Documentation Grafana Cloud Instrument and send data Traces Metrics-generator in Grafana Cloud Traces

Metrics-generator in Grafana Cloud Traces

The Tempo metrics-generator can derive metrics from traces as they are ingested. When used in Grafana Cloud, the metrics-generator writes metrics directly to the hosted Prometheus instance in the same stack.

For more information about the metrics-generator and the metrics it creates, refer to the metrics-generator documentation.

Enable metrics-generator

Metrics-generation is disabled by default. You can enable it for use with Application Observability defaults in Application Observability, or contact Grafana Support to enable metrics-generation for your organization with custom settings.

Enabling metrics-generator using Application Observability has limitations. By default, Application Observability configures the metrics-generator to only generate metrics for the SERVER and CONSUMER span kinds. Application Observability can be further configured to also generate metrics for CLIENT and PRODUCER span kinds, refer to Include web applications and mobile devices for more details. If you need to generate span metrics for the INTERNAL span kind, contact Support.

Constraints and good to know

• The active series sent to the hosted Prometheus instance is billed like regular metrics.
• Metrics can only be sent to a hosted Prometheus instance in the same region.
• If traces are down-sampled before reaching Tempo, the metrics will be lower than reality.
• All generated metrics are aggregated by default.

Aggregated metrics

Grafana Cloud uses Adaptive Metrics to aggregate away operational labels added by the open source Tempo metrics-generator. This reduces the number of time series produced by the metrics-generator, and therefore reduces the cost of enabling metrics generation for Grafana Cloud users.

In most cases, this aggregation should be completely unnoticeable to users.

If you require unaggregated metrics generated by Grafana Cloud Traces, contact Grafana Support for help removing the aggregation rules from Adaptive Metrics.

Monitor the metrics-generator

The grafanacloud-usage data source exposes several metrics about the metrics-generator.

Amount of active series:

Copy

grafanacloud_traces_instance_metrics_generator_active_series{}

Amount of active series being limited:

Copy

grafanacloud_traces_instance_metrics_generator_series_dropped_per_second{}

Amount of spans that are discarded by the metrics-generator before the spans are processed:

Copy

grafanacloud_traces_instance_metrics_generator_discarded_spans_per_second

This metric has a reason label:

• outside_metrics_ingestion_slack: The time between the creation of the span and when it was ingested was too large and the span is deemed outdated. Processing this span and including it a current metrics sample would skew the data.

How this works

When the amount of active series in Tempo reaches a configurable limit, no new active series are added. Grafana Cloud Traces keeps updating the existing series. The series exceeding the limit are dropped.

Configuration options

You can configure the following settings for metrics-generator in Grafana Cloud Traces. Contact Grafana Support to modify any of these settings.