Free and Open Source, Distributed, RESTful Search Engine

Logstash - transport and process your logs, events, or other data

APM, (Application Performance Management) tool for large-scale distributed systems.

Apache Flume is a distributed, reliable, and available service for efficiently collecting, aggregating, and moving large amounts of log-like data

Content Based Image Retrieval Plugin for Elasticsearch. It allows users to index images and search for similar images.