hadoop搭建集群，运行pi实例，map和reduce0%就失败了，我用的是root用户，hadoop文件夹在桌面，8088页面也是可以看到的，报错如下，请帮忙看看什么问题呀？

Question

执行集群Stack trace: ExitCodeException exitCode=1: /home/hadoop _tmp/nm-local-dir/usercache/root/appcach
cd share/hadoop/mapreduce
hadoop jar hadoop-mapreduce-examples-2.7.1.jar pi 5 5
Exception message: /home/hadoop _tmp/nm-local-dir/usercache/root/appcache/application_1586797329216_0001/container_1586797329216_0001_01_000003/default_container_executor_session.sh: line 3: /home/hadoop: Is a directory
/bin/mv: target _tmp/nm-local-dir/nmPrivate/application_1586797329216_0001/container_1586797329216_0001_01_000003/container_1586797329216_0001_01_000003.pid' is not a directory
Stack trace: ExitCodeException exitCode=1: /home/hadoop _tmp/nm-local-dir/usercache/root/appcache/application_1586797329216_0001/container_1586797329216_0001_01_000003/default_container_executor_session.sh: line 3: /home/hadoop: Is a directory
/bin/mv: target_tmp/nm-local-dir/nmPrivate/application_1586797329216_0001/container_1586797329216_0001_01_000003/container_1586797329216_0001_01_000003.pid' is not a directory
Exception from container-launch.
Container id: container_1586797329216_0001_01_000003
Exit code: 1
Exception message: /home/hadoop _tmp/nm-local-dir/usercache/root/appcache/application_1586797329216_0001/container_1586797329216_0001_01_000003/default_container_executor_session.sh: line 3: /home/hadoop: Is a directory
/bin/mv: target `_tmp/nm-local-dir/nmPrivate/application_1586797329216_0001/container_1586797329216_0001_01_000003/container_1586797329216_0001_01_000003.pid' is not a directory

Stack trace: ExitCodeException exitCode=1: /home/hadoop _tmp/nm-local-dir/usercache/root/appcache/application_1586797329216_0001/container_1586797329216_0001_01_000003/default_container_executor_session.sh: line 3: /home/hadoop: Is a directory
/bin/mv: target `_tmp/nm-local-dir/nmPrivate/application_1586797329216_0001/container_1586797329216_0001_01_000003/container_1586797329216_0001_01_000003.pid' is not a directory

at org.apache.hadoop.util.Shell.runCommand(Shell.java:545)
at org.apache.hadoop.util.Shell.run(Shell.java:456)
at org.apache.hadoop.util.Shell$ShellCommandExecutor.execute(Shell.java:722)
at org.apache.hadoop.yarn.server.nodemanager.DefaultContainerExecutor.launchContainer(DefaultContainerExecutor.java:211)
at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:302)
at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:82)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

Container exited with a non-zero exit code 1

Answer 1

让阿豪来帮你解答，本回答参考chatgpt3.5编写提供，如果还有疑问可以评论或留言

根据提供的执行集群Stack trace信息，可以看出是在执行Hadoop MapReduce的`pi`作业时出现了异常，具体问题在于`/home/hadoop`被当做一个目录处理，而不是一个可执行文件。 解决方法如下：检查`hadoop-mapreduce-examples-2.7.1.jar`包是否正确配置，确保`pi`作业可以正确访问`/home/hadoop`。另外，检查文件夹结构和权限，确保所需的文件和目录可被程序正常访问。 案例代码如下：

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.util.ToolRunner;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.examples.*;
public class CalculatePi implements Tool {
    private Configuration conf;
    public static void main(String[] args) {
        Configuration conf = new Configuration();
        CalculatePi calculatePi = new CalculatePi();
        calculatePi.setConf(conf);
        int res = ToolRunner.run(calculatePi, args);
        System.exit(res);
    }
    @Override
    public int run(String[] args) throws Exception {
        if (args.length != 2) {
            System.err.println("Usage: CalculatePi <numMaps> <numSamples>");
            return 1;
        }
        int numMaps = Integer.parseInt(args[0]);
        int numSamples = Integer.parseInt(args[1]);
        Job piJob = PiEstimator.createJob(numMaps, numSamples);
        if (piJob.waitForCompletion(true)) {
            return 0;
        } else {
            return 1;
        }
    }
    @Override
    public void setConf(Configuration conf) {
        this.conf = conf;
    }
    @Override
    public Configuration getConf() {
        return conf;
    }
}

以上是一个简单的示例代码，演示了如何使用Hadoop MapReduce计算Pi的近似值。对于pi作业中涉及的/home/hadoop目录，需要确保文件和目录的权限设置正确，且程序能够正确访问。