SparkR was merged. So let's have this umbrella JIRA for the ML pipeline API in SparkR. The implementation should be similar to the pipeline API implementation in Python.-
We limited the scope of this JIRA to MLlib + SparkR integration for 1.5.
For Spark 1.5, we want to support linear/logistic regression in SparkR, with basic support for R formula and elastic-net regularization. The design doc can be viewed at https://docs.google.com/document/d/10NZNSEurN2EdWM31uFYsgayIPfCFHiuIu3pCWrUmP_c/edit?usp=sharing