Installing Elasticsearch

At the time of writing this book, Elasticsearch 2.3.2 is the current stable release and Elasticsearch 5 is in alpha testing. For production clusters, we recommend using the 2.3.2 release and quickly updating to the 5 general availability (GA) release once it is available. Note that while Elasticsearch 5 is compatible with indices created in Elasticsearch 2.x, there have also been some API changes and feature deprecations after the 1.x release. Readers should account for these important changes before upgrading. More details on upgrading from 2.x to 5 can be found on the Elastic website at the following URLS:

• https://www.elastic.co/blog/elasticsearch-5-0-0-alpha1-released
• https://www.elastic.co/blog/elasticsearch-5-0-0-alpha2-released

Notable API changes include the following:

• Indices from Elasticsearch 1.x must first be upgraded to 2.x before finally moving to version 5
• The deprecated filtered, or, and and queries were removed in favor of the bool, must, and should...