Metrics

Apache ActiveMQ Artemis can export metrics to a variety of monitoring systems via the Micrometer vendor-neutral application metrics facade.

Important runtime metrics have been instrumented via the Micrometer API, and all a user needs to do is implement org.apache.activemq.artemis.core.server.metrics.ActiveMQMetricsPlugin in order to instantiate and configure a io.micrometer.core.instrument.MeterRegistry implementation. Relevant implementations of MeterRegistry are available from the Micrometer code-base.

This is a simple interface:

public interface ActiveMQMetricsPlugin extends Serializable {

   ActiveMQMetricsPlugin init(Map<String, String> options);

   MeterRegistry getRegistry();
}

When the broker starts it will call init and pass in the options which can be specified in XML as key/value properties. At this point the plugin should instantiate and configure the io.micrometer.core.instrument.MeterRegistry implementation.

Later during the broker startup process it will call getRegistry in order to get the MeterRegistry implementation and use it for registering meters.

The broker ships with two ActiveMQMetricsPlugin implementations:

• org.apache.activemq.artemis.core.server.metrics.plugins.LoggingMetricsPlugin This plugin simply logs metrics. It's not very useful for production, but can serve as a demonstration of the Micrometer integration. It takes no key/value properties for configuration.

• org.apache.activemq.artemis.core.server.metrics.plugins.SimpleMetricsPlugin This plugin is used for testing. It is in-memory only and provides no external output. It takes no key/value properties for configuration.

Metrics

The following metrics are exported, categorized by component. A description for each metric is exported along with the metric itself therefore the description will not be repeated here.

Broker

• connection.count
• total.connection.count
• address.memory.usage

Address

• routed.message.count
• unrouted.message.count

Queue

• message.count
• durable.message.count
• persistent.size
• durable.persistent.size
• delivering.message.count
• delivering.durable.message.count
• delivering.persistent.size
• delivering.durable.persistent.size
• scheduled.message.count
• scheduled.durable.message.count
• scheduled.persistent.size
• scheduled.durable.persistent.size
• messages.acknowledged
• messages.added
• messages.killed
• messages.expired
• consumer.count

It may appear that some higher level broker metrics are missing (e.g. total message count). However, these metrics can be deduced by aggregating the lower level metrics (e.g. aggregate the message.count metrics from all queues to get the total).

JVM memory metrics are exported as well.

Configuration

In broker.xml use the metrics-plugin element and specify the class-name attribute to configure your plugin, e.g.:

<metrics-plugin class-name="org.apache.activemq.artemis.core.server.metrics.plugins.LoggingMetricsPlugin" />

As noted, the plugin can also be configured with key/value properties in order to customize its behavior as necessary, e.g.:

<metrics-plugin class-name="org.example.MyMetricsPlugin">
   <property key="host" value="example.org" />
   <property key="port" value="5162" />
   <property key="foo" value="10" />
</metrics-plugin>