What you need for this book
This book was written using Elasticsearch 5.0.x, and all the examples and functions should work with it. In addition to that, you'll need a command-line tool that allows you to send HTTP requests such as curl, which are available for most operating systems. Please note that all examples in this book use the mentioned curl tool. If you want to use another tool, please remember to format the request in an appropriate way that is understood by the tool of your choice.
In addition to that, to run examples in Chapter 11, Developing Elasticsearch Plugins, you will need a Java Development Kit (JDK) Version 1.8.0_73 and above installed and an editor that will allow you to develop your code (or a Java IDE such as Eclipse). To build the code and manage dependencies in Chapter 11, Developing Elasticsearch Plugins, we are using Apache Maven.
The last chapter of this book has been written using Elastic Stack 5.0.0, so you will need to have Logstash, Kibana, and Metricbeat, all comprising the same version.
