In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "It is important to note that the fsimage file is not updated for every write operation."

A block of code is set as follows:

<property>
  <name>dfs.namenode.servicerpc-address</name>
  <value>node1.hcluster:8022</value>
</property>

Any command-line input or output is written as follows:

$ sudo yum install flume-ng
$ sudo yum install flume-ng-agent

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "The Coordinators tab lists all the coordinator applications that have been configured in Oozie."