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tracing.md

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Learn about the tracing configuration block
stage products
general-availability
oss
tracing

tracing

tracing is an optional configuration block used to customize how {{< param "PRODUCT_NAME" >}} produces traces. tracing is specified without a label and can only be provided once per configuration file.

Usage

tracing {

}

Arguments

You can use the following arguments with tracing:

Name Type Description Default Required
sampling_fraction number Fraction of traces to keep. 0.1 no
write_to list(otelcol.Consumer) Inputs from otelcol components to send traces to. [] no
send_traceparent bool Send traceparent header with requests. false no

The write_to argument controls which components to send traces to for processing. The elements in the array can be any otelcol component that accept traces, including processors and exporters. When write_to is set to an empty array [], all traces are dropped.

{{< admonition type="note" >}} Any traces generated before the tracing block has been evaluated,such as at the early start of the process' lifetime, are dropped. {{< /admonition >}}

The sampling_fraction argument controls what percentage of generated traces should be sent to the consumers specified by write_to. When set to 1 or greater, 100% of traces are kept. When set to 0 or lower, 0% of traces are kept.

The send_traceparent argument controls whether the traceparent header is sent with requests to other services.

Blocks

You can use the following blocks with tracing:

Block Description Required
sampler Define custom sampling on top of the base sampling fraction. no
sampler > jaeger_remote Retrieve sampling information via a Jaeger remote sampler. no

The > symbol indicates deeper levels of nesting. For example, sampler > jaeger_remote refers to a jaeger_remote block defined inside an sampler block.

sampler

The sampler block contains a definition of a custom sampler to use. The sampler block supports no arguments and is controlled fully through inner blocks.

It's invalid to define more than one sampler to use in the sampler block.

jaeger_remote

The jaeger_remote block configures the retrieval of sampling information through a remote server that exposes Jaeger sampling strategies.

Name Type Description Default Required
max_operations number Limit number of operations which can have custom sampling. 256 no
refresh_interval duration Frequency to poll the URL for new sampling strategies. "1m" no
url string URL to retrieve sampling strategies from. "http://127.0.0.1:5778/sampling" no

The remote sampling strategies are retrieved from the URL specified by the url argument, and polled for updates on a timer. The frequency for how often polling occurs is controlled by the refresh_interval argument.

Requests to the remote sampling strategies server are made through an HTTP GET request to the configured url argument. A service=alloy query parameter is always added to the URL to allow the server to respond with service-specific strategies. The HTTP response body is read as JSON matching the schema specified in the Jaeger strategies.json file.

The max_operations limits the amount of custom span names that can have custom sampling rules. If the remote sampling strategy exceeds the limit, sampling decisions fall back to the default sampler.

Example

tracing {
  sampling_fraction = 0.1
  send_traceparent = true

  write_to = [otelcol.exporter.otlp.tempo.input]
}

otelcol.exporter.otlp "tempo" {
  // Send traces to a locally running Tempo without TLS enabled.
  client {
    endpoint = sys.env("TEMPO_OTLP_ENDPOINT")

    tls {
      insecure = true
    }
  }
}