Monitor Schema Registry in Confluent Platform

Schema Registry reports a variety of metrics through Java Management Extensions (JMX). It can also be configured to report stats using additional pluggable stats reporters using the metric.reporters configuration option. The easiest way to view the available metrics is to use JConsole to browse JMX MBeans.

Schema Registry 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. subjects.get-schema). These help you understand how the proxy is being used and track down specific performance problems.

Tip

Authentication is disabled for JMX by default in Kafka. You must use environment variables to override these defaults. For each platform component, the options to override the JMX defaults take the form <component-name>_JMX_OPTS. Use the following environment variable to override default JMX options for Schema Registry: SCHEMA_REGISTRY_JMX_OPTS.

Global Metrics

MBean: kafka.schema.registry: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.

busy_thread_count

The number of threads currently working on a task (busy threads).

thread_pool_usage

Percentage of total thread pool in use (total/threads in use).

request_queue_size

Number of threads required for requests in the queue.

MBean: kafka.schema.registry:type=master-slave-role

master-slave-role

The current role of this Schema Registry instance. A value of 1 indicates this instance is the primary, 0 indicates it is a secondary.

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.schema.registry: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.

compatibility.subjects.versions.verify	POST /compatibility/subjects/{subject}/versions/{version}
schemas.ids.get-schema	GET /schemas/ids/{id}
subjects.get-schema	POST /subjects/{subject}
subjects.list	GET /subjects
subjects.versions.get-schema	GET /subjects/{subject}/versions/{version}
subjects.versions.get-schema.only	GET /subjects/{subject}/versions/{version}/schema
subjects.versions.list	GET /subjects/{subject}/versions
subjects.versions.register	POST /subjects/{subject}/versions