I am running MirrorMaker 2 (Kafka 2.7), trying to migrate all topics from
one cluster to another while preserving through
`sync.group.offsets.enabled=true`. My source cluster is running Kafka 0.10,
while the target cluster is running 2.6.1.
While I can see data being replicated, the data on the replicated Consumer
Group in the target cluster looks wrong. The lag values of the replicated
Consumer Group are large negative values, and the LOG-END-OFFSET are mostly
0. I determined this information from kafka-consumer-groups.sh.
I checked the kafka_consumer_consumer_fetch_manager_metrics_records_lag JMX
metrics in MM2 and the reported lag is zero for all partitions.
By using `sync.group.offsets.enabled=true`, I envisioned that MM2 will
automatically replicate and sync all Consumer Groups with a meaningful
offset in the target cluster. Am I misunderstanding how MM2 is supposed to
work?
Here is my mm2.properties and the CG details.
# mm2.properties
```
clusters = src, dst
src.bootstrap.servers = 10.0.0.1:9092
dst.bootstrap.servers = 10.0.0.2:9092
src->dst.enabled = true
src->dst.topics = compute.*
src->dst.offset.flush.timeout.ms=60000
src->dst.buffer.memory=10000
dst->src.enabled = true
dst->src.topics = .*
replication.factor=3
src->dst.sync.group.offsets.enabled = true
src->dst.emit.checkpoints.enabled = true
src->dst.consumer.auto.offset.reset=latest
consumer.auto.offset.reset = latest
auto.offset.reset = latest
replication.policy.class =
com.amazonaws.kafka.samples.CustomMM2ReplicationPolicy
checkpoints.topic.replication.factor=3
heartbeats.topic.replication.factor=3
offset-syncs.topic.replication.factor=3
offset.storage.replication.factor=3
status.storage.replication.factor=3
config.storage.replication.factor=3
sync.topic.acls.enabled = false
sync.group.offsets.enabled = true
emit.checkpoints.enabled = true
tasks.max = 8
dst.producer.offset.flush.timeout.ms = 60000
dst.offset.flush.timeout.ms = 60000
```
Consumer Group details
```
GROUP TOPIC
PARTITION CURRENT-OFFSET LOG-END-OFFSET LAG
CONSUMER-ID HOST CLIENT-ID
kafka-group-Compute-Requests Compute-Requests 57 5305947 0
-5305947 - - -
kafka-group-Compute-Requests Compute-Requests 20 5164205 0
-5164205 - - -
kafka-group-Compute-Requests Compute-Requests 53 4208527 0
-4208527 - - -
kafka-group-Compute-Requests Compute-Requests 82 5247928 0
-5247928 - - -
kafka-group-Compute-Requests Compute-Requests 65 5574520 0
-5574520 - - -
kafka-group-Compute-Requests Compute-Requests 11 5190708
209 -5190499 - - -
```
Thanks
... Alan
