Kafka Consumer Group Constantly Rebalancing

Symptom

Logs full of "Rebalance in progress"; lag grows; processing stalls.

Consumers miss the heartbeat or take too long between polls.

1. Check max poll interval vs real processing timemax.poll.interval.ms # default 5m

2. Tune the session for your networksession.timeout.ms=15000, heartbeat.interval.ms=3000

3. Cut restart churn with static membershipgroup.instance.id=<stable-id> # Kafka 2.3+

Keep poll loops fast; heavy work goes to a queue sink, not the consumer thread.

Spinning up a fresh box to reproduce or escape this error?

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Last reviewed 2026-10-02 · NinjaOps SEO grid · DevOps blog