16

我是 Hadoop 新手。我使用此链接在我的 MAC 上安装了 Hadoop

一开始它对我来说就像一个魅力，但现在当我从 Eclipse 运行相同的 WordCount 问题时，我遇到了这个问题：

ERROR security.UserGroupInformation: PriviledgedActionException as:<username> cause:java.net.UnknownHostException: <hostname>: <hostname>: hostname nor servname provided, or not known
Exception in thread "main" java.net.UnknownHostException: <hostname>: <hostname>: nodename nor servname provided, or not known
    at java.net.InetAddress.getLocalHost(InetAddress.java:1466)
    at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:960)
    at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:936)
    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.mapred.JobClient.submitJobInternal(JobClient.java:936)
    at org.apache.hadoop.mapreduce.Job.submit(Job.java:550)
    at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:580)
    at WordCount.main(WordCount.java:57)
Caused by: java.net.UnknownHostException: <hostname>: nodename nor servname provided, or not known
    at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)

这就是我的 conf 文件的外观：

核心站点.xml：

<configuration>

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

</configuration>

hadoop-env.sh

除了默认值外，还有以下条目：

export HADOOP_OPTS="-Djava.security.krb5.realm=OX.AC.UK -Djava.security.krb5.kdc=kdc0.ox.ac.uk:kdc1.ox.ac.uk"

hdfs-site.xml

<configuration>

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

</configuration>

mapred-site.xml

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

我在错误的开头也看到了这一点：

2013-10-11 21:03:08.795 java[7484:1903] Unable to load realm mapping info from SCDynamicStore
13/10/11 21:03:08 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
13/10/11 21:03:08 WARN mapred.JobClient: Use GenericOptionsParser for parsing the arguments. Applications should implement Tool for the same.
13/10/11 21:03:08 WARN mapred.JobClient: No job jar file set.  User classes may not be found. See JobConf(Class) or JobConf#setJar(String).
13/10/11 21:03:08 INFO mapred.JobClient: Cleaning up the staging area file:/tmp/hadoop-<uname>/mapred/staging/<uname>386844365/.staging/job_local386844365_0001

如果我做错了什么，有人可以告诉我吗？我的程序是相同的并且没有更改默认值（以前可以工作）

谢谢

4

3 回答 3

36

问题出在主机文件上。通过将其添加到 /etc/hosts 文件来修复它：

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
127.0.1.1   <hostname>
于 2013-10-12T07:14:27.077 回答
25

你可以用一个简单的命令来解决这个问题：

echo "127.0.0.1 $HOSTNAME" | sudo tee -a /etc/hosts

（来源）

于 2014-12-11T12:15:32.690 回答
0

在我的MAC上，原来是ISP提供的DNS当时被污染或错误。将系统 DNS 设置为 8.8.8.8（Google DNS 的主 DNS 服务器）或其他公共 DNS 解决了我的问题。

于 2020-03-19T02:26:38.557 回答