Key things

OTLP

  • The default network port for OTLP/gRPC is 4317 - http://localhost:4317 and grpc
  • The default network port for OTLP/HTTP is 4318 - http://localhost:4318 and http/protobuf or http/json

Terms of art

Sampling is the term that describes sending a subset of your traces to your observability backend, perhaps to save costs, filter out noise or only send traces that are interesting to you:

  • Head-based sampling is “where the sampling decision is made at the beginning of a request when the root span begins processing”
  • Tail sampling is “where the sampling decision is made after all the spans in a request have been completed”