---
title: Correlate OpenTelemetry Traces and Metrics
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > OpenTelemetry in Datadog > Correlate OpenTelemetry Data > Correlate
  OpenTelemetry Traces and Metrics
---

# Correlate OpenTelemetry Traces and Metrics

## Overview{% #overview %}

Correlating traces with host metrics allows you to pivot from a slow request directly to the CPU and memory metrics of the host or container it ran on. This helps you determine if resource contention was the root cause of a performance issue.

Correlation between traces and metrics relies on the following resource attributes:

- `host.name`: For correlating with host metrics (CPU, memory, disk).
- `container.id`: For correlating with container metrics.

## Requirements{% #requirements %}

Before you begin, ensure you have configured [unified service tagging](https://docs.datadoghq.com/opentelemetry/correlate/#prerequisite-unified-service-tagging). This is required for all data correlation in Datadog.

## Setup{% #setup %}

To correlate traces and metrics, you must:

1. **Collect Host Metrics**: You must have the OpenTelemetry Collector configured to collect and send host metrics to Datadog.

1. **Ensure Consistent Tagging**: Your traces and metrics must share a consistent `host.name` (for hosts) or `container.id` (for containers) attribute for Datadog to link them.

### 1. Collect host metrics

To collect system-level metrics from your infrastructure, enable the `hostmetrics` receiver in your OpenTelemetry Collector configuration. This receiver gathers metrics like CPU, memory, disk, and network usage.

Add the `hostmetrics` receiver to the `receivers` section of your Collector configuration and enable it in your `metrics` pipeline:

```yaml
receivers:
  hostmetrics:
    collection_interval: 10s
    scrapers:
      cpu:
      memory:
      disk:
      ...

service:
  pipelines:
    metrics:
      receivers: [hostmetrics, ...]
      processors: [...]
      exporters: [...]
```

For the complete, working configuration, including Kubernetes-specific setup, see the [Host Metrics](https://docs.datadoghq.com/opentelemetry/integrations/host_metrics) documentation.

### 2. Ensure consistent host and container tagging

For correlation to work, the `host.name` (or `container.id`) attribute on your traces must match the corresponding attribute on the metrics collected by the `hostmetrics` receiver.

## View correlated data in Datadog{% #view-correlated-data-in-datadog %}

After your application is sending traces and the Collector is sending host metrics, you can see the correlation in the APM Trace View.

1. Navigate to [**APM** > **Traces**](https://app.datadoghq.com/apm/traces).
1. Find and click on a trace from your instrumented service.
1. In the trace's flame graph, select a span that ran on the instrumented host.
1. In the details panel, click the **Infrastructure** tab. You should see the host metrics, like CPU and memory utilization, from the host that executed that part of the request.

This allows you to immediately determine if a spike in host metrics corresponds with the performance of a specific request.

## Further reading{% #further-reading %}

- [Send OpenTelemetry Traces to Datadog](https://docs.datadoghq.com/opentelemetry/otel_tracing/)