hadoop - 未能检测到有效的 hadoop 主目录

Question

我已经设置了 Hadoop 2.2.0 单节点并启动了它。我可以浏览 FShttp://localhost:50070/ 然后我尝试使用以下代码编写一个虚拟文件。

public class Test {
public void write(File file) throws IOException{
    FileSystem fs = FileSystem.get(new Configuration());
    Path outFile = new Path("test.jpg");       
    FSDataOutputStream out = fs.create(outFile);        

}    

我得到以下异常

INFO:   DEBUG - field org.apache.hadoop.metrics2.lib.MutableRate org.apache.hadoop.security.UserGroupInformation$UgiMetrics.loginSuccess with annotation @org.apache.hadoop.metrics2.annotation.Metric(valueName=Time, value=[Rate of successful kerberos logins and latency (milliseconds)], about=, type=DEFAULT, always=false, sampleName=Ops)
    INFO:   DEBUG - field org.apache.hadoop.metrics2.lib.MutableRate org.apache.hadoop.security.UserGroupInformation$UgiMetrics.loginFailure with annotation @org.apache.hadoop.metrics2.annotation.Metric(valueName=Time, value=[Rate of failed kerberos logins and latency (milliseconds)], about=, type=DEFAULT, always=false, sampleName=Ops)
    INFO:   DEBUG - UgiMetrics, User and group related metrics
    INFO:   DEBUG -  Creating new Groups object
    INFO:   DEBUG - Trying to load the custom-built native-hadoop library...
    INFO:   DEBUG - Failed to load native-hadoop with error: java.lang.UnsatisfiedLinkError: no hadoop in java.library.path
    INFO:   DEBUG - java.library.path=/usr/lib/jvm/jdk1.7.0/jre/lib/amd64:/usr/lib/jvm/jdk1.7.0/jre/lib/i386::/usr/java/packages/lib/i386:/lib:/usr/lib
    INFO:   WARN - Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
    INFO:   DEBUG - Falling back to shell based
    INFO:   DEBUG - Group mapping impl=org.apache.hadoop.security.ShellBasedUnixGroupsMapping
    INFO:   DEBUG - Group mapping impl=org.apache.hadoop.security.JniBasedUnixGroupsMappingWithFallback; cacheTimeout=300000
    INFO:   DEBUG - hadoop login
    INFO:   DEBUG - hadoop login commit
    INFO:   DEBUG - using local user:UnixPrincipal: qualebs
    INFO:   DEBUG - UGI loginUser:qualebs (auth:SIMPLE)
    INFO:   DEBUG - Failed to detect a valid hadoop home directory
    java.io.IOException: HADOOP_HOME or hadoop.home.dir are not set.
        at org.apache.hadoop.util.Shell.checkHadoopHome(Shell.java:225)
        at org.apache.hadoop.util.Shell.<clinit>(Shell.java:250)
        at 
    org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:639)
        at org.apache.hadoop.fs.FilterFileSystem.setPermission(FilterFileSystem.java:468)
        at org.apache.hadoop.fs.ChecksumFileSystem.create(ChecksumFileSystem.java:456)
        at org.apache.hadoop.fs.ChecksumFileSystem.create(ChecksumFileSystem.java:424)
        at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:905)
        at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:886)
        at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:783)
        at org.apache.hadoop.fs.FileSystem.create(FileSystem.java:772)
        at com.qualebs.managers.HadoopDFS.writer(HadoopDFS.java:41)

我在哪里设置 HADOOP_HOME 或 hadoop.home.dir？操作系统是 Ubuntu 11.10

我配置的唯一配置文件如下，添加了属性

1. 核心站点.xml

<configuration>
    <property>
        <name>fs.default.name</name>
        <value>hdfs://localhost:9000</value>
    </property>
</configuration>

2. hdfs-site.xml

<configuration>
    <property>
        <name>dfs.replication</name>
        <value>1</value>
    </property>
</configuration>

3. mapred-site.xml.template

<configuration>
    <property>
        <name>mapred.job.tracker</name>
        <value>localhost:9001</value>
    </property>
</configuration>

热切期待您的回复。

Answer 1

我通过这样做找到了我的解决方案：

System.setProperty("hadoop.home.dir", "/");

此异常由checkHadoopHome()in引发org.apache.hadoop.util.Shell

希望能帮助到你！

Answer 2

此设置不适用于 Windows。一种解决方法是在您的项目上创建一个文件夹（例如 winutils/bin）并将 winutils.exe 放入其中（请参阅https://wiki.apache.org/hadoop/WindowsProblems）。然后在Java代码中添加

static {
    String OS = System.getProperty("os.name").toLowerCase();

    if (OS.contains("win")) {
      System.setProperty("hadoop.home.dir", Paths.get("winutils").toAbsolutePath().toString());
    } else {
      System.setProperty("hadoop.home.dir", "/");
    }
  }

我希望它有所帮助。

Answer 3

如果您没有为 hadoop 使用专用用户，请将其添加到终端 bash 文件中。

1. start terminal
2. sudo vi .bashrc
3. export HADOOP_HOME=YOUR_HADOOP_HOME_DIRECTORY(don't include bin folder)
4. save
5. restart terminal and check it if it's saved by typing : echo $HADOOP_HOME

Answer 4

我从某些东西中得到了同样的错误消息，我不相信它与路径有关。我的记录器设置不正确：

导致错误：

import org.apache.log4j._

trait Logger {
  val logger = LogManager.getRootLogger
}

解决它：

import org.apache.log4j._

trait Logger {
  val logger = LogManager.getRootLogger
  logger.setLevel(Level.INFO)
}

解决方案可能根本不是改变路径。