How could I configure from Java (or Scala) code amount of executors having `SparkConfig` and `SparkContext`? I see constantly 2 executors. Looks like `spark.default.parallelism` does not work and is about something different.

I just need to set amount of executors to be equal to cluster size but there are always only 2 of them. I know my cluster size. I run on YARN if this matters.