So I can just logon to the box that is the spark master and run the start master script? Are the slaves already defined or do I need to do that? I'm confused if yarn handles that too or if yarn just starts the master which is already configured out of the box. The problem is you can't connect to yarn from outside the cluster. Or at least not when I tried "yarn-cluster". I'm just looking for a way to easily invoke the spark master from a java service and not have to use spark submit. ... View more