Configuration methods

You can change the agent settings in two ways:

• Set an environment variable. For example:

  Linux

  export OTEL_SERVICE_NAME=my-java-app

  Windows PowerShell

  $env:OTEL_SERVICE_NAME=my-java-app

• Add a system property as runtime parameter. For example:

  java -javaagent:./splunk-otel-javaagent.jar \
  -Dotel.service.name=<my-java-app> \
  -jar <myapp>.jar

Environment variables are the preferred way of configuring OpenTelemetry agents. System properties, if specified, override existing environment variables.

General settings

The following settings are specific to the Splunk Distribution of OpenTelemetry Java:

Example of trace sampling

The following example shows how to use the rules traces sampler to exclude the /healthcheck endpoint from monitoring:

export OTEL_TRACES_SAMPLER=rules
export OTEL_TRACES_SAMPLER_ARG=drop=/healthcheck;fallback=parentbased_always_on

All requests to downstream services that happen as a consequence of calling an excluded endpoint are also excluded.

Considerations on trace propagation

For backward compatibility with older versions of the Splunk Distribution of OpenTelemetry Java or the SignalFx Java Agent, use the b3multi trace propagator:

Linux

export OTEL_PROPAGATORS=b3multi

Windows PowerShell

$env:OTEL_PROPAGATORS=b3multi

Instrumentation configuration

The following settings control the instrumentation, including tracing and :

Exporters configuration

The following settings control trace exporters and their endpoints:

The Splunk Distribution of OpenTelemetry Java uses the OTLP http/protobuf span exporter by default. To send data directly to Splunk Observability Cloud, see Send data directly to Splunk Observability Cloud.

Java settings for AlwaysOn Profiling

The following settings control the AlwaysOn Profiling feature for the Java agent:

For more information on AlwaysOn Profiling, see Introduction to AlwaysOn Profiling for Splunk APM.

Server trace information

To connect Real User Monitoring (RUM) requests from mobile and web applications with server trace data, trace response headers are activated by default. The instrumentation adds the following response headers to HTTP responses:

Access-Control-Expose-Headers: Server-Timing
Server-Timing: traceparent;desc="00-<serverTraceId>-<serverSpanId>-01"

The Server-Timing header contains the traceId and spanId parameters in traceparent format. For more information, see the Server-Timing and traceparent documentation on the W3C website.

The following server frameworks and libraries add Server-Timing information:

• Servlet API versions 2.2 to 4.X.

• Netty versions 3.8 to 4.0.

Other settings