checkAncestorAccess(FSNamesystem.java:6820)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInternal(FSNamesystem.java:2974)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFileInt(FSNamesystem.java:2890)
    at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.startFile(FSNamesystem.java:2774)
    at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.create(NameNodeRpcServer.java:610)
    at org.apache.hadoop.hdfs.server.namenode.AuthorizationProviderProxyClientProtocol.create(AuthorizationProviderProxyClientProtocol.java:117)
    at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.create(ClientNamenodeProtocolServerSideTranslatorPB.java:413)
    at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
    at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:617)
    at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:1073)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2281)
    at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2277)
    at java.security.AccessController.doPrivileged(Native Method)
    at javax.security.auth.Subject.doAs(Subject.java:422)
    at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1924)
    at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2275)

    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:423)
    at org.apache.hadoop.ipc.RemoteException.instantiateException(RemoteException.java:106)
    at org.apache.hadoop.ipc.RemoteException.unwrapRemoteException(RemoteException.java:73)
    at org.apache.hadoop.hdfs.DFSOutputStream.newStreamForCreate(DFSOutputStream.java:2136)
    at org.apache.hadoop.hdfs.DFSClient.create(DFSClient.java:1804)
    at org.apache.hadoop.hdfs.DFSClient.create(DFSClient.java:1728)
    at org.apache.hadoop.hdfs.DistributedFileSystem$7.doCall(DistributedFileSystem.java:438)
    at org.apache.hadoop.hdfs.DistributedFileSystem$7.doCall(DistributedFileSystem.java:434)
    at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)
    at org.apache.hadoop.hdfs.DistributedFileSystem.create(DistributedFileSystem.java:434)
    at org.apache.hadoop.hdfs.DistributedFileSystem.create(DistributedFileSystem.java:375)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:926)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:907)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:804)
    at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:793)
    at org.apache.flume.sink.hdfs.HDFSDataStream.doOpen(HDFSDataStream.java:81)
    at org.apache.flume.sink.hdfs.HDFSDataStream.open(HDFSDataStream.java:108)
    at org.apache.flume.sink.hdfs.BucketWriter$1.call(BucketWriter.java:262)
    at org.apache.flume.sink.hdfs.BucketWriter$1.call(BucketWriter.java:252)
    at org.apache.flume.sink.hdfs.BucketWriter$9$1.run(BucketWriter.java:701)
    at org.apache.flume.auth.SimpleAuthenticator.execute(SimpleAuthenticator.java:50)
    at org.apache.flume.sink.hdfs.BucketWriter$9.call(BucketWriter.java:698)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

报错原因：

根据日志信息可以解读出，root用户想要在文件系统里面创建一个目录，失败。

 原因是，root用户无法操作hdfs

报错解决：

重启HDFS即可