What is observability? Logs, metrics, and traces explainedObservability is the ability to infer a system's internal state from its external outputs. Learn how the three pillars — logs, metrics, and traces — work together, the difference between monitoring and observability, and the four golden signals (latency, traffic, errors, saturation).What is a canary deployment? How canary releases work and when to use themA canary deployment rolls out a new version to a small subset of users first, then gradually expands if metrics stay healthy. Compare canary vs rolling update vs blue-green, learn the metrics to watch, and see when this progressive-delivery pattern fits your team.How to monitor a Node.js application with Prometheus and GrafanaBuild a complete Node.js + Prometheus + Grafana monitoring stack: instrument Express with prom-client, scrape metrics, run Prometheus in Docker, build Grafana dashboards with PromQL, and configure alerts. Includes a working docker-compose example. 