Enable OpenTelemetry in the .NET agent

Configure the .NET combined agent to keep reporting to Splunk AppDynamics SaaS while it also sends OpenTelemetry data to Splunk Observability Cloud.

The Splunk AppDynamics .NET combined agent packages the Splunk AppDynamics .NET Agent with the Splunk Distribution of OpenTelemetry .NET, enabling telemetry delivery to both platforms from the same agent instance.

For installation, compatibility, configuration properties, and dual-signal behavior, follow the agent documentation for the installed release. This migration page contains only migration-specific prerequisites, validation, and rollback guidance. Agent documentation provides the source of truth for agent configuration.

Prerequisites

Confirm that:

• The current migration wave includes the .NET application.

• The .NET runtime, operating system, architecture, hosting model, and agent packaging method support the .NET combined agent running in dual-signal mode. The .NET combined agent version 26.5 or higher requires different settings in dual-signal mode than in Splunk AppDynamics mode. In dual-signal mode, its compatibility requirements include:

  • .NET Framework 4.6.2
  • .NET 8.0, 9.0, or 10.0
  • .NET agent frameworks that support OpenTelemetry
  • The combined agent does not support NuGet-based distributions and Azure AppService Extensions.
  Important:

  If your .NET application uses an unsupported runtime, platform, hosting model, or packaging method, do not continue with the combined-agent procedure.

  Workaround: Configure your application to use a supported runtime, platform, hosting model, and packaging method.

• Your environment has a Collector or approved direct-ingest route ready.
• You know the planned values for OpenTelemetry service and resource attributes service.name, service.namespace, and deployment.environment.name.
• You have a maintenance window and representative traffic for validation.

Enable dual-signal mode

1. Enable dual-signal mode using the setting documented for your runtime/packaging/platform. See Enable the combined mode for .NET agent.

2. Implement a telemetry routing scenario.

Verify the agent

1. Generate representative traffic.

2. Verify that every application in the migration wave sends complete, correctly identified telemetry to Splunk Observability Cloud while Splunk AppDynamics monitoring remains available:

   • The application starts normally.
   • The agent startup logs confirm that the Splunk AppDynamics and OpenTelemetry components initialize successfully without persistent configuration, exporter errors, or duplicate OpenTelemetry instrumentation.

   • The application reports data to both destinations during the same time period:

     • In Splunk AppDynamics, the expected application and tier receive current data.
     • In Splunk Observability Cloud, the expected services and their dependencies appear in the Service map, the expected traces receive current data, and the expected identity and resource attributes match the migration plan.

Resolve validation failures

If the validation fails:

1. Confirm that the application process received the combined agent settings.

2. Confirm the selected telemetry route and OTLP endpoint. Confirm that the Collector runs on the configured endpoint.

3. Review the agent and applicable Collector, gateway, or Kubernetes logs.

4. Correct the configuration or route and repeat the validation.

5. Return to the last verified configuration or use the approved rollback procedure if the application becomes unstable.

6. Collect the evidence listed in the selected routing scenario before escalating the issue.

Next step

Record the .NET combined agent version, effective dual-signal setting, selected routing scenario, validation time, and result in the migration-wave record.