[jira] [Assigned] (KAFKA-12664) Mirrormaker 2.0 infinite rebalance loop when dealing with more than 2 clusters in standalone mode

["Daniel Urban (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/KAFKA-12664?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Daniel Urban reassigned KAFKA-12664:
------------------------------------

    Assignee: Daniel Urban

> Mirrormaker 2.0 infinite rebalance loop when dealing with more than 2 clusters in standalone mode
> -------------------------------------------------------------------------------------------------
>
>                 Key: KAFKA-12664
>                 URL: https://issues.apache.org/jira/browse/KAFKA-12664
>             Project: Kafka
>          Issue Type: Bug
>          Components: mirrormaker
>    Affects Versions: 2.5.0, 2.4.1, 2.6.0, 2.7.0
>            Reporter: Edward Vaisman
>            Assignee: Daniel Urban
>            Priority: Major
>         Attachments: connect.log.tar.gz, docker-compose-multi.yml, mm2.properties
>
>
> Hi Folks, I came across this issue when trying to aggregate data from two separate data centres into one data centre.
> In the configuration below, you can see I am trying to replicate a topic from dc1 (named test_topic_dc1) to dc3 as well as replicate a topic from dc2 (test_topic_dc2) to dc3.
> However, when I try to replicate both topics from those datacenters at the same time I notice that connect gets stuck in a rebalance loop (see attachment for logs)
>  [^connect.log.tar.gz]
> excerpt of connect.log
> {code:java}
> 2021-04-13 17:03:06,360] INFO [Worker clientId=connect-3, groupId=mm2-dc2] Successfully synced group in generation Generation{generationId=347, memberId='connect-3-c59342c3-ca62-41cc-964c-41a0f98351c0', protocol='sessioned'} (org.apache.kafka.clients.consumer.internals.AbstractCoordinator:756)[2021-04-13 17:03:06,360] INFO [Worker clientId=connect-4, groupId=mm2-dc2] Rebalance started (org.apache.kafka.connect.runtime.distributed.WorkerCoordinator:225)[2021-04-13 17:03:06,362] INFO [Worker clientId=connect-4, groupId=mm2-dc2] (Re-)joining group (org.apache.kafka.clients.consumer.internals.AbstractCoordinator:540)[2021-04-13 17:03:06,368] INFO [Worker clientId=connect-2, groupId=mm2-dc3] Rebalance started (org.apache.kafka.connect.runtime.distributed.WorkerCoordinator:225)[2021-04-13 17:03:06,369] INFO [Worker clientId=connect-2, groupId=mm2-dc3] (Re-)joining group (org.apache.kafka.clients.consumer.internals.AbstractCoordinator:540)[2021-04-13 17:03:06,370] INFO [Worker clientId=connect-3, groupId=mm2-dc2] Joined group at generation 347 with protocol version 2 and got assignment: Assignment{error=1, leader='connect-3-c59342c3-ca62-41cc-964c-41a0f98351c0', leaderUrl='NOTUSED/dc1', offset=13, connectorIds=[MirrorSourceConnector], taskIds=[], revokedConnectorIds=[], revokedTaskIds=[], delay=0} with rebalance delay: 0 (org.apache.kafka.connect.runtime.distributed.DistributedHerder:1688)
> {code}
> To replicate the issue here is what I used:
> [^mm2.properties]
> {code:java}
> clusters = dc1, dc2, dc3
> dc1.bootstrap.servers = kafka-dc1:19092
> dc2.bootstrap.servers = kafka-dc2:19093
> dc3.bootstrap.servers = kafka-dc3:19094
> dc1.group.id=mm2-dc1
> dc2.group.id=mm2-dc2
> dc3.group.id=mm2-dc3
> replication.factor=1
> checkpoints.topic.replication.factor=1
> heartbeats.topic.replication.factor=1
> offset-syncs.topic.replication.factor=1
> offset.storage.replication.factor=1
> status.storage.replication.factor=1
> config.storage.replication.factor=1
> dc1->dc3.enabled = true
> dc1->dc3.topics = test_topic_dc1
> dc2->dc3.enabled = true
> dc2->dc3.topics = test_topic_dc2
> dc3->dc2 = falsedc3->dc1 = false
> {code}
> This [^docker-compose-multi.yml] file to create local kafka clusters (dc1,dc2,dc3)
>  (I set docker to use 6 cpus, 8gb mem, swap 2gb)
> I then ran an interactive shell to run mirror maker within the same docker-compose network (change network to match yours)
> {code:java}
> docker run --network kafka-examples_default -it wurstmeister/kafka:latest bash
> # Upload mm2 properties on server
> /opt/kafka/bin/connect-mirror-maker.sh mm2.properties{code}
> Kafkacat commands to produce to dc1, dc2
> {code:java}
> kafkacat -b localhost:9092 -t test_topic_dc1 -P
> Hello World from DC1!{code}
> {code:java}
> kafkacat -b localhost:9093 -t test_topic_dc2 -P
> Hello World from DC2{code}
> I then tried to remove one of the datacenters to confirm if it was a configuration problem, however mirror maker ran successfully with the below configuration
> mm2.properties
> {code:java}
> clusters = dc2, dc3
> dc2.bootstrap.servers = kafka-dc2:19093
> dc3.bootstrap.servers = kafka-dc3:19094
> dc2.group.id=mm2-dc2
> dc3.group.id=mm2-dc3
> replication.factor=1
> checkpoints.topic.replication.factor=1
> heartbeats.topic.replication.factor=1
> offset-syncs.topic.replication.factor=1
> offset.storage.replication.factor=1
> status.storage.replication.factor=1
> config.storage.replication.factor=1
> dc2->dc3.enabled = true
> dc2->dc3.topics = test_topic_dc2
> {code}
> Any help would be appreciated!



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