group.instance.id — Kafka Consumer Configuration
A unique identifier of the consumer instance provided by the end user. Only non-empty strings are permitted.
Description
A unique identifier of the consumer instance provided by the end user. Only non-empty strings are permitted. If set, the consumer is treated as a static member, which means that only one instance with this ID is allowed in the consumer group at any time. This can be used in combination with a larger session timeout to avoid group rebalances caused by transient unavailability (e.g. process restarts). If not set, the consumer will join the group as a dynamic member, which is the traditional behavior.
Default Values by Kafka Version
| Kafka Version | Default Value |
|---|---|
| 2.3 | null |
| 2.4 | null |
| 2.5 | null |
| 2.6 | null |
| 2.7 | null |
| 2.8 | null |
| 3.0 | null |
| 3.1 | null |
| 3.2 | null |
| 3.3 | null |
| 3.4 | null |
| 3.5 | null |
| 3.6 | null |
| 3.7 | null |
| 3.8 | null |
| 3.9 | null |
| 4.0 | null |
| 4.1 | null |
| 4.2 | null |
Tuning Recommendation
| Profile | Recommended | Why |
|---|---|---|
| consumer / throughput | <unique-per-instance-id> | Setting a stable group.instance.id enables static group membership: when a consumer restarts, the broker recognizes it by ID instead of treating it as a new member, skipping the rebalance entirely during the session.timeout.ms window. Critical for high-throughput pipelines where rebalances cause seconds of total-group processing interruption. |
| consumer / durability | <unique-per-instance-id> | Static membership eliminates the rebalance triggered by consumer restarts. When a durable consumer restarts (e.g., after processing an error), the broker recognizes its stable ID and does not trigger a full group rebalance within session.timeout.ms. This prevents the duplicate-processing burst that rebalances cause in at-least-once consumers. |
Related Configs
partition.assignment.strategy · session.timeout.ms · max.poll.interval.ms
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