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https://issues.apache.org/jira/browse/KAFKA-20898?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Chia-Ping Tsai updated KAFKA-20898:
-----------------------------------
Fix Version/s: 4.5.0
> PushTelemetry sets terminating flag on validation failure, permanently
> locking out client instance
> --------------------------------------------------------------------------------------------------
>
> Key: KAFKA-20898
> URL: https://issues.apache.org/jira/browse/KAFKA-20898
> Project: Kafka
> Issue Type: Bug
> Reporter: Ken Huang
> Assignee: Ken Huang
> Priority: Major
> Fix For: 4.5.0
>
>
> [https://github.com/apache/kafka/blob/89ccd6a1260130e1a5ea83a0aa98a7d397482ace/server/src/main/java/org/apache/kafka/server/ClientMetricsManager.java#L209]
> [https://cwiki.apache.org/confluence/spaces/KAFKA/pages/173085915/KIP-714+Client+metrics+and+observability]
> {quote}*Client termination*
> When a client with an active metrics subscription is being shut down, it
> should send its final metrics without waiting for the PushIntervalMs time.
> To avoid the receiving broker’s metrics rate-limiter discarding this
> out-of-profile push, the {{PushTelemetryRequest.Terminating}} field must be
> set to true. A broker must only allow one such unthrottled metrics push for
> each combination of client instance ID and SubscriptionId.
> In the event that the client’s metric subscription has changed and the final
> metrics push fails with error code {{UNKNOWN_SUBSCRIPTION_ID}} , the
> terminating client can choose to obtain a new subscription ID by sending a
> GetTelemetrySubscriptionsRequest and then immediately sending a
> PushTelemetryRequest with the Terminating flag set to true, or it can choose
> to abandon sending a final metrics push.{quote}
> The implementation here differs from the behavior described in the KIP. The
> second terminating request will fail.
> The flow is as follows:
> # The consumer is running normally, and the previous
> {{GetTelemetrySubscriptions}} request returns {{{}subscriptionId = X{}}}.
> # The admin runs {{{}kafka-client-metrics.sh --alter --interval 60000{}}},
> causing the broker to recalculate the subscription ID, which changes from *X*
> to {*}Y{*}.
> # The consumer begins shutting down and sends its final {{PushTelemetry}}
> request with {{terminating=true}} and the old {{{}subscriptionId = X{}}}.
> # The broker fails the subscription ID validation and returns
> {{{}UNKNOWN_SUBSCRIPTION_ID{}}}, but due to a bug, the {{terminating=true}}
> state is still recorded.
> # The consumer attempts to recover by calling {{GetTelemetrySubscriptions}}
> again, obtains the new {{{}subscriptionId = Y{}}}, and sends another
> {{PushTelemetry}} request with {{{}terminating=true{}}}.
> # The broker sees that the instance has already been marked as
> {{terminating=true}} and returns {{{}INVALID_REQUEST{}}}.
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