Diagnosing the Hadoop cluster

As you get into deeper configuration and analysis, you will start facing new issues as you progress. This might include exceptions coming from programs, failing nodes, or even random errors. In this section, we will try to cover how they can be identified and addressed. Note that we will look at debugging MapReduce programs in Chapter 4, Developing MapReduce Applications; this section is more focused on debugging issues pertaining to the Hadoop cluster.

Working with log files

Logging into Hadoop uses the rolling file mechanism based on First In, First Out. There are different types of log files intended for developers, administrators, and other users. You can find out the location of these log...