Elasticsearch is a complex software incomparable to other mainstream database software, whether it’s RDBMS or NoSQL. It functions primarily as your search engine and works as your document database to store valuable data for analytics.
Elasticsearch works as part of the ELK stack (Elastic, Logstash, Beats, and Kibana). It can also be used with other external visualization tools such as Grafana or Knowi, for example. However, we’ll not cover these tools in this blog.
Instead, we will focus on setting up a single node and then transitioning to a 3-node cluster, with default security using SSL/TLS socket for communication.
Elasticsearch has various ways to achieve this installation and setup. But it can be tedious and difficult to install if you stumble into problems. Especially with the recent version releases, as there have been several vital changes and some settings may not work in your current configuration setup.
Here, we will guide you to install Elasticsearch version 8.2.0 on an Ubuntu 20.04.3 LTS (Focal Fossa) environment.
Thanks Paul Namuag
https://severalnines.com/blog/how-to-setup-and-install-elasticsearch-cluster/
More
https://www.elastic.co/guide/en/elasticsearch/reference/8.15/deb.html#deb-repo
Logstash & Grok & Elasticsearch
https://coralogix.com/blog/logstash-grok-tutorial-with-examples