Beats are the lightweight data shippers from Elastic.co (the company behind Elasticsearch). Beats are designed to be easy to configure and run.
Beats are the client part of the equation, living on the systems that are to be monitored. Beats capture metrics, logs, and more from servers across the environment and ship them to either Logstash for further processing or Elasticsearch for indexing and analysis.
There are multiple official Beats (which are developed and maintained by Elastic), and a multitude of open source Beats have been developed by the community.
The main Beats that we'll be using for this setup are Filebeat and Metricbeat.