MapReduce Programming Series Seven MapReduce program log view

First of all, if you need to print the log, do not need to use log4j these things, directly with the SYSTEM.OUT.PRINTLN can, these output to stdout log information can be found at the Jobtracker site finally.

Second, assume that when the main function is started, the log printed with SYSTEM.OUT.PRINTLN can be seen directly on the console.

Second, Jobtracker website is very important.

http://your_name_node:50030/jobtracker.jsp

Note that it is not necessarily correct to see map 100% here, and sometimes it is stuck in the map stage and not finished, and at this point the map 100% is displayed, so a layer of points to go in, until you see the log.

In addition, Map/reduce slots can be seen in the cluster summary table to facilitate understanding of cluster computing resources. Can write a script to collect slots information, convenient to analyze the cluster peak and spare time period.

MapReduce Programming Series Seven MapReduce program log view