Storing and Configuring Data with Hadoop, YARN, and ZooKeeper - Big Data Made Easy: A Working Guide to the Complete Hadoop Toolset - page 30

Figure 2-3. The name node user interface
To see the administration information for Map Reduce, go to port 50030 by using the URL http://hc1nn:50030/,
shown in Figure 2-4 . This port number refers to the value of the variable mapred.job.tracker.http.address already
defined in the mapred-site.xml configuration file. Figure 2-4 shows the state of the jobs, as well as the capacity per
node in terms of Map and Reduce. It also shows an example word-count job that's running currently, which that has
completed the Map stage and is 8.33 percent into its Reduce phase.