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https://issues.apache.org/jira/browse/KAFKA-6669?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16401859#comment-16401859
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Sergey Korytnikov commented on KAFKA-6669:
------------------------------------------
*Usa-case example:*
Kafka cluster is running in OpenShift as a distributed setup of 5 brokers. Each
broker's pod service port is exposed as a separate port on localhost interface.
KafkaProducer connects to cluster from outside of OpenShift environment and
specifies bootstrap servers as:
|{{bootstrap.servers=localhost:}}{{9092}}{{,localhost:}}{{9093}}{{,localhost:}}{{9094}}{{,localhost:}}{{9095}}{{,localhost:}}{{9096}}|
When message is getting sent, Kafka client recieves clusters metadata with pods
internal DNS names and delivery is failed:
|{{DEBUG org.apache.kafka.clients.NetworkClient[kafka-producer-network-thread
\| producer-}}{{1}}{{] - [Producer clientId=producer-}}{{1}}{{] Initiating
connection to node kafka-}}{{2}}{{.kafka.myproject.svc.cluster.local:}}{{9092}}
{{(id: }}{{1003}} {{rack: }}{{null}}{{)}}
{{DEBUG org.apache.kafka.clients.NetworkClient[kafka-producer-network-thread \|
producer-}}{{1}}{{] - [Producer clientId=producer-}}{{1}}{{] Error connecting
to node kafka-}}{{2}}{{.kafka.myproject.svc.cluster.local:}}{{9092}} {{(id:
}}{{1003}} {{rack: }}{{null}}{{)}}
{{java.io.IOException: Can't resolve address:
kafka-}}{{2}}{{.kafka.myproject.svc.cluster.local:}}{{9092}}
{{ }}{{at
org.apache.kafka.common.network.Selector.doConnect(Selector.java:}}{{258}}{{)}}
{{ }}{{at
org.apache.kafka.common.network.Selector.connect(Selector.java:}}{{237}}{{)}}
{{ }}{{at
org.apache.kafka.clients.NetworkClient.initiateConnect(NetworkClient.java:}}{{792}}{{)}}
{{ }}{{at
org.apache.kafka.clients.NetworkClient.ready(NetworkClient.java:}}{{230}}{{)}}
{{ }}{{at
org.apache.kafka.clients.producer.internals.Sender.sendProducerData(Sender.java:}}{{263}}{{)}}
{{ }}{{at
org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:}}{{238}}{{)}}
{{ }}{{at
org.apache.kafka.clients.producer.internals.Sender.run(Sender.java:}}{{163}}{{)}}
{{ }}{{at java.base/java.lang.Thread.run(Thread.java:}}{{844}}{{)}}
{{Caused by: java.nio.channels.UnresolvedAddressException}}
{{ }}{{at java.base/sun.nio.ch.Net.checkAddress(Net.java:}}{{112}}{{)}}
{{ }}{{at
java.base/sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:}}{{622}}{{)}}
{{ }}{{at
org.apache.kafka.common.network.Selector.doConnect(Selector.java:}}{{256}}{{)}}
{{ }}{{... }}{{7}} {{more}}|
> KIP-271: Add NetworkClient redirector
> -------------------------------------
>
> Key: KAFKA-6669
> URL: https://issues.apache.org/jira/browse/KAFKA-6669
> Project: Kafka
> Issue Type: Improvement
> Components: clients
> Reporter: Sergey Korytnikov
> Priority: Major
>
> "KIP-271 Add NetworkClient redirector" purposes the change to accommodate
> environments without proper DNS support, when KafkaProducer or KafkaConsumer
> tries to connect to Kafka brokers that are inside another network.
> Currently, Kafka client connection fails with
> "[java.io|http://java.io/].IOException: Can't resolve address" after Kafka
> cluster metadata is updated with internal DNS names of brokers, unreachable
> by Client. The example of such configuration might be a Java Client calling
> Kafka Cluster from outside of Kubernetes cluster or AWS network.
> The KIP improves NetworkClient to redirect the call to alternative network
> address and provides developers with additional Configurable interface to
> specify redirection rules.
>
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