MirrorMaker2 connectors get ConnectionRestException

[AvihuHenya]

Strimzi: 0.19.0
Kafka: 2.4.0
KafkaConnect: 2.4.0
KafkaMirrorMaker: 2.4.0

Hi all. I have encountered some problems when I have tried to deploy KafkaMirrorMaker2 instance to migrate data between 2 Kafka clusters. When applying the resource, I get error message regarding the 3 connectors related to the MirrorMaker (sourceConnector, checkpointConnector, heartbeatConnector).

The error message is:
GET
/connectors/source-cluster->target-cluster.MirrorCheckpointConnector/config returned 500 (Internal Server Error): Request timed out

and so for the 2 other connectors:
/connectors/source-cluster->target-cluster.MirrorSourceConnector/config
/connectors/source-cluster->target-cluster.MirrorHeartbeatConnector/config

KafkaMirrorMaker2 Yaml:

apiVersion: kafka.strimzi.io/v1alpha1
kind: KafkaMirrorMaker2
metadata:
  namespace: strimzi
  name: my-mirror-maker-2
spec:
  version: 2.5.0
  replicas: 1
  connectCluster: "my-target-cluster"
  clusters:
  - alias: "my-source-cluster"
    bootstrapServers: my-cluster-kafka-bootstrap.strimzi.svc.cluster.local:9092
  - alias: "my-target-cluster"
    bootstrapServers: my-target-kafka-bootstrap.strimzi.svc.cluster.local:9092
    config:
      config.storage.replication.factor: 1
      offset.storage.replication.factor: 1
      status.storage.replication.factor: 1
  mirrors:
  - sourceCluster: "my-source-cluster"
    targetCluster: "my-target-cluster"
    sourceConnector:
      config:
        replication.factor: 1
        offset-syncs.topic.replication.factor: 1
        sync.topic.acls.enabled: "false"
    heartbeatConnector:
      config:
        heartbeats.topic.replication.factor: 1
    checkpointConnector:
      config:
        checkpoints.topic.replication.factor: 1
    topicsPattern: ".*"
    groupsPattern: ".*"

[scholzj]

Sorry, but where do you get the message? In some logs? In curl when you try to list them on your own?

[scholzj]

Well, as I said, if you run them in parallel you should make sure to use different topic names etc. for them. Otherwise they conflict with each other.

[AvihuHenya]

I've tried changing the MirrorMaker topic names using the config.offset/config/status.storage.topic properties, any other topic has the source cluster alias appended to it (no IdentityReplicationPolicy), so there are no topics with the same name, yet it still happens.
Also, the error doesn't seem to be related to the topics..

[scholzj]

Also, the error doesn't seem to be related to the topics..

Well, the error suggests that the underlying connect cluster does not work well. That might and might not be related 🤷🏻‍♂️.

[AvihuHenya]

Thank you for your assistance.
After checking again the Connect configuration, i noticed that the group.id was missing (so both MirrorMakers take the default value). Editing this property fixed the problem.

[scholzj]

Great, glad you managed to fix it. And thanks for the update on what was the issue. Might help int he future!