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From "Bateman, Matt" <mabate...@ebay.com>
Subject RE: Only one broker has partitions
Date Fri, 17 Feb 2012 19:05:36 GMT
We're using a single topic ("test-topic") in our QA setup. Originally we were using only one
broker (id 0) in or testing environment. Recently we added two more (id 2 and 3) for a total
of 3 in our cluster. ZooKeeper shows that the topic and partitions are registered by broker
0 as expected. They do not show for brokers 2 and 3. I'm guessing that if a broker is not
registered with ZooKeeper when a producer sends the first message for a topic, it will never
process messages for that topic?

As a test, I sent messages into the cluster for a new topic. The producer logs show

[2012-02-17 10:31:12,698] DEBUG Getting the number of broker partitions registered for topic:
cluster-test (kafka.producer.Producer)
[2012-02-17 10:31:12,698] DEBUG Currently, no brokers are registered under topic: cluster-test
(kafka.producer.ZKBrokerPartitionInfo)
[2012-02-17 10:31:12,698] DEBUG Bootstrapping topic: cluster-test with available brokers in
the cluster with default number of partitions = 1 (kafka.producer.ZKBrokerPartitionInfo)
[2012-02-17 10:31:12,705] DEBUG Adding following broker id, partition id for NEW topic: cluster-test=TreeSet(0-0,
2-0, 3-0) (kafka.producer.ZKBrokerPartitionInfo)
[2012-02-17 10:31:12,705] DEBUG Broker partitions registered for topic: cluster-test = List(0-0,
2-0, 3-0) (kafka.producer.Producer)

This seems logical, all brokers are mentioned. Then I see the following (each broker is configured
to use 20 partitions):

[2012-02-17 10:31:12,840] DEBUG Sending message to broker 2 (kafka.producer.ProducerPool)
[2012-02-17 10:31:12,953] DEBUG [BrokerTopicsListener] List of topics changed at /brokers/topics
Updated topics -> [topic1, topic2, cluster-test, topic3, test-topic, topic4] (kafka.producer.ZKBrokerPartitionInfo$BrokerTopicsListener)
[2012-02-17 10:31:12,953] DEBUG [BrokerTopicsListener] Old list of topics: Set(topic1, topic3,
topic2, test-topic, topic4) (kafka.producer.ZKBrokerPartitionInfo$BrokerTopicsListener)
[2012-02-17 10:31:12,963] DEBUG [BrokerTopicsListener] Updated list of topics: Set(topic4,
test-topic, topic2, topic3, cluster-test, topic1) (kafka.producer.ZKBrokerPartitionInfo$BrokerTopicsListener)
[2012-02-17 10:31:12,963] DEBUG [BrokerTopicsListener] List of newly registered topics: Set(cluster-test)
(kafka.producer.ZKBrokerPartitionInfo$BrokerTopicsListener)
[2012-02-17 10:31:12,978] DEBUG [BrokerTopicsListener] Currently registered list of brokers
for topic: cluster-test are Buffer(2) (kafka.producer.ZKBrokerPartitionInfo$BrokerTopicsListener)
[2012-02-17 10:31:12,978] DEBUG [BrokerTopicsListener] Unregistered list of brokers for topic:
cluster-test are TreeSet(0-0, 2-0, 3-0) (kafka.producer.ZKBrokerPartitionInfo$BrokerTopicsListener)
[2012-02-17 10:31:12,980] DEBUG [BrokerTopicsListener] List of broker partitions for topic:
cluster-test are TreeSet(0-0, 2-0, 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, 2-8, 2-9, 2-10, 2-11,
2-12, 2-13, 2-14, 2-15, 2-16, 2-17, 2-18, 2-19, 3-0) (kafka.producer.ZKBrokerPartitionInfo$BrokerTopicsListener)
[2012-02-17 10:31:13,841] DEBUG Getting the number of broker partitions registered for topic:
cluster-test (kafka.producer.Producer)
[2012-02-17 10:31:13,841] DEBUG Broker partitions registered for topic: cluster-test = List(0-0,
2-0, 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, 2-8, 2-9, 2-10, 2-11, 2-12, 2-13, 2-14, 2-15, 2-16,
2-17, 2-18, 2-19, 3-0) (kafka.producer.Producer)

This seems strange, shouldn't each broker host each partition for the new "cluster-topic"?

I then see the producer debug messages showing messages sent to broker 2.

What am I missing here?

Thanks,

Matt

-----Original Message-----
From: Jun Rao [mailto:junrao@gmail.com] 
Sent: Thursday, February 16, 2012 6:08 PM
To: kafka-users@incubator.apache.org
Subject: Re: Only one broker has partitions

Try enabling debug level logging in Producer class. It will show which broker the partitioner
selects.

Thanks,

Jun

On Thu, Feb 16, 2012 at 2:48 PM, Bateman, Matt <mabateman@ebay.com> wrote:

> Hi All,
>
> I feel like this was discussed at some point but couldn't find it in 
> the docs or the mailing list archives, hopefully this isn't redundant.
>
> We are running 3 version 0.7 brokers using an ensemble of 3 ZooKeeper 
> nodes. We use a ZooKeeper connect string in the producers and consumers.
> ZooKeeper is enabled on each broker. We use the default partitioner in 
> the producer supplying it an integer. Each broker has a unique Id.
>
> However, only one broker has any log files. The log from that machine 
> shows it registering the topics in ZooKeeper. The other brokers don't 
> have any log files.
>
> Have a I missed a basic configuration setting or misunderstood 
> something operational? The only slight mismatch I see is we run 
> ZooKeeper 3.3.4 but it seems like 3.3.3 is being used by 0.7.
>
> Thanks,
>
> Matt
>

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