Several user-level KeeperExceptions when following the Confluent Platform 3.0.1 Quickstart

[Denis Kalinin]

Hi!

I'm following the quickstart tutorial for Confluent Platform 3.0.1 (I'm on Ubuntu and use a standalone install from a zip file if that matters). It works fine, but every time Kafka connects to Zookeeper I see the following in Zookeeper's logs:

[2016-10-08 18:52:23,727] INFO Got user-level KeeperException when processing sessionid:0x157a4fe62af0000 type:delete cxid:0x32 zxid:0x82 txntype:-1 reqpath:n/a Error Path:/admin/preferred_replica_election Error:KeeperErrorCode = NoNode for /admin/preferred_replica_election (org.apache.zookeeper.server.PrepRequestProcessor)

[2016-10-08 18:52:23,843] INFO Got user-level KeeperException when processing sessionid:0x157a4fe62af0000 type:create cxid:0x39 zxid:0x83 txntype:-1 reqpath:n/a Error Path:/brokers Error:KeeperErrorCode = NodeExists for /brokers (org.apache.zookeeper.server.PrepRequestProcessor)

[2016-10-08 18:52:23,845] INFO Got user-level KeeperException when processing sessionid:0x157a4fe62af0000 type:create cxid:0x3a zxid:0x84 txntype:-1 reqpath:n/a Error Path:/brokers/ids Error:KeeperErrorCode = NodeExists for /brokers/ids (org.apache.zookeeper.server.PrepRequestProcessor) 

I haven't changed anything in the config files, and apparently, these errors don't prevent Kafka from receiving messages, so the rest of the tutorial works fine. 

But still, what could be the source of these errors?

I tried restarting everything and clearing zookeeper and kafka stuff from /tmp, but it doesn't help.

[Gwen Shapira]

Those are not errors, you can see the log level is INFO. It is simply
logging that Kafka tried to create a node that already exists. Totally
normal behavior for Kafka and nothing to worry about.

Gwen

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[Denis Kalinin]

Ahh, it's good to know these are not real errors.

On a related note, I think I found some discrepancy in the tutorial. For version 3.0.1, it says (about starting Zookeper and Kafka):

You will need write access to /var/lib for this step and the next

In reality, though, both Zookeper and Kafka are configured to put their stuff in /tmp, not /var/lib.

Thanks!

[Gwen Shapira]

Thanks for the feedback. This really depends on which packaging you are using :)

Apache Kafka uses /tmp by default because we assume it will be used by
developers, testing environments and production. We want it to run
with no issues out of the box for everyone and /tmp fits the bill.

Confluent's distribution, which includes Apache Kafka, is configured
more toward production systems (especially the deb/rpm/docker
packaging). So we are using /var/lib and /var/log for storage.
Unfortunately, this caused some people to run into unexpected issues
with the quickstart, so we decided to call it out.

Apologies if you found it confusing. It is difficult (especially for
engineers) to make tutorials that work for everyone...

Gwen

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[Anum Zargar]

Hi All need your help :-
how to fetch data from consumer

i have installed

kafka on one server

and php ,libradkafka and rdkafka on other server.


this is my code of php server

<?php
$rk = new RdKafka\Producer();
$rk->setLogLevel(LOG_DEBUG);
$rk->addBrokers("206.191.151.208");
// $rk->addBrokers("127.0.0.1");

$topic = $rk->newTopic("too");
$arr = array("name"=>"too","age"=>20);
$input = json_encode($arr,true);
$topic->produce(RD_KAFKA_PARTITION_UA, 0, $input);
//r ($i = 0; $i < 10; $i++) {
// $topic->produce(RD_KAFKA_PARTITION_UA, 0, "Mob $i");
//}
?>

how will fetch the output from server kafka using consumer

this is simple

just started