Sure. The story is somewhat different with Hadoop. But it's really quite feasible to adapt your systems incrementally from Hadoop to Spark. One of the details that I elided in the post is that we're just now decommissioning our last Hadoop machine learning job, nearly a year after moving to Spark. These things take time. That's why it's important that new and useful tools like Spark, Impala, etc. work with the existing Hadoop ecosystem.