Ever since we open sourced Hadoop in 2006, Yahoo – and now, Oath – has been committed to opening up its big data infrastructure to the larger developer community. Today, we are taking another major step in this direction by making Vespa, Yahoo's big data processing and serving engine, available as open source on GitHub.
source: https://www.oath.com/press/open-sourcing-vespa-yahoo-s-big-data-processing-and-serving-eng/