Engineering Logs for Troubleshooting & Debugging
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
Problem – Consumer Crashes on Embedding Dimension Mismatch In a staging deployment of an AI inference pipeline (Kafka 3.3 brokers, Confluent Schema Registry 7.x), the downstream consumer that reads nlp-embeddings messages began throwing SerializationException and shutting down its poll loop. The failure manifested as: org.apache.kafka.common.errors.SerializationException: Size of data 3072 does not match expected fixed size 2048 for … Read more
Problem: Replica Set Scaling Failure During Elasticsearch Benchmarking During a performance benchmark on a multi‑node Elasticsearch cluster, replica shards do not scale up or down in response to the predefined desired replica count metrics. The symptoms observed include: After adding two new data nodes, replica shards remain on a single node, causing CPU saturation on … Read more
PostgreSQL Streaming Query Interrupted Mid‑Execution in an Air‑Gapped Environment Problem Description An AI inference service running inside a sealed laboratory network streams large SELECT result sets from PostgreSQL using a custom asynchronous Python client. During execution the client receives only a partial set of rows and then the connection is terminated. Typical symptoms include: Log … Read more