Thank you, everyone for all your assistance, my project is successfully integrated with Kafka.While testing i came with a issue for which i need a little assistance. my producer and consumer both were pointing to Kafka broker say KB-1. i have cluster of brokers with replication factor 1.KB-1 dies due to some internal reason so we switched the IP's of our producer and consumer to another broker of same cluster KB-2. It was effective to consume all data and process the necessary alerts necessary,but when i tried to produce the data through producer with KB-2 IP in bootstrap server it failed to produce giving the following error: org.apache.kafka.common.errors.TimeoutException
please also explain single point failure if possible.
thank you for the help.
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I have a multi-node Kafka cluster which I use for consuming and producing.
In my application, I use confluent-kafka-go(1.6.1) to create producers and consumers. Everything works great when I produce and consume messages.
This is how I configure my bootstrap server list
"bootstrap.servers":"localhost:9092,localhost:9093,localhost:9094"
But the moment when I start giving out the IP address of the brokers in bootstrap.servers and if the first broker is down, it seems that the producer repeatedly fails creation telling
Failed to initialize Producer ID: Local: Timed out
If I remove the IP of the failed node, producing and consuming messages work.
If the broker is down after I create the producer/consumer, they continue to be usable by switching over to other nodes.
How should I configure bootstrap.servers in such a way that the producer will be created using the available nodes?
You shouldn't really be running 3 brokers on the same machine anyway, but using multiple unique servers works fine for me when the first is down (and the cluster elects a different leader if it needs to), so sounds like you either lost the primary leader of your topic partitions or you've lost the Controller. Enabling retires on the producer should be able fix itself (by making a new metadata request for partition leaders)
Overall, it's just a CSV; there's no other way to configure that property itself. You could stick a reverse proxy in front of the brokers that resolves only to healthy nodes, but then you'd be conflicting with a potential DNS cache
We have deployed multiple Kafka consumers in container's clusters. All are working properly except for one, which is throwing warning "Connection to node 0 could not be established. Broker may not be available", however, this error appears only in one of the containers, and this consumer is running in the same network and server of the others. So I have ruled out issues with kafka server configuration.
I tried changing the groupid of the consumer and I got it working for some minutes, but now warn is appearing again. I consume all topics used by this consumer from a bash shell and I can consume.
Having into account the above context, I think it could be due to bad practice in the consumer software code, also, it could be about offsets got damaged. How could I identify if are there some of this kind using kafka logs?
You can exec into the container and netcat the broker's advertised addresses to verify connectivity.
You can also use the Kafka shell scripts to verify consuming functionality, as always.
Corrupted offsets would prevent any consumer from reading, not only one. Bad code practices wouldn't show up in logs
If you have the container running "on same server as others", I'd suggest working with affinity rules and constraints to spread your applications onto multiple servers before placing on the same machine
I need to configure a Kafka cluster on different machines but it does not work, when I start producer and consumer the following errors are displayed:
Producer Error Output
Consumer Error Output
Can you help me please.
In order to get started, I would recommend to read https://kafka.apache.org/documentation/#quickstart. BTW, in your case; you haven't started Kafka yet.
You should start services in following order:
zookeeper
Kafka
producer
consumer
I have two kafka clusters. One is two broker node kafka cluster with replication factor 2 and second one is single broker kafka cluster.
Sometimes observed below exception in Kafka controller.log. What would be the possible reason? Please help me
java.nio.channels.ClosedSelectorException
at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:83)
at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
at org.apache.kafka.common.network.Selector.select(Selector.java:489)
at org.apache.kafka.common.network.Selector.poll(Selector.java:298)
at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:349)
at kafka.utils.NetworkClientBlockingOps$.recursivePoll$1(NetworkClientBlockingOps.scala:135)
at kafka.utils.NetworkClientBlockingOps$.pollContinuously$extension(NetworkClientBlockingOps.scala:142)
at kafka.utils.NetworkClientBlockingOps$.blockingSendAndReceive$extension(NetworkClientBlockingOps.scala:108)
at kafka.controller.RequestSendThread.liftedTree1$1(ControllerChannelManager.scala:192)
at kafka.controller.RequestSendThread.doWork(ControllerChannelManager.scala:184)
at kafka.utils.ShutdownableThread.run(ShutdownableThread.scala:63)
I observed that problem when there is a connection problem. Main reason could be the zookeeper connection. Did you try to enable debug in kafka broker and read the logs? Because, you need to see detailed logs from server.
We're testing out the Producer and Consumer using Kafka. A few questions:
What happens when all the brokers are down and they're not responding at all?
Does the Producer need to keep pinging the Kafka brokers to know when it is back up online? Or is there a more elegant way for the Producer application to know?
How does Zookeeper help in all this? What if the ZK is down as well?
If one or more brokers are down, the producer will re-try for a certain period of time (based on the settings). And during this time one or more of the consumers will not be able to read anything until the respective brokers are up.
But if the cluster is down for a longer period than your total re-try period, then probably you need to find a way to resend those failed messages again.
This is the one scenario where Kafka Mirroring(MirrorMaker tool) comes into picture.
https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=27846330
Producer will fail because cluster will be unavailable, this means they will get a non retriable error from kafka client implementation and depending on your client process, message will buffer on the local send queue of your application.
I'm sure that if zookeeper is down your system will not work anymore. This is one of the weakness of Kafka, he need zookeeper to work.