I didn't have concerns about Spark, rather I already felt comfortable with Hadoop.
Another issue is that I am sort of retired now. I still accept small consulting jobs and do a lot of writing but my technology choices have shifted to fun things like Pharo Smalltalk, Haskell, etc.
Another issue is that I am sort of retired now. I still accept small consulting jobs and do a lot of writing but my technology choices have shifted to fun things like Pharo Smalltalk, Haskell, etc.