This article is based on Recommender System with Mahout and Elasticsearch tutorial created by MapR. It now uses the 20M MovieLens dataset which contains: 20 million ratings and 465 000 tag applications applied to 27 000 movies by 138 000 users and was released in 4/2015. The format with this recent version has changed a bit so I needed to adapt the existing scripts to the new format. Prerequisites Download the 20M MovieLens dataset. Unzip it.