datadog.yaml

apm_config:
  # This points the `trace-agent` at Vector's `datadog_agent` source.
  apm_dd_url: http://localhost:8081
  
  # Set these to zero in order to avoid the Datadog Agent sampling traces before sending
  # them to Vector, which will skew computed statistics like request count, or success vs
  # error span count, etc.
  max_traces_per_second: 0
  errors_per_second: 0

vector.yaml

sources:
  dd_agent:
    type: datadog_agent
    address: "[::]:8081"
    multiple_outputs: true
    trace_proto: v1v2

sinks:
  dd_trace:
    type: datadog_traces
    inputs:
     - dd_agent.traces
    default_api_key: "YOUR_DD_API_KEY_HERE"