In order to efficiently use ElasticSearch, it is very important to understand how it works. The goal of this chapter is to give the reader an overview of the basic concepts of ElasticSearch such as node, index, shard, type, records, and fields.
ElasticSearch can be used both as a search engine and as a data store. A brief description of the ElasticSearch logic helps the user to improve the performance and quality, and decide when and how to invest in infrastructure to improve scalability and availability. Some details about data replications and base node communication processes are also explained. At the end of this chapter the protocols used to manage ElasticSearch are also discussed.
