Engineering Logs for Troubleshooting & Debugging
Problem Description The inference API service, built with FastAPI and using psycopg2/SQLAlchemy to query a PostgreSQL instance, started returning HTTP 504 timeouts after a recent firewall rule change. The API logs contain repeated connection errors such as: 2026-08-31 14:02:13,842 ERROR inference.api.handlers – could not connect to server: Connection timed out (0.00s) Is the server running … Read more
Problem – Canary Elasticsearch Pods Time Out After Calico NetworkPolicy Change During a canary rollout of a new Elasticsearch version, pods labeled app=es-canary were unable to reach the primary elasticsearch-master service. All HTTP requests to port 9200 and transport requests to port 9300 resulted in connection‑timeout errors, causing indexing and query failures and halting the … Read more
Problem: Intermittent Redis Pub/Sub Streaming Interruptions in AI Inference Staging The AI inference service streams tokenized responses to clients via a Redis Pub/Sub channel. In the staging environment the stream is occasionally truncated, causing the client to receive incomplete answers or a sudden “connection closed” error. The symptom manifests as: Log entry: socket.timeout: timed out … Read more
Problem – Redis pod stuck pending PVC on an edge node after node reboot A Redis StatefulSet deployed to an edge‑computing node fails to start. The pod remains in Pending because its PersistentVolumeClaim (redis-data) never becomes Bound. The symptom blocks data persistence and makes the Redis service unavailable. Typical pod description: kubectl describe pod redis-0 … Read more
Problem: Elasticsearch pod placement failures under high‑concurrency load testing During automated benchmark runs that combine Elasticsearch Rally suites with custom ML vector‑search latency tests, the Kubernetes scheduler repeatedly emits FailedScheduling events and refuses to bind new Elasticsearch pods. The observable symptoms include: Pod events such as “FailedScheduling: 0/5 nodes are available: 5 Insufficient cpu” and … Read more
Problem – OOM and CPU Saturation Under Concurrent Vector Search & Embedding Ingestion In a production Retrieval‑Augmented Generation (RAG) service the Elasticsearch cluster receives >15 k requests / second. Each request either: Executes a k‑nn similarity search on a dense_vector field. Streams newly generated embeddings via bulk indexing. During peak traffic the following symptoms appear on the hot … Read more
Problem Description During development of an AI training pipeline on Docker Desktop’s integrated Kubernetes cluster, the PostgreSQL pod that stores experiment metadata and feature‑store data fails to start. The pod repeatedly enters CrashLoopBackOff and the container logs contain errors such as: 2024-07-15 10:12:34.567 UTC [1] LOG: could not open configuration file “/etc/postgresql/conf.d/custom.conf”: Permission denied 2024-07-15 … Read more
Problem Description After an automatic disaster‑recovery (DR) failover to the secondary cloud region, AI training workers were unable to publish messages to RabbitMQ. The broker logged repeated authentication failures with the SAML plugin: 2024-07-31 12:04:18.732 [error] {rabbit_auth_backend_saml, handle_authentication_failure, [{error, “SAML assertion is expired”}, {error, “SAML assertion not yet valid”}, {error, “Invalid SAML audience”}, {error, “Signature … Read more
Problem Description During peak AI inference traffic, Kafka consumer pods in a Kubernetes cluster begin to terminate with the following errors: java.lang.OutOfMemoryError: Java heap space at org.apache.kafka.clients.consumer.internals.Fetcher.fetchRecords(Fetcher.java:267) at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1152) … java.lang.OutOfMemoryError: Direct buffer memory at java.nio.Bits.reserveMemory(Bits.java:698) at java.nio.DirectByteBuffer.(DirectByteBuffer.java:112) at org.apache.kafka.common.record.MemoryRecordsBuilder.(MemoryRecordsBuilder.java:124) … [Consumer clientId=consumer-1, groupId=feature-stream] Failed to allocate memory for record batch Operational impact includes: Consumer … Read more
Problem Description After a routine update to the Retrieval‑Augmented Generation (RAG) pipeline, the citation extraction step began returning malformed JSON objects. Downstream the LLM serializer throws errors such as: JSON parsing error: Unexpected token ‘}’ at position 127 ERROR: invalid input syntax for type jsonb Observed symptoms in production logs: API responses missing source_id fields … Read more