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Metrics Exporters

Metrics exporters are responsible for passing the recorded metrics to a metric storage. They can implement a push approach where metrics are sent to a collector or a pull approach where metrics are scraped by an external system.

If an exporter supports run-time updates it means that it can be enabled/disabled during the run-time or that any property related to the exporter can be changed. This way you can, for example, change the endpoint where exporter pushes the metrics without a need to restart the application. In order to use run-time updates, you must enable one of the externalized configuration methods that support dynamic updates.

inspectIT Ocelot currently supports the following metrics exporters:

Exporter	Supports run-time updates	Push / Pull	Enabled by default
Logging Exporter (Metrics) [Homepage]	Yes	Push	No
Prometheus Exporter	Yes	Pull	No
InfluxDB Exporter	Yes	Push	No
OTLP Exporter (Metrics) [Homepage]	Yes	Push	No

Important note: Starting with version 2.0.0, inspectIT Ocelot moved from OpenCensus to OpenTelemetry. As a result, the OpenCensus Agent Exporter is no longer supported.

Logging Exporter (Metrics)

The Logging exporter exports the metrics to the system log. By default, the exporter is disabled. The following properties are nested properties below the inspectit.exporters.metrics.logging:

Property	Default	Description
.enabled	DISABLED	If ENABLED or IF_CONFIGURED, the inspectIT Ocelot agent will try to start the Logging metrics exporter.
.export-interval	refers to inspectit.metrics.frequency	The export interval of the metrics.

Prometheus Exporter

Prometheus exporter exposes the metrics in Prometheus format and is the default metrics exporter set up by inspectIT Ocelot. When enabled, inspectIT starts a Prometheus HTTP server in parallel with your application. The server is by default started on the port 8888 and metrics can then be accessed by visiting http://localhost:8888/metrics.

The following properties are nested properties below the inspectit.exporters.metrics.prometheus property:

Property	Default	Description
.enabled	DISABLED	If ENABLED or IF_CONFIGURED, the inspectIT Ocelot agent will try to start the Prometheus metrics exporter and Prometheus HTTP server.
.host	0.0.0.0	The hostname or network address to which the Prometheus HTTP server should bind.
.port	8888	The port the Prometheus HTTP server should use.

Don't forget to check the official OpenTelemetry Prometheus exporter documentation.

InfluxDB Exporter

If enabled, metrics are pushed at a specified interval directly to a given InfluxDB v1.x instance. To enable the InfluxDB Exporters, it is only required to specify the endpoint.

The InfluxDB exporter provides a special handling for counter and sum metrics which is enabled by default and can be disabled using the counters-as-differences option. Usually, the absolute value of such counters is irrelevant when querying the data, instead you want to have the increase of it over a certain period of time. With the counters-as-differences option enabled, counters are preprocessed before being exported.

Instead of writing the absolute value of each counter into the InfluxDB, only the increase since the last export will be written. In addition, no value will be exported, if the counter has not changed since the last export. This can greatly reduce the amount of data written into the InfluxDB, especially if the metrics are quite constant and won't change much.

The following properties are nested properties below the inspectit.exporters.metrics.influx property:

Property	Default	Description
.enabled	IF_CONFIGURED	If ENABLED or IF_CONFIGURED, the agent will try to start the Influx exporter. If the url is not set, it will log a warning if set to ENABLED but fail silently if set to IF_CONFIGURED.
.endpoint	null	The HTTP endpoint of the InfluxDB, e.g. http://localhost:8086.
.user	null	The user to use for connecting to the InfluxDB, can not be empty.
.password	null	The password to use for connecting to the InfluxDB, can be not be empty.
.database	inspectit	The InfluxDB database to which the metrics are pushed.
.retention-policy	autogen	The retention policy of the database to use for writing metrics.
.create-database	true	If enabled, the database defined by the database property is automatically created on startup with an autogen retention policy if it does not exist yet.
.export-interval	refers to inspectit.metrics.frequency	Defines how often metrics are pushed to the InfluxDB.
.counters-as-differences	true	Defines whether counters are exported using their absolute value or as the increase between exports
buffer-size	40	In case the InfluxDB is not reachable, failed writes will be buffered and written on the next export. This value defines the maximum number of batches to buffer.

OTLP Exporter (Metrics)

The OpenTelemetry Protocol (OTLP) exporters export the metrics to the desired endpoint at a specified interval. To enable the OTLP exporters, it is only required to specify the endpoint.

The following properties are nested properties below the inspectit.exporters.metrics.otlp-grpc property:

Property	Default	Description
.enabled	IF_CONFIGURED	If ENABLED or IF_CONFIGURED, the inspectIT Ocelot agent will try to start the OTLP gRPC metrics exporter.
.endpoint	null	Target to which the exporter is going to send metrics, e.g. http://localhost:4317
.protocol	null	The transport protocol, see OTEL documentation. Supported protocols are grpc and http/protobuf.
.preferredTemporality	CUMULATIVE	The preferred output aggregation temporality, see OTEL documentation. Supported values are CUMULATIVE and DELTA.
.headers	null	Key-value pairs to be used as headers associated with gRPC or HTTP requests, see OTEL documentation.
.compression	NONE	The compression method, see OTEL documentation. Supported compression methods are gzip and none.
.timeout	10s	Maximum time the OTLP exporter will wait for each batch export, see OTEL documentation.

To make inspectIT Ocelot push the metris via OTLP to, e.g. an OpenTelemetry Collector running on the same machine as the agent, the following JVM property can be used:

-Dinspectit.exporters.metrics.otlp.endpoint=http://127.0.0.1:4317
-Dinspectit.exporters.metrics.otlp.protocol=grpc