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https://issues.apache.org/jira/browse/KAFKA-19785?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18081786#comment-18081786
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Kevin Wu commented on KAFKA-19785:
----------------------------------
Hi [~jwaibel2],
{noformat}
2026-05-02 00:56:00 WARN [main] QuorumState:158 - [RaftManager id=1] Epoch from
quorum store file
(/var/lib/kafka/data-0/kafka-log1/__cluster_metadata-0/quorum-state) is 0,
which is smaller than last written epoch 66 in the log{noformat}
>From my reading of the code, the epoch being 0 means that this file does not
>exist when the pod is restarted. Take a look at `QuorumState#L135`. Are you
>able to confirm that this file does not exist at the time of restart? If so,
>that could be an operator misconfiguration. We should add a log message to
>Kafka for this case. It's interesting to me that it seems the `quorum-state`
>file is lost, but not the log itself.
Raft assumes persistent data like the information in `quorum-state` cannot be
permanently lost for a voter. For example, losing this data can violate the
1-vote per epoch invariant, resulting in two leaders for the same epoch. If
this persistent data is lost, your second incarnation of the pod is a new
logical voter from the perspective of KRaft.
Have you considered using
[https://cwiki.apache.org/confluence/display/KAFKA/KIP-853%3A+KRaft+Controller+Membership+Changes]
or configuring your orchestration layer to use the same persistent volume when
the kafka pod is restarted?
> Two Kafka brokers were not active in 3 node cluster setup
> ---------------------------------------------------------
>
> Key: KAFKA-19785
> URL: https://issues.apache.org/jira/browse/KAFKA-19785
> Project: Kafka
> Issue Type: Bug
> Components: core, kraft
> Affects Versions: 4.0.0
> Reporter: Sravani
> Priority: Major
> Labels: kraft
>
> Hi Team,
> We were facing kafka issue where two of the kafka brokers were fenced and
> Kafka was not able to process messages. We are using Kafka 4.0.0 version.
> Below are the errors.
>
> Sep 22 09:41:42 host kafka[42245]: [2025-09-22 07:41:42,419] ERROR
> Encountered fatal fault: Unexpected error in raft IO thread
> (org.apache.kafka.server.fault.ProcessTerminatingFaultHandler)
> Sep 22 09:41:42 host kafka[42245]: java.lang.IllegalStateException: Received
> request or response with leader OptionalInt[3] and epoch 55 which is
> inconsistent with current leader OptionalInt.empty and epoch 55
> Sep 22 09:41:42 host kafka[42245]: #011at
> org.apache.kafka.raft.KafkaRaftClient.maybeTransition(KafkaRaftClient.java:2528)
> ~[kafka-raft-4.0.0.jar:?]
> Sep 22 09:41:42 host kafka[42245]: #011at
> org.apache.kafka.raft.KafkaRaftClient.maybeHandleCommonResponse(KafkaRaftClient.java:2484)
> ~[kafka-raft-4.0.0.jar:?]
> Sep 22 09:41:42 host kafka[42245]: #011at
> org.apache.kafka.raft.KafkaRaftClient.handleFetchResponse(KafkaRaftClient.java:1707)
> ~[kafka-raft-4.0.0.jar:?]
> Sep 22 09:41:42 host kafka[42245]: #011at
> org.apache.kafka.raft.KafkaRaftClient.handleResponse(KafkaRaftClient.java:2568)
> ~[kafka-raft-4.0.0.jar:?]
> Sep 22 09:41:42 host kafka[42245]: #011at
> org.apache.kafka.raft.KafkaRaftClient.handleInboundMessage(KafkaRaftClient.java:2724)
> ~[kafka-raft-4.0.0.jar:?]
> Sep 22 09:41:42 host kafka[42245]: #011at
> org.apache.kafka.raft.KafkaRaftClient.poll(KafkaRaftClient.java:3460)
> ~[kafka-raft-4.0.0.jar:?]
> Sep 22 09:41:42 host kafka[42245]: #011at
> org.apache.kafka.raft.KafkaRaftClientDriver.doWork(KafkaRaftClientDriver.java:64)
> [kafka-raft-4.0.0.jar:?]
> Sep 22 09:41:42 host kafka[42245]: #011at
> org.apache.kafka.server.util.ShutdownableThread.run(ShutdownableThread.java:136)
> [kafka-server-common-4.0.0.jar:?]
> Below metrics shows Fenceborker count as 2.0
> kafka_controller_KafkaController_Value\{name="ActiveBrokerCount",} 1.0
> kafka_controller_KafkaController_Value\{name="GlobalTopicCount",} 23.0
> kafka_controller_KafkaController_Value\{name="FencedBrokerCount",} 2.0
> Please help us to resolve this issue.
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