This is a common misconception. Spark Master and Spark driver are two independent and isolated JVM's running on the same instance. Spark Master's responsibilities are to ensure the Spark worker's daemons are up and running and monitor the health. Also, manage the resource on the Spark cluster. Spark Master acts as the cluster manager in the Spark Standalone architecture. The Spark driver is the brain of the Spark engine. 

https://spark.apache.org/docs/latest/cluster-overview.html

https://spark.apache.org/docs/latest/spark-standalone.html