我在Ubuntu上将Hadoop 3.1.2作为单节点安装。我正在尝试运行Hadoop随附的wordcount示例。我正在使用的命令如下：
hadoop jar $HADOOP_HOME/share/hadoop/mapreduce/hadoop-mapreduce-examples-3.1.2.jar wordcount /usr/hduser/wordcount/input /usr/hduser/wordcount/output
我在HDFS的/ usr / hduser / input中有两个文件。当我运行代码时，出现此错误：
ENOENT: No such file or directory
at org.apache.hadoop.io.nativeio.NativeIO$POSIX.chmodImpl(Native Method)
at org.apache.hadoop.io.nativeio.NativeIO$POSIX.chmod(NativeIO.java:233)
at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:836)
at org.apache.hadoop.fs.ChecksumFileSystem$1.apply(ChecksumFileSystem.java:508)
at org.apache.hadoop.fs.ChecksumFileSystem$FsOperation.run(ChecksumFileSystem.java:489)
at org.apache.hadoop.fs.ChecksumFileSystem.setPermission(ChecksumFileSystem.java:511)
at org.apache.hadoop.fs.FileSystem.mkdirs(FileSystem.java:676)
at org.apache.hadoop.mapreduce.JobResourceUploader.mkdirs(JobResourceUploader.java:658)
at org.apache.hadoop.mapreduce.JobResourceUploader.uploadResourcesInternal(JobResourceUploader.java:172)
at org.apache.hadoop.mapreduce.JobResourceUploader.uploadResources(JobResourceUploader.java:133)
at org.apache.hadoop.mapreduce.JobSubmitter.copyAndConfigureFiles(JobSubmitter.java:99)
at org.apache.hadoop.mapreduce.JobSubmitter.submitJobInternal(JobSubmitter.java:194)
at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1570)
at org.apache.hadoop.mapreduce.Job$11.run(Job.java:1567)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/javax.security.auth.Subject.doAs(Subject.java:423)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1729)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:1567)
at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:1588)
at org.apache.hadoop.examples.WordCount.main(WordCount.java:87)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.apache.hadoop.util.ProgramDriver$ProgramDescription.invoke(ProgramDriver.java:71)
at org.apache.hadoop.util.ProgramDriver.run(ProgramDriver.java:144)
at org.apache.hadoop.examples.ExampleDriver.main(ExampleDriver.java:74)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:564)
at org.apache.hadoop.util.RunJar.run(RunJar.java:318)
at org.apache.hadoop.util.RunJar.main(RunJar.java:232)
如果创建目录/ usr / hduser / wordcount / output，则会出现错误，指出FileAlreadyExists，但是我很确定Hadoop希望在运行mapreduce作业之前不存在输出目录，所以我不应该这样做。创建它。
我不知道其中一个配置文件中是否缺少某些内容或什么内容。