I need to read more about these 5. Apache Flink, Apache Samza, Ibis, Apache Twill and Apache Mahout-samsara. Mahout is the one I have read a bit about but others were not on my radar yet.
There are a lot of open source projects out there, and keeping track of them all is next to impossible. Here are five important ones in the Big Data space that you may not know about.