Topic
The practice of diagnosing and resolving unexpected failures in live production systems, spanning crashes, networking, concurrency, and state-sync bugs.
A developer canceled his own subscription in production, collected two 200 webhook responses and no errors, and still saw his app promise a renewal. Stripe's stored event diff named the three fields that actually moved.
Reality
A traveller published 178 trip reports at once. The queue in front of the model got through them on ids alone at ten jobs a minute, with one five-minute lease column covering both retries and dead workers.
Reality
A coturn install on Debian can report active, bind nothing, and log no error. A dev.to walkthrough therefore puts two browser checks ahead of any config edit, so you stop fixing a relay that already works.
Reality
Signaling rides TCP 443 through the infrastructure you already configured. The media is UDP that bypasses the proxy entirely, and on a NATed cloud VM the server advertises a private address until you configure the public one yourself.
Reality
A rolling deploy kept serving deleted JSON fields to a slice of traffic while stickiness was switched off in the balancer config, and the connection doing it was an idle socket held by a module-level requests.Session.
Reality
On a kind cluster where kube-proxy was never installed, Cilium 1.17.3 forwards Services with no KUBE-SERVICES chain at all, so the grep that returns 13 rules elsewhere returns nothing while the app stays up.
Reality
For months a nightly job processed the same batch twice, always within fifteen minutes of a deployment. The author of a dev.to field note spent 48 hours suspecting the broker before checking which process the pidfile named.
Reality
Najeeb Ullah traces intermittent SocketExceptions in an ASP.NET Core payments service to connection lifecycle, where each per-request client gets its own pool and each close parks a local port in TIME_WAIT while CPU, memory and database graphs stay flat.
Reality
A dev.to engineer went back to the logs of an agent and found the same three steps on every run. That pattern argues for the fixed-pipeline rewrite the post reports, though the post carries no numbers to size it.
Reality
The Cloud Console showed four green steps and the Management API called the runtime ACTIVE, while the forwarding VMs had no identity to fetch their startup script and no endpoint to forward to, so the only check that found the fault was a request.
Reality
Kubernetes calls it OOMKilled. Linux calls it overcommit coming due, and a badness score nobody in the deploy pipeline has looked at decides who pays.
Reality