[
https://issues.apache.org/jira/browse/FLINK-9630?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16559076#comment-16559076
]
ASF GitHub Bot commented on FLINK-9630:
---------------------------------------
ubyyj commented on issue #6336: [FLINK-9630] [connector]
Kafka09PartitionDiscoverer cause connection …
URL: https://github.com/apache/flink/pull/6336#issuecomment-408274936
@tillrohrmann @zentol would you please take a look, and if everything looks
good to you, can you please get this merged? Thanks
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
> Kafka09PartitionDiscoverer cause connection leak on
> TopicAuthorizationException
> -------------------------------------------------------------------------------
>
> Key: FLINK-9630
> URL: https://issues.apache.org/jira/browse/FLINK-9630
> Project: Flink
> Issue Type: Bug
> Components: Kafka Connector
> Affects Versions: 1.5.0, 1.4.2
> Environment: Linux 2.6, java 8, Kafka broker 0.10.x
> Reporter: Youjun Yuan
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.5.3
>
>
> when the Kafka topic got deleted, during task starting process,
> Kafka09PartitionDiscoverer will get a *TopicAuthorizationException* in
> getAllPartitionsForTopics(), and it get no chance to close the
> kafkaConsumer, hence resulting TCP connection leak (to Kafka broker).
>
> *this issue can bring down the whole Flink cluster*, because, in a default
> setup (fixedDelay with INT.MAX restart attempt), job manager will randomly
> schedule the job to any TaskManager that has free slot, and each attemp will
> cause the TaskManager to leak a TCP connection, eventually almost every
> TaskManager will run out of file handle, hence no taskmanger could make
> snapshot, or accept new job. Effectly stops the whole cluster.
>
> The leak happens when StreamTask.invoke() calls openAllOperators(), then
> FlinkKafkaConsumerBase.open() calls partitionDiscoverer.discoverPartitions(),
> when kafkaConsumer.partitionsFor(topic) in
> KafkaPartitionDiscoverer.getAllPartitionsForTopics() hit a
> *TopicAuthorizationException,* no one catches this.
> Though StreamTask.open catches Exception and invoks the dispose() method of
> each operator, which eventaully invoke FlinkKakfaConsumerBase.cancel(),
> however it does not close the kakfaConsumer in partitionDiscoverer, not even
> invoke the partitionDiscoverer.wakeup(), because the discoveryLoopThread was
> null.
>
> below is the code of FlinkKakfaConsumerBase.cancel() for your convenience
> public void cancel() {
> // set ourselves as not running;
> // this would let the main discovery loop escape as soon as possible
> running = false;
> if (discoveryLoopThread != null) {
> if (partitionDiscoverer != null)
> { // we cannot close the discoverer here, as it is error-prone to
> concurrent access; // only wakeup the discoverer, the discovery
> loop will clean itself up after it escapes
> partitionDiscoverer.wakeup(); }
> // the discovery loop may currently be sleeping in-between
> // consecutive discoveries; interrupt to shutdown faster
> discoveryLoopThread.interrupt();
> }
> // abort the fetcher, if there is one
> if (kafkaFetcher != null)
> { kafkaFetcher.cancel(); }
> }
>
>
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
