Each instance can report to zero or more sinks. Sinks are contained in the org.apache.spark.metrics.sink package:
ConsoleSink: Logs metrics information to the console. CSVSink: Exports metrics data to CSV files at regular intervals. JmxSink: Registers metrics for viewing in a JMX console. MetricsServlet: Adds a servlet within the existing Spark UI to serve metrics data as JSON data. GraphiteSink: Sends metrics to a Graphite node.