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https://issues.apache.org/jira/browse/KAFKA-10429?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17187992#comment-17187992
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John Roesler commented on KAFKA-10429:
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Hi Navinder,
My first thought is that version 1.1.1 is extremely old, and a lot has actually
changed in the consumers since then. Is there any chance you can try with a
newer version of Streams and see if you still observe the issue?
Aside from that, from the logs you posted, it looks like in only took that
instance a few seconds to re-acquire the connection to the coordinator, but the
next paragraph implies that disconnections have lasted hours. Can you clarify?
A few other notes:
* Disconnecting from the coordinator shouldn't interrupt processing, since you
can still fetch from the leader and followers of the topic partitions you're
assigned
* If an instance is disconnected for longer than the session interval, you
would actually see rebalances caused by that interval having dropped out of the
group
* If the log cleaner removes some offsets after the consumer's current
position, there would be an InvalidOffsetException (unless there's an
auto-reset policy configured), so you wouldn't silently miss data
> Group Coordinator unavailability leads to missing events
> --------------------------------------------------------
>
> Key: KAFKA-10429
> URL: https://issues.apache.org/jira/browse/KAFKA-10429
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 1.1.1
> Reporter: Navinder Brar
> Priority: Major
>
> We are regularly getting this Exception in logs.
> [2020-08-25 03:24:59,214] INFO [Consumer
> clientId=appId-StreamThread-1-consumer, groupId=dashavatara] Group
> coordinator ip:9092 (id: 1452096777 rack: null) is *unavailable* or invalid,
> will attempt rediscovery
> (org.apache.kafka.clients.consumer.internals.AbstractCoordinator)
>
> And after sometime it becomes discoverable:
> [2020-08-25 03:25:02,218] INFO [Consumer
> clientId=appId-c3d1d186-e487-4993-ae3d-5fed75887e6b-StreamThread-1-consumer,
> groupId=appId] Discovered group coordinator ip:9092 (id: 1452096777 rack:
> null) (org.apache.kafka.clients.consumer.internals.AbstractCoordinator)
>
> Now, the doubt I have is why this unavailability doesn't trigger a rebalance
> in the cluster. We have few hours of retention on the source Kafka Topics and
> sometimes this unavailability stays over for more than few hours and since it
> doesn't trigger a rebalance or stops processing on other nodes(which are
> connected to GC) we never come to know that some issue has happened and till
> then we lose events from our source topics.
>
> There are some resolutions mentioned on stackoverflow but those configs are
> already set in our kafka:
> default.replication.factor=3
> offsets.topic.replication.factor=3
>
> It would be great to understand why this issue is happening and why it
> doesn't trigger a rebalance and is there any known solution for it.
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