Engineering Logs for Troubleshooting & Debugging
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
Problem: NGINX Ingress Controller PVC Stays Pending After Adding a Logging Volume The NGINX Ingress Controller is deployed via the official Helm chart. After extending the chart to mount a dedicated PersistentVolumeClaim (PVC) for request logging and cache files, the PVC nginx-logging never reaches the Bound phase. The controller pod remains in Pending and the … Read more
Problem: ModelCollection CRD creation returns 422 after Argo CD sync In an on‑premise Kubernetes 1.27 cluster running the KFServing (now KServe) model serving stack, an Argo CD application that contains a ModelCollection manifest fails during the sync phase. The controller logs show a 422 Unprocessable Entity response from the modelcollection.kserve.io admission webhook, with errors such as: admission … Read more
Problem – Batch Ingestion Jobs Fail with Exit Code 1 During Multi‑Region Replication In a production Docker Swarm deployment spanning US‑East, EU‑West and AP‑Southeast, nightly batch ingestion services terminate abruptly with exit code 1. The container logs contain messages such as: failed to connect to remote storage: timeout rpc error: code = Unavailable desc = connection … Read more
Problem Description After a Helm upgrade of the haproxy-ingress chart, the HAProxy pods enter CrashLoopBackOff. The container logs show errors such as: Error opening configuration file /etc/haproxy/haproxy.cfg: No such file or directory MountVolume.SetUp failed for volume “haproxy-config”: configmap “haproxy-config” not found cannot open /etc/haproxy/haproxy.cfg: permission denied failed to reload haproxy: configuration file is not readable … Read more
Kubernetes API server unreachable behind HAProxy after health‑check timeout Problem Description (Symptoms and Impact) During a routine AI inference workload deployment, the control‑plane components (controller‑manager, scheduler, kubelet) began reporting: Failed to connect to apiserver: net/http: request canceled (Client.Timeout exceeded while awaiting headers) HAProxy returned 502 errors to any client trying to reach https://k8s‑lb.example.com: SC– 502 … Read more