Tag
Traces, Tempo and the LGTM stack
I added Grafana's all-in-one otel-lgtm image next to this site's Scala/Play backend: an OpenTelemetry Java agent and Traefik send OTLP to it, Keycloak gates Grafana to one email, and the collector strips query strings. Here is the setup, the guardrails, and what the first traces showed.
Running the box: Docker, Linux, the JVM
My production Postgres publishes no port at all, and I still open it in DBeaver from my laptop. The one-line ssh -L everyone reaches for connects happily and then refuses every query — for a reason that's easy to miss, and eight bytes that prove when you've actually fixed it.
Running the box: Docker, Linux, the JVM
Spring Boot's layered jar extraction splits your dependencies from your code for faster Docker rebuilds. But the mechanism that makes the pieces find each other at runtime isn't Spring at all — it's a JVM rule from 1998.
Wiring Flyway into a Spring Boot 4.1 / Java 25 app with a Docker-Compose Postgres - including the Boot 4 auto-config modularization gotcha that makes a missing starter look exactly like a missing library.
Traces, Tempo and the LGTM stack
Wiring OpenTelemetry into Spring Boot 4 — the annotation way and the manual Tracer way — plus the context model that ties them together and the gotchas that cost me time (a silent @WithSpan, http/protobuf vs gRPC, and Docker's 'is a directory').
Security and privacy, in practice
Five ways to hand a secret to a Docker container, ranked by who can read it back out. The source is just plumbing - environment variable vs file is what actually decides your exposure.