Documentation Grafana Cloud Instrument and send data Grafana Alloy Reference Components otelcol otelcol.exporter.prometheus

otelcol.exporter.prometheus

otelcol.exporter.prometheus accepts OTLP-formatted metrics from other otelcol components, converts metrics to Prometheus-formatted metrics, and forwards the resulting metrics to prometheus components.

You can specify multiple otelcol.exporter.prometheus components by giving them different labels.

Usage

alloy Copy

otelcol.exporter.prometheus "<LABEL>" {
  forward_to = [...]
}

Arguments

You can use the following arguments with otelcol.exporter.prometheus:

By default, OpenTelemetry resources are converted into target_info metrics. OpenTelemetry instrumentation scopes are converted into otel_scope_info metrics. Set the include_scope_info and include_target_info arguments to false, respectively, to disable the custom metrics.

When include_scope_labels is true the otel_scope_name and otel_scope_version labels are added to every converted metric sample.

When include_target_info is true, OpenTelemetry Collector resources are converted into target_info metrics.

Blocks

You can use the following blocks with otelcol.exporter.prometheus:

debug_metrics

The debug_metrics block configures the metrics that this component generates to monitor its state.

The following arguments are supported:

disable_high_cardinality_metrics is the Alloy equivalent to the telemetry.disableHighCardinalityMetrics feature gate in the OpenTelemetry Collector. It removes attributes that could cause high cardinality metrics. For example, attributes with IP addresses and port numbers in metrics about HTTP and gRPC connections are removed.

Exported fields

The following fields are exported and can be referenced by other components:

input accepts otelcol.Consumer data for metrics. Other telemetry signals are ignored.

Metrics sent to the input are converted to Prometheus-compatible metrics and are forwarded to the forward_to argument.

The following are dropped during the conversion process:

• Metrics that use the delta aggregation temporality.

  Note

  Prometheus doesn’t natively support delta metrics. If your Alloy instance ingests delta OTLP metrics, you can convert them to cumulative OTLP metrics with otelcol.processor.deltatocumulative before you use otelcol.exporter.prometheus.

Component health

otelcol.exporter.prometheus is only reported as unhealthy if given an invalid configuration.

Debug information

otelcol.exporter.prometheus doesn’t expose any component-specific debug information.

Example

Basic usage

This example accepts metrics over OTLP and forwards it using prometheus.remote_write:

alloy Copy

otelcol.receiver.otlp "default" {
  grpc {}

  output {
    metrics = [otelcol.exporter.prometheus.default.input]
  }
}

otelcol.exporter.prometheus "default" {
  forward_to = [prometheus.remote_write.mimir.receiver]
}

prometheus.remote_write "mimir" {
  endpoint {
    url = "http://mimir:9009/api/v1/push"
  }
}

Create Prometheus labels from OTLP resource attributes

This example uses otelcol.processor.transform to add extra key1 and key2 OTLP metric datapoint attributes from the key1 and key2 OTLP resource attributes.

otelcol.exporter.prometheus then converts key1 and key2 to Prometheus labels along with any other OTLP metric datapoint attributes.

This avoids the need to set resource_to_telemetry_conversion to true, which could have created too many unnecessary metric labels.

alloy Copy

otelcol.receiver.otlp "default" {
  grpc {}

  output {
    metrics = [otelcol.processor.transform.default.input]
  }
}

otelcol.processor.transform "default" {
  error_mode = "ignore"

  metric_statements {
    context = "datapoint"

    statements = [
      `set(attributes["key1"], resource.attributes["key1"])`,
      `set(attributes["key2"], resource.attributes["key2"])`,
    ]
  }

  output {
    metrics = [otelcol.exporter.prometheus.default.input]
  }
}

otelcol.exporter.prometheus "default" {
  forward_to = [prometheus.remote_write.mimir.receiver]
}

prometheus.remote_write "mimir" {
  endpoint {
    url = "http://mimir:9009/api/v1/push"
  }
}

Compatible components

otelcol.exporter.prometheus can accept arguments from the following components:

• Components that export Prometheus MetricsReceiver

otelcol.exporter.prometheus has exports that can be consumed by the following components:

• Components that consume OpenTelemetry otelcol.Consumer