Elasticsearch

This course focuses solely on Elasticsearch, not the total ELK stack (Elastic, Logstash, Kibana).

What is ElasticSearch?

Elasticsearch is an open source analytics and search engine.

Some use cases include:

• Full text search across a product catalogue
• Querying and analysing structures data such as logs or analytics
• Application Performance Management (APM) is a specific use case where you store logs in Elastic and visualise them to monitor application performance (such as a CPU/RAM)
• Send events to ElasticSearch. E.g send sales from physical stores to ElasticSearch

ES is written in Java and is build ontop of Apache Lucene.

How does Elasticsearch work?

Data is stored as documents in ES. A document represents a row in a database and contains fields similar to columns in relational databases.

A document is just a JSON document.

To query these documents we just use a REST API. The query and the document are both JSON objects.