In case of disabled AWS Tracing (X-ray) spans are not sent about aws-otel-lambda

[wangzlei]

Thanks for raising this question, the current OTel Lambda design is:

1. Check trace id from env variable _X_AMZN_TRACE_ID. if sample flag in _X_AMZN_TRACE_ID is 1, export span to collector;
2. If sample is 0, try to parse trace id from http header by other propagators.

This logic respects parent, here the parent is Lambda service. If disable tracing and no context propagation, sample would be 0, OTel SDK in Lambda sandbox does not export span.
Referring OTel spec sampler, that is because by default using ParentBased. So, you can set sampler to AlwaysOn or TraceIdRatioBased to ignore parent.

[mat-rumian]

I think we can close this issue. Setting OTEL_TRACES_SAMPLER=always_on is solving the problem.