Let's first start Spark master as follows:
$cd $SPARK_HOME sbin/start-master.sh
Initializing Spark Master
Users can access Spark Master UI on port 8080. After Spark master gets started, the web UI will look as follows:
Spark Master UI
Here, spark-master is the Hostname of the node on which Spark master is running.
The URL shown in the previous screenshot is used while starting slave nodes.
The URL shown in the previous screenshot is used while starting slave nodes.