1. Basic concepts
ElasticSearch is a distributed, free and open search and analysis engine for all types of data, including textual, numerical, geospatial, structured and unstructured data. Elasticsearch is built on Apache Lucene and was first released in 2010 by Elasticsearch NV (now known as Elastic). Known for its simple REST API, distributed nature, speed, and scalability, Elasticsearch is a core component of the Elastic Stack, a set of free and open tools for data ingestion, enrichment, storage, analysis, and visualization.