如何在hadoop中执行MapReduce作业期间在控制台上进行打印 [英] How to print on console during MapReduce job execution in hadoop

问题描述

类似于

System.out.println（完成第一步）;
System.out.println（Completed Step two）;

等等

是否有一个特殊的命令来做到这一点，或者根本不可能呢，因为System.out.println似乎根本不起作用？

您可以使用 System.out.println（.. 。要查看打印什么，打开JobTracker Web控制台，然后导航到你提交的作业链接，在Job页面上，你会看到指向你所有个人Map / Reduce任务的链接，点击链接..你会发现一个显示转储的链接标准输出以及标准错误。

I want to print each step of my "map" after its execution on the console.

Something like

System.out.println("Completed Step one"); System.out.println("Completed Step two");

and so on

Is there a special command to do that or is it not possible at all, as System.out.println doesn't seem to work at all ?

Please guide

解决方案

You can use System.out.println(... To see whats been printed, open the jobtracker web console. Then navigate to your submitted job's link. On the Job page, you will see links to all your individual Map/Reduce tasks. Follow the links.. you will find a link that displays the dump of both the Standard output as well as the Standard error.

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