.. _kafkarest_monitoring:

Monitoring
----------

The REST proxy reports a variety of metrics through JMX. It can also be configured to report
stats using additional pluggable stats reporters using the ``metrics.reporters`` configuration
option.

The easiest way to view the available metrics is to use jconsole to browse JMX MBeans. In
addition to the metrics specific to the REST proxy listed below, you can also view and monitor
the metrics for the underlying producers and consumers.

The REST proxy has two types of metrics. Global metrics help you monitor the overall health of
the service. Per-endpoint metrics monitor each API endpoint request method and are
prefixed by a name of the endpoint (e.g. ``brokers.list``). These help you
understand how the proxy is being used and track down specific performance problems.

In addition to the metrics defined below, the REST proxy also exposes the
wealth of metrics that are provided by the underlying Jetty server.

Global Metrics
~~~~~~~~~~~~~~

**MBean: kafka.rest:type=jetty-metrics**

  ``connections-active``
    Total number of active TCP connections.

  ``connections-accepted-rate`` (deprecated since 2.0)
    * In 1.x: The average rate per second of accepted TCP connections.
    * In 2.x: Same as ``connections-opened-rate``.

  ``connections-opened-rate``
    The average rate per second of opened TCP connections.

  ``connections-closed-rate``
    The average rate per second of closed TCP connections.


Per-Endpoint Metrics
~~~~~~~~~~~~~~~~~~~~

The following are the metrics available for each endpoint request method. Metrics for all
requests are also aggregated into a global instance for each one. These aggregate instances have
no prefix in their name.

**MBean: kafka.rest:type=jersey-metrics**

  ``<endpoint>.request-byte-rate``
    Bytes/second of incoming requests

  ``<endpoint>.request-error-rate``
    The average number of requests per second that resulted in HTTP error responses

  ``<endpoint>.request-latency-avg``
    The average request latency in ms

  ``<endpoint>.request-latency-max``
    The maximum request latency in ms

  ``<endpoint>.request-rate``
    The average number of HTTP requests per second.

  ``<endpoint>.request-size-avg``
    The average request size in bytes

  ``<endpoint>.request-size-max``
    The maximum request size in bytes

  ``<endpoint>.response-byte-rate``
    Bytes/second of outgoing responses

  ``<endpoint>.response-rate``
    The average number of HTTP responses per second.

  ``<endpoint>.response-size-avg``
    The average response size in bytes

  ``<endpoint>.response-size-max``
    The maximum response size in bytes


Endpoints
~~~~~~~~~

The following is a list of all the API endpoint methods. The naming should map intuitively to
each of the API operations. To create a full metric name, prefix a per-endpoint metric name with
one of these values. For example, to find the rate of ``GET /brokers`` API calls, combine the
endpoint name ``brokers.list`` with the metric name ``request-rate`` to get
``brokers.list.request-rate``.

  ============================== ===================================================================
  ``brokers.list``               ``GET /brokers``
  ``consumer.commit``            ``POST /consumers/{group}/instances/{instance}/offsets``
  ``consumer.create``            ``POST /consumers/{group}``
  ``consumer.delete``            ``DELETE /consumers/{group}/instances/{instance}``
  ``consumer.topic.read-avro``   ``GET /consumers/{group}/instances/{instance}/topics/{topic}``
                                 with ``Accept: application/vnd.kafka.avro.v1+json`` header
  ``consumer.topic.read-binary`` ``GET /consumers/{group}/instances/{instance}/topics/{topic}``
                                 with ``Accept: application/vnd.kafka.binary.v1+json`` header
  ``partition.get``              ``GET /topics/{topic}/partitions/{partition}``
  ``partition.produce-avro``     ``POST /topics/{topic}/partitions/{partition}`` with
                                 ``Content-Type: application/vnd.kafka.avro.v1+json`` header
  ``partition.produce-binary``   ``POST /topics/{topic}/partitions/{partition}`` with
                                 ``Content-Type: application/vnd.kafka.binary.v1+json`` header
  ``partitions.list``            ``GET /topics/{topic}/partitions``
  ``topic.get``                  ``GET /topics/{topic}``
  ``topic.produce-avro``         ``POST /topics/{topic}`` with
                                 ``Content-Type: application/vnd.kafka.avro.v1+json`` header
  ``topic.produce-binary``       ``POST /topics/{topic}`` with
                                 ``Content-Type: application/vnd.kafka.binary.v1+json`` header
  ``topics.list``                ``GET /topics``
  ============================== ===================================================================