Increase Spark Executors on Zeppelin
Pietro, you can change that on Zeppelin itself.
On the top right corner, open the menu, and enter the "Interpreter" configuration.
There is a section, called "interpreters". The last subsection is called "spark", and you should find this setting there.
If it is not, just insert it, editing the subsection.
Hope that helps.
From top right corner, click down arrow -> click Interpreter -> find spark2 interpreter -> edit it -> add following two:
- spark.shuffle.service.enabled -> true
- spark.dynamicAllocation.enabled -> true