* [Elasticsearch](https://www.elastic.co/) - A Lucene Based Document store mainly used for log indexing, storage and analysis.
* [Fluentd](http://www.fluentd.org/) - Log Collector and Shipper.
* [Flume](https://flume.apache.org/) - Distributed log collection and aggregation system.
* [GoAccess](http://goaccess.io/) - Real-time web log analyzer and interactive viewer that runs in a terminal or through the browser. ([Source Code](https://github.com/allinurl/goaccess)) `MIT``C`
* [Graylog](https://www.graylog.org/) - Pluggable Log and Event Analysis Server with Alerting options.
* [Heka](http://hekad.readthedocs.org/en/latest/) - Stream processing system which may be used for log aggregation.
* [Kibana](https://www.elastic.co/products/kibana) - Visualize logs and time-stamped data.