Foundations
What observability is for, how OpenTelemetry is put together, the Grafana LGTM stack, and getting the tooling in place before any code is instrumented.
Outline
What this tutorial covers, the five-signal map, the three language stacks, and how to read the chapters that follow.
Why observability
Monitoring answers the questions you planned for; observability answers the ones you didn't, and why that distinction is worth a new vocabulary.
OpenTelemetry architecture
API versus SDK versus instrumentation, Resource and Context and Propagation, and the Collector's role between a process and its backend.
The LGTM stack
Loki, Grafana, Tempo, and Mimir, plus Pyroscope and the embedded OTel Collector: what each store holds, the all-in-one image, and the ports every later chapter uses.
Prerequisites and setup
SDKMAN and uv toolchains for Spring Boot, Quarkus, and Python, bringing up the shared LGTM stack with podman compose, and the devcontainer/Testcontainers path for day-to-day development.