Engineering Logs for Troubleshooting & Debugging
Problem Description After a rolling update of a Deployment in a Kubernetes cluster, the NGINX Ingress controller started returning 502 Bad Gateway and 504 Gateway Timeout for the affected host. The HTTP response body was empty, and the NGINX error log contained entries such as: 2024/07/31 12:45:12 [error] 12#12: *12345 connect() failed (111: Connection refused) … Read more
Problem Description During a traffic surge on a high‑volume API gateway powered by Nginx Plus, the following symptoms were observed: Intermittent 502 Bad Gateway responses. HTTP 500 payloads containing the phrase invalid sampling parameter. NGINX error log entries such as: 2024/01/15 10:23:41 [error] 1123#1123: *4567 configuration file /etc/nginx/conf.d/api.conf test failed: invalid sampling_rate 1.5, allowed range is … Read more
Problem: Nginx Fails to Bind Because a Node.js Process Holds the Desired Port In an air‑gapped deployment the nginx service is started after a Node.js micro‑service that is configured to listen on the same TCP port (commonly 80 or 443). Because the environment has no internet connectivity, developers cannot pull remote debugging tools or replace … Read more
Problem – Nginx Serves Stale Data After a Kubernetes Pod Update In an on‑premises data‑center, Nginx (or the Nginx Ingress Controller) is used as a reverse proxy for a micro‑services architecture. Service endpoints are discovered through the Kubernetes EndpointSlice API. After a rolling update or a pod crash, Nginx continues to forward traffic to the … Read more
Problem – Tokenizer Encoding Errors Behind an Nginx Reverse Proxy During automated model deployment in a CI/CD pipeline (GitLab CI, Jenkins, Azure DevOps, or GitHub Actions), the inference service receives POST requests containing raw text that must be tokenized. In several incidents the service raised exceptions such as: UnicodeDecodeError: ‘utf-8’ codec can’t decode byte 0x80 … Read more
Problem Description During multi‑GPU training jobs running in a Kubernetes cluster, webhook callbacks that report progress to an external observability platform (e.g., Datadog, Prometheus remote‑write) start failing after a few minutes of computation. The Nginx ingress controller logs errors such as: [error] 12345#0: *6789 upstream timed out (110: Connection timed out) while reading response header … Read more