OpenTelemetry

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”

Lambdas/serverless

opentelemetry-lambda:

• See https://github.com/open-telemetry/opentelemetry-lambda/releases
• ARNs like:
  • arn:aws:lambda:<region>:184161586896:layer:opentelemetry-javaagent-0_17_0:1
  • arn:aws:lambda:<region>:184161586896:layer:opentelemetry-nodejs-0_19_0:1
  • arn:aws:lambda:<region>:184161586896:layer:opentelemetry-collector-<amd64|arm64>-0_12_0:1 (a stripped-down version of OTel Collector inside an AWS Extension Layer)

ADOT (AWS Distribution of OpenTelemetry):

• ADOT is a downstream repo of opentelemetry-lambda
• AWS-managed OpenTelemetry Lambda layers that are preconfigured for use with AWS services and bundle the reduced ADOT Collector
• ARNs like:
  • arn:aws:lambda:ca-central-1:901920570463:layer:aws-otel-nodejs-amd64-ver-1-18-0:1 - “legacy” layer which includes an embedded collector.
  • arn:aws:lambda:eu-central-1:615299751070:layer:AWSOpenTelemetryDistroPython:21 - new-style layer which works with CloudWatch only.

grafana/collector-lambda-extension:

• Custom distribution of the opentelemetry-lambda collector layer, built for Grafana Cloud
• Designed to be used in conjunction with an opentelemetry-lambda instrumentation layer, like arn:aws:lambda:<region>:184161586896:layer:opentelemetry-nodejs-0_19_0:1
• ARNs like:
  • arn:aws:lambda:eu-west-2:050451360540:layer:opentelemetry-collector-grafana-arm64-v0_138_0:2