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Promscale natively supports the OpenTelemetry Line Protocol (OTLP) for traces and Prometheus remote write protocol for metrics. You can send traces to Promscale using OTLP with any of the OpenTelemetry client SDKs, instrumentation libraries, or the OpenTelemetry Collector. Currently, Promscale only supports gRPC endpoint for traces. You can send metrics to Promscale HTTP endpoint using Prometheus remote write protocol with the OpenTelemetry Collector. OpenTelemetry Collector converts OTLP metrics to Prometheus remote write protocol metrics.

Although you can send data from OpenTelemetry instrumentation libraries and SDKs directly to Promscale using OTLP, we recommend that you use OpenTelemetry Collector in a production environment. OpenTelemetry Collector offers batch, queued retries, and many other functions that can be configured in the Processors.

Set the following in OpenTelemetry Collector components in the configuration file:

  • Receivers: to push or pull data into OpenTelemetry Collector using OTLP on gRPC and http endpoints.
  • Exporters: to send data to one or more backends. OTLP to configure the Promscale gRPC server to export the data to Promscale. Use queue_size to hold the data before dropping, and timeout to set the timeout for the write request to the backend. Prometheus remote write exports the OTLP metrics to the Prometheus remote storage backend. Configure the Promscale http endpoint to ingest the metrics.
  • Processors: to run on data between being received and being exported. Use the batch processor to batch, compress data, and control the number of outgoing connections. Configure the send_max_batch_size to set the maximum size of the batch, and timeout to set the time to send data. Promscale recommends 10 seconds.
  • Service: to configure what components are enabled in the Collector based on the settings in the receivers, processors, exporters, and extensions sections. Pipelines to receive the traces and metrics from OTLP, batch process them, and export the data to OTLP gRPC and Prometheus remote-write supported backends.

Use the following configuration to send traces from OpenTelemetry applications to the Collector and export them to Promscale.

endpoint: "<PROMSCALE_HOST>:<gRPC_PORT>"
insecure: true
queue_size: 1000000
timeout: 10s
endpoint: "http://<PROMSCALE_HOST>:<HTTP_PORT>/write"
enabled: true # Convert resource attributes to metric labels
insecure: true
send_batch_size: 4000
send_batch_max_size: 4000
timeout: 10s
receivers: [otlp]
exporters: [otlp]
processors: [batch]
receivers: [otlp]
processors: [batch]
exporters: [prometheusremotewrite]


  • <PROMSCALE_HOST>: hostname of Promscale
  • <gRPC_PORT>: gRPC port of Promscale. The default port is 9202.
  • <HTTP_PORT> : HTTP port of Promscale. The default port is 9201.

If you are running the OTLP Collector and the Promscale Connector on a Kubernetes cluster the endpoint parameter is similar to endpoint: "promscale-connector.default.svc.cluster.local:<PORT>"

The default ports exposed by the OpenTelemetry Collector OTLP receiver are:

  • 4317 : gRPC
  • 4318 : HTTP These are the ports where you should send your OpenTelemetry traces.

The specifics of the configuration are different for each SDK and library. For more information, see the OpenTelemetry documentation.