# OTLP metrics export to Prometheus

LLMS index: [llms.txt](/llms.txt)

---

## Introduction

Prometheus was designed and optimized for pull-based monitoring, where it
discovers targets and scrapes metrics endpoints at regular intervals. This model
is central to its architecture, supporting features like service discovery and
consistent target-based collection.

With the growing adoption of OpenTelemetry, newer versions of Prometheus have
introduced support for receiving push-based metrics via OTLP. In this setup,
OpenTelemetry SDKs export metrics using OTLP over HTTP, and Prometheus acts as
an OTLP receiver instead of scraping metrics. This approach can be used in
simpler setups, experiments, or local development environments. However, for
production deployments using OpenTelemetry, it is strongly recommended to use an
[OpenTelemetry Collector](/docs/collector/#when-to-use-a-collector) as an
intermediary.

This guide explains how to configure direct OTLP metric export from
OpenTelemetry SDKs to a Prometheus OTLP endpoint. It covers required environment
variables, exporter configuration, and key considerations such as service
identification, export intervals, and operational trade-offs.

## Prerequisite

Before you begin, make sure the following requirements are met:

- Set up Prometheus. Follow the
  [example prometheus.yml configuration in this Prometheus guide](https://prometheus.io/docs/guides/opentelemetry/#configuring-prometheus).
- [Enable the OTLP receiver](https://prometheus.io/docs/guides/opentelemetry/#enable-the-otlp-receiver)

Once you have Prometheus set up, you can move on to configure your application
to send metrics directly to an OTLP ingestion endpoint.

### Use environment variables

You can configure OpenTelemetry SDKs and instrumentation libraries with
[standard environment variables](/docs/languages/sdk-configuration/). Set the
environment variables before starting your application. The following
OpenTelemetry variables are needed to send OpenTelemetry metrics to a Prometheus
server on localhost:

```bash
export OTEL_EXPORTER_OTLP_PROTOCOL=http/protobuf
export OTEL_EXPORTER_OTLP_METRICS_ENDPOINT=http://localhost:9090/api/v1/otlp
```

Turn off traces and logs when using Prometheus if you only need metrics:

```bash
export OTEL_TRACES_EXPORTER=none
export OTEL_LOGS_EXPORTER=none
```

The default push interval for OpenTelemetry metrics is 60 seconds. This can be
adjusted depending on monitoring requirements. For example, a 15-second interval
provides more responsive metrics and faster alerting at the cost of higher
network and processing overhead.

```bash
export OTEL_METRIC_EXPORT_INTERVAL=15000
```

If your instrumentation library does not provide `service.name` and
`service.instance.id` out-of-the-box, it is highly recommended to set them.
Without these attributes, it becomes difficult to reliably identify services or
distinguish between instances, making debugging and aggregation significantly
harder. The example below assumes that the `uuidgen` command is available on
your system.

```bash
export OTEL_SERVICE_NAME="my-example-service"
export OTEL_RESOURCE_ATTRIBUTES="service.instance.id=$(uuidgen)"
```

> [!NOTE]
>
> Make sure that `service.instance.id` is unique for each instance, and that a
> new `service.instance.id` is generated whenever a resource attribute changes.
> The [recommended way](/docs/specs/semconv/resource/service/#service-instance)
> is to generate a new UUID on each startup of an instance.

### Configure telemetry

Update your OpenTelemetry configuration to use the same `exporter` and `reader`
from the OTLP setup in your
[language SDK documentation](/docs/languages/_index.md). If the environment
variables are set up and loaded correctly, the OpenTelemetry SDK reads them
automatically.