Engineering Logs for Troubleshooting & Debugging
Problem – Latency Spike in Kubernetes‑Hosted AI Inference Service During peak traffic windows the inference endpoint that serves ~100 ms predictions suddenly starts responding in 1 s +. The spike is repeatable, lasts for the duration of the load burst, and then returns to baseline once traffic subsides. Key observations: CPU and memory usage on GPU‑accelerated pods stay … Read more
Problem Description In a Docker‑based AI training workload orchestrated by Kubernetes, a ReplicaSet that should run multiple pods—each requesting a set of GPUs—stops scaling after the first replica. The cluster has sufficient free GPUs (e.g., a node with 8 × NVIDIA A100), but subsequent pods remain in Pending with scheduler messages such as: 0/5 nodes are available: 5 … Read more
Problem – HAProxy NodePort Conflict in Kubernetes Staging In the staging environment several AI micro‑services expose a NodePort service. The HAProxy ingress controller attempts to bind each service’s NodePort on the host network interface. When two or more services request the same port, HAProxy pods repeatedly fail to start with errors such as: 2024-06-23T10:12:45Z haproxy[1]: … Read more
Problem – HAProxy reload fails with “invalid function call format” During automated deployments in a GitLab CI pipeline the HAProxy service aborts its reload step. The CI job reports a validation error such as: ERROR: configuration file contains an invalid function call format at line 42 parse error: unexpected token ‘(‘ in fetch expression Invalid … Read more
Problem – HAProxy Context Window Overflow During ML Training Loop In a Kubernetes‑based distributed training pipeline, dozens of GPU worker pods issue HTTP GET/POST requests to a shared model storage service through an HAProxy ingress. During hyper‑parameter sweeps and large batch fetches the following symptoms were observed: HAProxy logs repeatedly contain tune.bufsize exceeded, context window … Read more
Problem Description During a sustained load test of a Docker‑containerized language model serving endpoint, the logprob values returned by the PyTorch model became inconsistent. Under low traffic the model produced deterministic log‑softmax outputs, but at peak rates (≈200 RPS) the following symptoms were observed: Log probabilities drifted by up to 0.12 nats between identical inputs. Intermittent errors … Read more
Problem – Validation Errors After Updating a CRD Schema After a recent schema change to a shared Custom Resource Definition (CRD) used by multiple AI/ML services, kubectl apply and CI/CD pipelines began failing with errors such as: error: admission webhook “v1.crdvalidation.k8s.io” denied the request: spec: Required value Other observed messages include: validation failed: spec.replicas: Invalid … 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 The data‑pipeline service, defined in a docker‑compose.yml file, attempts to call the API server at http://api:5000/api during ingestion. The call consistently fails with either a timeout or a connection‑refused error, causing the pipeline to abort. Typical log excerpts: pipeline | 2026-06-12T08:14:32Z ERROR: dial tcp 172.18.0.3:5000: connect: connection refused pipeline | 2026-06-12T08:14:32Z ERROR: Get … Read more
Problem – HAProxy traffic imbalance during a blue‑green deployment During a scheduled blue‑green rollout of a new service version, the production HAProxy 2.8 front‑end observed a ~40 % increase in query latency. The spike appeared only after the first batch of green servers was added to the blue_green backend and persisted until the rollout completed. Typical … Read more