hadoop 配置：无法加载或找到主类 org.apache.hadoop

Question

我正在尝试学习 hadoop，我正在学习来自复数视觉的“hadoop 的构建块”课程，当我运行以下命令时，我正在尝试通过伪分布式模式运行 hadoop：

bin/hadoop jar share/hadoop/mapreduce/hadoop-mapreduce-examples-3.0.3.jar grep input output 'dfs[a-z.]+'

我得到以下输出：

Application application_1530031734419_0001 failed 2 times due to AM Container for appattempt_1530031734419_0001_000002 exited with exitCode: 1
Failing this attempt.Diagnostics: [2018-06-26 16:50:21.067]Exception from container-launch.
Container id: container_1530031734419_0001_02_000001
Exit code: 1
[2018-06-26 16:50:21.076]Container exited with a non-zero exit code 1. Error file: prelaunch.err.
Last 4096 bytes of prelaunch.err :
Last 4096 bytes of stderr :
Error: Could not find or load main class org.apache.hadoop.mapreduce.v2.app.MRAppMaster
Please check whether your etc/hadoop/mapred-site.xml contains the below configuration:
<property>
<name>yarn.app.mapreduce.am.env</name>
<value>HADOOP_MAPRED_HOME=${full path of your hadoop distribution directory}</value>
</property>
<property>
<name>mapreduce.map.env</name>
<value>HADOOP_MAPRED_HOME=${full path of your hadoop distribution directory}</value>
</property>
<property>
<name>mapreduce.reduce.env</name>
<value>HADOOP_MAPRED_HOME=${full path of your hadoop distribution directory}</value>
</property>
[2018-06-26 16:50:21.077]Container exited with a non-zero exit code 1. Error file: prelaunch.err.
Last 4096 bytes of prelaunch.err :
Last 4096 bytes of stderr :
Error: Could not find or load main class org.apache.hadoop.mapreduce.v2.app.MRAppMaster
Please check whether your etc/hadoop/mapred-site.xml contains the below configuration:
<property>
<name>yarn.app.mapreduce.am.env</name>
<value>HADOOP_MAPRED_HOME=${full path of your hadoop distribution directory}</value>
</property>
<property>
<name>mapreduce.map.env</name>
<value>HADOOP_MAPRED_HOME=${full path of your hadoop distribution directory}</value>
</property>
<property>
<name>mapreduce.reduce.env</name>
<value>HADOOP_MAPRED_HOME=${full path of your hadoop distribution directory}</value>
</property>
For more detailed output, check the application tracking page: http://homestead:8088/cluster/app/application_1530031734419_0001 Then click on links to logs of each attempt.
. Failing the application.

我已经尝试关注这个日志，也搜索过类似的问题，基本上看起来错误是在一些配置文件中，所以他们在这里：

mapred-site.xml

<configuration>
        <property>
                <name>mapreduce.framework.name</name>
                <value>yarn</value>
        </property>
        <property>
                <name>yarn.app.mapreduce.am.env</name>
                <value>HADOOP_MAPRED_HOME=~/hadoop-install/hadoop-3.0.3</value>
        </property>
        <property>
                <name>mapreduce.map.env</name>
                <value>HADOOP_MAPRED_HOME=~/hadoop-install/hadoop-3.0.3</value>
        </property>
        <property>
                <name>mapreduce.reduce.env</name>
                <value>HADOOP_MAPRED_HOME=~/hadoop-install/hadoop-3.0.3</value>
        </property>
        <property>
                <name>mapreduce.application.classpath</name>
                <value>$HADOOP_MAPRED_HOME/,$HADOOP_MAPRED_HOME/lib/,$MR2_CLASS</value>
</property>
</configuration>

hadoop-env.sh //因为这个文件很大，我只带了我从默认文件中改变的东西

export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64
export HADOOP_HOME=~/hadoop-install/hadoop-3.0.3
export YARN_HOME=$HADOOP_HOME

plus：来自 sbin/start-all.sh 的所有进程都在运行。操作系统是 ubuntu，但通过 Windows 10 计算机上的虚拟机运行。 hadoop 版本是 3.0.3

Answer 1

当它说

${full path of your hadoop distribution directory}

1) 您需要保证 Hadoop 集群中每台机器上的路径都相同

2) 完整路径意味着路径中没有~/