Tech Simulators / Kafka

Consumer Rebalance Simulator

Understand how Kafka assigns partitions to consumers using different assignors

Learn Kafka (Full Bootcamp)
Configuration
Adjust topic and consumer group settings to trigger rebalances

Note: Partitions can only be increased, not reduced in Kafka

Cooperative Sticky Assignor

Instead of 'stop everything → revoke all → reassign', it does 'revoke only what is needed → gradual reassignment'.

Zero-downtimeKIP-429Use in production
Rebalance Status

Partitions

6

Consumers

2

Rebalance Count

0

Consumer-Partition Assignment
Shows which partitions are assigned to each consumer. A partition can only be assigned to ONE consumer at a time.
Rebalance Event Log

No rebalance events yet. Try adding/removing consumers or partitions.

Assignor Comparison

Range Assignor

  • All partitions across topics are flattened
  • Then assigned one-by-one in circular fashion

Round Robin Assignor

  • All partitions across topics are flattened
  • Then assigned one-by-one in circular fashion

Sticky Assignor

  • First: balances partitions evenly
  • Then: retains previous assignments

Cooperative Sticky Assignor

  • Revoke only what is needed → gradual reassignment
  • Instead of stop everything → revoke all → reassign
Master Kafka end-to-end — Core Kafka Bootcamp with hands-on labs →