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daily-triage/kafka-consumer-progress-stalls-brokers-available.md
Daily Triage Briefing

Kafka Consumer Progress Stalls While Brokers Remain Available

Impact Summary

A fictional Apache Kafka workflow tests how to distinguish broker availability from end-to-end consumer progress, select a bounded investigation and define safe recovery checks without assuming a live incident.

SeveritySEV-2
StatusResolved simulation
PlatformDistributed Systems
Incident TypeDistributed Systems
Published12 Sept 2026
Technologies Involved
Apache Kafka

Simulation Label

Fictional simulation. This exercise is a bounded, invented training scenario for practising operational reasoning. No real organisation, incident, telemetry, credentials or production identifiers are involved or implied.

Operational Summary

Root Cause

Within the fictional reveal, application processing exceeds the workflow's allowed interval after a deployment, leaving the consumer group running but preventing timely committed-offset progress.

Detection Method

Evidence-led guided investigation

Current Status

Resolved simulation

Affected Services

Apache Kafka

Incident Overview

A platform team operates a fictional order-processing workflow. Producers write records to an Apache Kafka topic, and one consumer group turns those records into downstream status updates.

At 10:00, users begin seeing delayed updates. The incident is assessed as fictional SEV-2 because processing is materially delayed, although ingestion remains available.The broker availability check is healthy, producer acknowledgements continue, and the topic's newest offsets rise.

Consumer instances are running, but completed status updates stop advancing. A deployment occurred shortly before the symptom, yet application logs contain both successful poll messages and repeated processing-time warnings.

The apparently healthy brokers conflict with the stalled business outcome.

Investigation Options

Review the available operational moves and select the best immediate action.

A

Inspect the affected consumer group's assignment, state, committed offsets and lag using a version-appropriate, read-only Apache Kafka administrative interface.

B

Inspect broker health more deeply because successful broker checks may conceal a broker outage.

C

Wait for another observation window without collecting additional evidence because the consumer processes are still running.

D

Escalate immediately to the application owner with the existing evidence and request no further technical inspection.

Tags:Apache Kafka