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Calvin Liu commented on KAFKA-15353: ------------------------------------ [~mimaison] >From my understanding # It only happens in Kraft mode. # The issue can happen during the roll where the broker has to downgrade the AlterPartition requests. # If the leader needs to resend the AlterPartition request, the new request will have an empty ISR. # The controller does not update the ISR field because it avoids persisting an empty ISR. However, the partition will become leaderless and offline. The problem can be resolved if any ISR broker gets fenced/rebooted. > Empty ISR returned from controller after AlterPartition request > --------------------------------------------------------------- > > Key: KAFKA-15353 > URL: https://issues.apache.org/jira/browse/KAFKA-15353 > Project: Kafka > Issue Type: Bug > Components: core > Affects Versions: 3.5.0 > Reporter: Luke Chen > Assignee: Calvin Liu > Priority: Blocker > Fix For: 3.6.0, 3.5.2 > > > In > [KIP-903|https://cwiki.apache.org/confluence/display/KAFKA/KIP-903%3A+Replicas+with+stale+broker+epoch+should+not+be+allowed+to+join+the+ISR], > (more specifically this [PR|https://github.com/apache/kafka/pull/13408]), we > bumped the AlterPartitionRequest version to 3 to use `NewIsrWithEpochs` field > instead of `NewIsr` one. And when building the request for older version, > we'll manually convert/downgrade the request into the older version for > backward compatibility > [here|https://github.com/apache/kafka/blob/6bd17419b76f8cf8d7e4a11c071494dfaa72cd50/clients/src/main/java/org/apache/kafka/common/requests/AlterPartitionRequest.java#L85-L96], > to extract ISR info from `NewIsrWithEpochs` and then fill in the `NewIsr` > field, and then clear the `NewIsrWithEpochs` field. > > The problem is, when the AlterPartitionRequest sent out for the first time, > if there's some transient error (ex: NOT_CONTROLLER), we'll retry. On the > retry, we'll build the AlterPartitionRequest again. But this time, the > request data is the one that already converted above. At this point, when we > try to extract the ISR from `NewIsrWithEpochs`, we'll get empty. So, we'll > send out an AlterPartition request with empty ISR, and impacting the kafka > availability. > > From the log, I can see this: > {code:java} > [2023-08-16 03:57:55,122] INFO [Partition test_topic-1 broker=3] ISR updated > to (under-min-isr) and version updated to 9 (kafka.cluster.Partition) > ... > [2023-08-16 03:57:55,157] ERROR [ReplicaManager broker=3] Error processing > append operation on partition test_topic-1 > (kafka.server.ReplicaManager)org.apache.kafka.common.errors.NotEnoughReplicasException: > The size of the current ISR Set() is insufficient to satisfy the min.isr > requirement of 2 for partition test_topic-1 {code} > > h4. *Impact:* > This will happen when users trying to upgrade from versions < 3.5.0 to 3.5.0 > or later. During the rolling upgrade, there will be some nodes in v3.5.0, and > some are not. So, for the node in v3.5.0 will try to build an old version of > AlterPartitionRequest. And then, if it happen to have some transient error > during the AlterPartitionRequest send, the ISR will be empty and no producers > will be able to write data to the partitions. -- This message was sent by Atlassian Jira (v8.20.10#820010)