Engineering Logs for Troubleshooting & Debugging
Problem – OAuth2 Token Request Timeout After Docker Restart After a Docker daemon restart on a node, pods that host the AI inference service begin to fail during the OAuth2 token acquisition phase. The service logs show repeated timeouts when contacting the authorization server, and the authentication flow aborts, causing inference requests to return 401 … Read more
Problem During model evaluation, client applications send audio files to the inference endpoint. When the request passes through the Nginx reverse proxy, the service returns 502 Bad Gateway and the audio payload received by the inference service is corrupted (truncated or contains null bytes). The symptom appears only when Nginx is in the request path; … Read more
Problem – Docker Inference Container OOM After Batch Size Overflow In a micro‑services architecture each AI inference service runs inside its own Docker container. Under normal load the service batches incoming requests (e.g., 16 images) and runs a single forward pass on the model. When a traffic spike or a mis‑configured batcher allows the queue … Read more
Problem Description In a cloud‑managed deployment the Retrieval‑Augmented Generation (RAG) service began returning unrelated documents. The downstream application logged an “Embedding dimension mismatch” error and occasional 502 Bad Gateway responses such as: 2024/09/20 12:34:56 [error] 27#27: *1023 upstream prematurely closed connection while reading response header from upstream, client: 10.2.3.45, server: rag-api.example.com, request: “POST /embed HTTP/1.1”, … Read more
Problem – Model‑Serving Pods Cannot Reach Redis Cache In a production Kubernetes cluster the AI inference workloads run in the model-serving namespace. The Redis cache that stores model artifacts lives in the data-services namespace and is exposed via the Service redis-data-services (port 6379). After a recent deployment of a default‑deny NetworkPolicy in model-serving, inference requests … Read more
Problem – RAG pipeline returns empty retrieval after Docker container restart in Kubernetes Symptom: After a pod restart (e.g., rolling update, node‑drain, or container crash) the Retrieval‑Augmented Generation (RAG) service answers every query with No documents retrieved or an empty list, even though the knowledge base was populated before the restart. Typical log excerpt: 2024-09-15 … Read more
Problem Description A real‑time LLM streaming service proxies requests through Nginx (HTTP/2). When the model generates responses that exceed a few kilobytes of token data, the client receives a truncated stream and the Nginx error log contains entries such as: 2026/09/13 12:45:27 [error] 12#12: *12345 client intended to send too large body, request body size … Read more
Problem Description During automated model evaluation runs in a CI/CD pipeline on a Kubernetes cluster, the Retrieval‑Augmented Generation (RAG) microservice returns an answer field that is either empty or malformed. The API response typically looks like: { “question”: “What is the capital of France?”, “answer”: “” } Typical log excerpts from the RAG pod include: … Read more
Intermittent 502/504 OAuth2 Token Errors Behind HAProxy in Kubernetes Problem Description In a production GKE data‑pipeline, several microservices acquire an OAuth2 access token from an internal /token endpoint. The endpoint is exposed through a HAProxy Ingress controller. Under normal load the token exchange succeeds, but during rolling updates, high‑load spikes, or after pod eviction the … Read more
Problem – Model Weight Synchronization Lag Behind Nginx Load Balancer In a staging environment we run three Docker‑based inference replicas behind an Nginx upstream. Model artifacts are stored on a shared NFS mount and are updated by a CI/CD pipeline that copies a new .pt file into /models. After each deployment the expectation is that … Read more