Blog

ClickHouse LowCardinality cuts storage and speeds up queries on low-cardinality columns, but backfires on trace IDs. How to tell the difference.

Drop a JAR on the JVM. Get distributed tracing, RxJava context propagation, log-trace correlation, and Vert.x internal metrics. No code changes. No Maven dependency. Java 8–21. Inside the design of last9/vertx-opentelemetry v2.3.4.

What actually works for Kubernetes monitoring at scale — not what looks good in a vendor demo with a five-pod cluster.

Why ECS containers collapse under service.name = aws_ecs and how to fix it for both EC2 launch type and Fargate, including the resource-vs-log-record pitfall that quietly breaks log filtering.

LocalStack lets you run SQS, Lambda, and S3 locally in Docker — but there's a hidden trap: OpenTelemetry's default AWS propagator doesn't work with free LocalStack. Here's how to set up end-to-end local testing with working trace propagation.

SQS doesn't propagate trace context automatically. You instrument both sides, deploy, and get two disconnected traces. This post shows how to wire them into one waterfall — and the ESM format gotcha that silently breaks it every time.

OpenTelemetry's GenAI instrumentation gives you spans and token counts. It does not give you conversations, workflow cost rollups, or prompts visible in your dashboard. last9-genai is an OTel extension that fills those three gaps — without replacing your existing observability stack.

Health check endpoints generate thousands of identical, useless spans per day. Here are two production-ready approaches to filter them from your Python OTel traces — and the correctness trap most implementations miss.