Skip to Main Content

Example: Self-Balancing when Cluster Nodes Change

You can create a Topic with 16 partitions and send a balanced load. When starting and stopping Brokers, observe if partitions are reassigned automatically among different Brokers. This reassignment is a built-in feature of AutoMQ, ensuring automatic self-balancing distribution of data across the cluster. By monitoring the distribution of partitions and the load on Brokers, you can verify if the self-balancing feature works as expected.

After successfully installing AutoMQ using Cluster Deployment on Linux▸, you will get a list of Bootstrap Server addresses similar to the following:

192.168.0.1:9092,192.168.0.2:9092

If you installed it via Deploy Locally▸, the Bootstrap Server addresses will be:

broker1:9092,broker2:9092

In all steps, ensure to replace the Bootstrap Server addresses with the actual addresses you obtained.

Prerequisites​

  • Linux/Mac/Windows Subsystem for Linux

  • Docker

If downloading the container image is slow, refer to Docker Hub Mirror Configuration▸

  • Ensure that the self-balancing feature is enabled for your AutoMQ cluster. If using local deployment mode, this feature is enabled automatically. For other deployment modes, add the parameter --override autobalancer.controller.enable=true when starting the Controller.

Create Topic​


CMD='docker run  --network automq_net  automqinc/automq:latest /bin/bash -c "/opt/kafka/kafka/bin/kafka-topics.sh --partitions 16 --create --topic self-balancing-topic --bootstrap-server broker1:9092,broker2:9092"'; [ "$(uname)" = "Linux" ] && eval "sudo $CMD" || eval $CMD

View Partition Distribution​


CMD='docker run  --network automq_net   automqinc/automq:latest /bin/bash -c "/opt/kafka/kafka/bin/kafka-topics.sh --topic self-balancing-topic --describe --bootstrap-server broker1:9092,broker2:9092"'; [ "$(uname)" = "Linux" ] && eval "sudo $CMD" || eval $CMD


Topic: self-balancing-topic        TopicId: AjoAB22YRRq7w6MdtZ4hDA        PartitionCount: 16        ReplicationFactor: 1        Configs: min.insync.replicas=1,elasticstream.replication.factor=1,segment.bytes=1073741824
        Topic: self-balancing-topic        Partition: 0        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 1        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 2        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 3        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 4        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 5        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 6        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 7        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 8        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 9        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 10        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 11        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 12        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 13        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 14        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 15        Leader: 2        Replicas: 2        Isr: 2

Start the Producer​


CMD='docker run  --network automq_net  automqinc/automq:latest /bin/bash -c  "/opt/kafka/kafka/bin/kafka-producer-perf-test.sh --topic self-balancing-topic --num-records=1024000 --throughput 5120 --record-size 1024 --producer-props bootstrap.servers=broker1:9092,broker2:9092"'; [ "$(uname)" = "Linux" ] && eval "sudo $CMD" || eval $CMD

Start the Consumer​


CMD='docker run --network automq_net  automqinc/automq:1.0.4 /bin/bash -c "/opt/kafka/kafka/bin/kafka-consumer-perf-test.sh --topic self-balancing-topic --show-detailed-stats --timeout 300000 --messages=1024000 --reporting-interval 1000 --bootstrap-server=broker1:9092,broker2:9092"'; [ "$(uname)" = "Linux" ] && eval "sudo $CMD" || eval $CMD

Shutdown Broker​

Shutdown one Broker, causing its partitions to be reassigned to other Brokers. After shutdown, you can observe the recovery of the producer and consumer.


docker stop broker2

When shutting down the broker, you will see the following logs from the producer:


[2024-04-29 05:00:03,436] WARN [Producer clientId=perf-producer-client] Got error produce response with correlation id 49732 on topic-partition self-balancing-topic-7, retrying (2147483641 attempts left). Error: NOT_LEADER_OR_FOLLOWER (org.apache.kafka.clients.producer.internals.Sender)
[2024-04-29 05:00:03,438] WARN [Producer clientId=perf-producer-client] Received invalid metadata error in produce request on partition self-balancing-topic-7 due to org.apache.kafka.common.errors.NotLeaderOrFollowerException: For requests intended only for the leader, this error indicates that the broker is not the current leader. For requests intended for any replica, this error indicates that the broker is not a replica of the topic partition.. Going to request metadata update now (org.apache.kafka.clients.producer.internals.Sender)

After waiting a few seconds, you will see that production and consumption return to normal.


