Data Infrastructure

Kafka consumer fails to process messages due to dimension mismatch

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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

Elasticsearch ReplicaSet scaling failure during benchmarking

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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 air gapped environment

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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

RabbitMQ queue saturation after increasing batch size in ML training

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Problem: RabbitMQ Queue Saturation After Increasing Batch Size in ML Training In a Kubernetes‑deployed distributed training pipeline, the model workers publish gradient‑update messages to a single RabbitMQ queue. After the batch size was raised from 32 to 256, the training loop began to fail with: basic.publish returned: RESOURCE_LOCKED channel flow control activated Message dropped due … Read more

Elasticsearch bulk API batch size exceeded during CI/CD data ingestion

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Elasticsearch Bulk API Batch Size Exceeded During CI/CD Data Ingestion Problem Description During automated model‑training pipelines, a bulk indexing step fails with HTTP 413 or a BulkIndexError. Typical log excerpts include: [2026-06-30T12:14:02,871][ERROR][o.e.b.BulkProcessor] [node-1] request size exceeds the configured limit org.elasticsearch.ElasticsearchException: request size exceeds the configured limit at org.elasticsearch.http.netty4.Netty4HttpChannelHandler.handleRequest(Netty4HttpChannelHandler.java:215) … Caused by: java.lang.IllegalArgumentException: request size exceeds the … Read more

Kafka HPA scaling issues with incorrect CPU metrics

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Problem – Inconsistent Kafka HPA Scaling Due to Mis‑configured CPU Metrics In a Kubernetes‑based telemetry pipeline ingesting IoT sensor data, the Horizontal Pod Autoscaler (HPA) for Kafka consumer pods either adds ~30 % extra replicas during low‑traffic periods or fails to add enough pods during traffic spikes. The symptoms manifest as: Over‑provisioned pods at night, inflating … Read more

Elasticsearch shard rebalancing fails during blue-green deployment

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Problem – Shard Rebalancing Fails During a Blue‑Green Deployment During a zero‑downtime blue‑green swap, the primary cluster (blue) is drained while the secondary cluster (green) is brought online. Operators observed the following symptoms after traffic cut‑over: Repeated log entries such as: [2026-06-27T14:02:13,456][WARN ][cluster.routing.allocation.decider] [node2] failed to allocate shards reason: cluster_state_version mismatch (expected=12345, actual=12340) Cluster health … Read more

PostgreSQL container fails to bind persistent volume claim in K8s

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Problem: PostgreSQL Pod Stalls Because PVC Remains Pending A PostgreSQL container launched by a StatefulSet (or plain Deployment) cannot start. The pod events contain messages such as: Warning FailedMount 12s (x3 over 30s) kubelet MountVolume.SetUp failed for volume “postgres-data” : could not attach or mount volume: failed to find a matching node for volume and the … Read more

Kafka consumer group rebalancing fails during GPU worker restart

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Kafka consumer group rebalancing fails during GPU worker restart Problem Description In a Kubernetes‑based distributed training pipeline, each GPU worker runs a Kafka consumer that streams training batches. When a pod is terminated (pre‑empted, rolling update, or node failure), the consumer group experiences a rebalance that never completes, leading to errors such as: org.apache.kafka.clients.consumer.CommitFailedException: Commit … Read more

RabbitMQ node resource exhaustion in Docker container

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Problem Description In a development sandbox the RabbitMQ node runs inside a Docker container with the default image configuration (1 vCPU, 512 MiB RAM). After a burst of simulated AI‑model‑training orchestration messages the broker becomes unresponsive: Memory usage climbs to >95 % of the container limit. Docker daemon emits OOMKill and restarts the container. CPU spikes to 80‑100 % … Read more