Metrics tell you that something is wrong. Traces tell you where. Logs tell you why. Use them in that order and each step narrows the search — start with logs and you are grepping a firehose. Here is what each one is actually for, and the field that connects all three.
Put a CDN in front of a dynamic site carelessly and it will cache one user's personalised page and serve it to everyone — invisibly, because your logged-in browser looks fine. Here is how to classify routes, set cache headers that hold, and run the two curl commands that catch the leak.
The top search result tells you to run docker system prune -a --volumes. It frees the space and deletes your database. Here is how to measure Docker disk usage properly, reclaim it from safest to most destructive, and fix the logs that Docker never reports on.
Almost every TLS certificate error traces back to one of three causes: a broken chain, a hostname the certificate does not cover, or an expiry nobody was watching. Here is how to tell them apart in under a minute, and how to stop the third one from ever happening again.
Docker containers rarely fail without leaving clues. This practical guide explores common Docker issues involving networking, storage, permissions, ports, logs, health checks, reverse proxies, and resource usage—and explains how to troubleshoot them methodically.