2024-05-07 11:56:08,920] WARN [Producer clientId=perf-producer-client] Received invalid metadata error in produce request on partition self-balancing-topic-3 due to org.apache.kafka.common.errors.NotLeaderOrFollowerException: For requests intended only for the leader, this error indicates that the broker is not the current leader. For requests intended for any replica, this error indicates that the broker is not a replica of the topic partition.. Going to request metadata update now (org.apache.kafka.clients.producer.internals.Sender)
[2024-05-07 11:56:08,920] WARN [Producer clientId=perf-producer-client] Got error produce response with correlation id 42141 on topic-partition self-balancing-topic-3, retrying (2147483646 attempts left). Error: NOT_LEADER_OR_FOLLOWER (org.apache.kafka.clients.producer.internals.Sender)
[2024-05-07 11:56:08,920] WARN [Producer clientId=perf-producer-client] Received invalid metadata error in produce request on partition self-balancing-topic-3 due to org.apache.kafka.common.errors.NotLeaderOrFollowerException: For requests intended only for the leader, this error indicates that the broker is not the current leader. For requests intended for any replica, this error indicates that the broker is not a replica of the topic partition.. Going to request metadata update now (org.apache.kafka.clients.producer.internals.Sender)
[2024-05-07 11:56:08,588] 25693 records sent, 5138.6 records/sec (5.02 MB/sec), 8.9 ms avg latency, 1246.0 ms max latency.
[2024-05-07 11:56:13,589] 25607 records sent, 5120.4 records/sec (5.00 MB/sec), 1.8 ms avg latency, 44.0 ms max latency.
[2024-05-07 11:56:18,591] 25621 records sent, 5121.1 records/sec (5.00 MB/sec), 1.6 ms avg latency, 10.0 ms max latency.

View Partition Distribution again​

After the producer resumes writing, we check the partition distribution again and see that all partitions are distributed on broker1. AutoMQ automatically and quickly completes the reassignment of partitions from the stopped Broker and the self-balancing of traffic.


CMD='docker run --network automq_net  automqinc/automq:latest /bin/bash -c "/opt/kafka/kafka/bin/kafka-topics.sh --topic self-balancing-topic --describe --bootstrap-server broker1:9092,broker2:9092"'; [ "$(uname)" = "Linux" ] && eval "sudo $CMD" || eval $CMD


Topic: self-balancing-topic        TopicId: AjoAB22YRRq7w6MdtZ4hDA        PartitionCount: 16        ReplicationFactor: 1        Configs: min.insync.replicas=1,elasticstream.replication.factor=1,segment.bytes=1073741824
        Topic: self-balancing-topic        Partition: 0        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 1        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 2        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 3        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 4        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 5        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 6        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 7        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 8        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 9        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 10        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 11        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 12        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 13        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 14        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 15        Leader: 1        Replicas: 1        Isr: 1

Restart the broker.

Restart broker2 again to trigger automatic partition reassignment; the producer and consumer can resume after several seconds of retrying.


docker start broker2

At this point, confirm the partition distribution again, and you will see that the partitions have completed automatic reassignment.


Topic: self-balancing-topic        TopicId: AjoAB22YRRq7w6MdtZ4hDA        PartitionCount: 16        ReplicationFactor: 1        Configs: min.insync.replicas=1,elasticstream.replication.factor=1,segment.bytes=1073741824
        Topic: self-balancing-topic        Partition: 0        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 1        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 2        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 3        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 4        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 5        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 6        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 7        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 8        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 9        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 10        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 11        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 12        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 13        Leader: 2        Replicas: 2        Isr: 2
        Topic: self-balancing-topic        Partition: 14        Leader: 1        Replicas: 1        Isr: 1
        Topic: self-balancing-topic        Partition: 15        Leader: 1        Replicas: 1        Isr: 1