Metrics APIs

For reporting metrics, we have a package that provides APIs for both Metrics1 and Metrics2. It provides the flexibility to use client libraries and different modules from within an application.

The org.apache.hadoop.metrics package

This package provides sub-packages to do the specified task:

org.apache.hadoop.metrics.spi

The abstract Server Provider Interface package. Those wishing to integrate the metrics API with a particular metrics client library should extend this package:

org.apache.hadoop.metrics.file

An implementation package that writes the metric data to a file or sends it to the standard output stream:

org.apache.hadoop.metrics.ganglia

An implementation package that sends metrics data to Ganglia.

The new Metrics2 provides a lot more packages for the implementation.

The org.apache.hadoop.metrics2 package

• org.apache.hadoop.metrics2.annotation: This is the public annotation that interfaces for simpler metrics instrumentation.

• org.apache.hadoop.metrics2.filter: This is the built...