[BUG] AddAzureMonitorTraceExporter clobbers the trace sampler about azure-sdk-for-net

[mol-pensiondk]

Maybe the more usual path is to replace Application Insights libraries with OT and use the Azure Monitor exporter from the outset rather than going with the OT Collector first, and that is why the issue has not been discovered/reported before. Or maybe it is because the default OT sampler samples all root activities, so replacing it with a sampler that samples all activities (ignoring parent context) will generate the same telemetry in many applications. It's only when you actually care about not setting the W3C recorded flag too often (and respecting the flag if set in the context) that you will really notice.

It's a shame that the clobbering behaviour cannot be changed. But at least with updated documentation, the next team trying to figure out why sampling policy is not respected will have a chance of doing so more quickly.

[github-actions]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @cijothomas @rajkumar-rangaraj @reyang @TimothyMothra @vishweshbankwar.

[cijothomas]

This is unfortunate, but since the library is already stable, the behavior cannot be changed. All we can do is to ensure the doc is pretty clear on what are the effects of calling AddAzMonExporter, so users can take precaution and workarounds.