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https://issues.apache.org/jira/browse/KAFKA-3992?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Ewen Cheslack-Postava resolved KAFKA-3992.
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Resolution: Not A Problem
Assignee: Ewen Cheslack-Postava
As [~omkreddy] pointed out, this should only occur (both cases) if you reuse
the same client ID. The solution is to use a unique client ID for the instances
in the same process. If you do not, metrics can not be properly isolated.
In the original report, since you have an integer in the client ID and it only
happens sometimes I would guess it is due to non-thread safe client ID
generation (e.g. are you using a volatile with atomic operations, an
AtomicInteger, or locking appropriately?). In the latter case, it looks like
you are instantiating multiple instances with a fixed ID.
> InstanceAlreadyExistsException Error for Consumers Starting in Parallel
> -----------------------------------------------------------------------
>
> Key: KAFKA-3992
> URL: https://issues.apache.org/jira/browse/KAFKA-3992
> Project: Kafka
> Issue Type: Bug
> Affects Versions: 0.9.0.0
> Reporter: Alexander Cook
> Assignee: Ewen Cheslack-Postava
>
> I see the following error sometimes when I start multiple consumers at about
> the same time in the same process (separate threads). Everything seems to
> work fine afterwards, so should this not actually be an ERROR level message,
> or could there be something going wrong that I don't see?
> Let me know if I can provide any more info!
> Error processing messages: Error registering mbean
> kafka.consumer:type=consumer-node-metrics,client-id=consumer-1,node-id=node--1
> org.apache.kafka.common.KafkaException: Error registering mbean
> kafka.consumer:type=consumer-node-metrics,client-id=consumer-1,node-id=node--1
>
> Caused by: javax.management.InstanceAlreadyExistsException:
> kafka.consumer:type=consumer-node-metrics,client-id=consumer-1,node-id=node--1
> Here is the full stack trace:
> M[?:com.ibm.streamsx.messaging.kafka.KafkaConsumerV9.produceTuples:-1] -
> Error processing messages: Error registering mbean
> kafka.consumer:type=consumer-node-metrics,client-id=consumer-1,node-id=node--1
> org.apache.kafka.common.KafkaException: Error registering mbean
> kafka.consumer:type=consumer-node-metrics,client-id=consumer-1,node-id=node--1
> at
> org.apache.kafka.common.metrics.JmxReporter.reregister(JmxReporter.java:159)
> at
> org.apache.kafka.common.metrics.JmxReporter.metricChange(JmxReporter.java:77)
> at
> org.apache.kafka.common.metrics.Metrics.registerMetric(Metrics.java:288)
> at org.apache.kafka.common.metrics.Sensor.add(Sensor.java:177)
> at org.apache.kafka.common.metrics.Sensor.add(Sensor.java:162)
> at
> org.apache.kafka.common.network.Selector$SelectorMetrics.maybeRegisterConnectionMetrics(Selector.java:641)
> at org.apache.kafka.common.network.Selector.poll(Selector.java:268)
> at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:270)
> at
> org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.clientPoll(ConsumerNetworkClient.java:303)
> at
> org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:197)
> at
> org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:187)
> at
> org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.awaitMetadataUpdate(ConsumerNetworkClient.java:126)
> at
> org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureCoordinatorKnown(AbstractCoordinator.java:186)
> at
> org.apache.kafka.clients.consumer.KafkaConsumer.pollOnce(KafkaConsumer.java:857)
> at
> org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:829)
> at
> com.ibm.streamsx.messaging.kafka.KafkaConsumerV9.produceTuples(KafkaConsumerV9.java:129)
> at
> com.ibm.streamsx.messaging.kafka.KafkaConsumerV9$1.run(KafkaConsumerV9.java:70)
> at java.lang.Thread.run(Thread.java:785)
> at
> com.ibm.streams.operator.internal.runtime.OperatorThreadFactory$2.run(OperatorThreadFactory.java:137)
> Caused by: javax.management.InstanceAlreadyExistsException:
> kafka.consumer:type=consumer-node-metrics,client-id=consumer-1,node-id=node--1
> at com.sun.jmx.mbeanserver.Repository.addMBean(Repository.java:449)
> at
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerWithRepository(DefaultMBeanServerInterceptor.java:1910)
> at
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerDynamicMBean(DefaultMBeanServerInterceptor.java:978)
> at
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerObject(DefaultMBeanServerInterceptor.java:912)
> at
> com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:336)
> at
> com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:534)
> at
> org.apache.kafka.common.metrics.JmxReporter.reregister(JmxReporter.java:157)
> ... 18 more
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