Cliente consumidor Apache Kafka conectando-se ao Apache Zookeeper: EndOfStreamException

Question

Eu recebo um erro ao tentar 'consumir' mensagens do Kafka (2.9.2-0.8.1) com um Zookeer independente (3.4.5). Você pode ver o código-fonte abaixo, bem como a mensagem de erro e o arquivo de log do Zookeeper.

Eu não tenho certeza se as bibliotecas Java são incompatíveis, porque eu adicionei a dependência kafka_0.9.2 (0.8.1) via Maven que automaticamente resolveu a dependência de zkclient (0.3) e zookeeper (3.3.4).

O código-fonte do consumidor:

import java.util.Properties;

import kafka.consumer.Consumer;
import kafka.consumer.ConsumerConfig;
import kafka.javaapi.consumer.ConsumerConnector;

public class ConsumerTest {

    public static void main(String[] args) 
    {
        try
        {
            Properties props = new Properties();

            props.put("zookeeper.connect", "192.168.0.1:2181/kafka");
            props.put("group.id", "my-consumer");
            props.put("zookeeper.session.timeout.ms", "400");
            props.put("zookeeper.sync.time.ms", "200");
            props.put("auto.commit.interval.ms", "1000");

            ConsumerConfig config = new ConsumerConfig(props);
            @SuppressWarnings("unused")
            ConsumerConnector consumer = Consumer.createJavaConsumerConnector(config);
        }
        catch(Exception e)
        {
            System.out.println(e.getMessage());
            e.printStackTrace();
        }
    }
}

O pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>test.my</groupId>
  <artifactId>kafka-consumer</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <dependencies>
    <dependency>
        <groupId>org.apache.kafka</groupId>
        <artifactId>kafka_2.9.2</artifactId>
        <exclusions>
            <exclusion>
                <artifactId>jms</artifactId>
                <groupId>javax.jms</groupId>
            </exclusion>
            <exclusion>
                <artifactId>jmxtools</artifactId>
                <groupId>com.sun.jdmk</groupId>
            </exclusion>
            <exclusion>
                <artifactId>jmxri</artifactId>
                <groupId>com.sun.jmx</groupId>
            </exclusion>
        </exclusions>
    </dependency>
  </dependencies>
  <dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.apache.kafka</groupId>
            <artifactId>kafka_2.9.2</artifactId>
            <version>0.8.1</version>
        </dependency>
    </dependencies>
  </dependencyManagement>
</project>

A mensagem de exceção e o rastreamento de pilha:

Unable to connect to zookeeper server within timeout: 400
org.I0Itec.zkclient.exception.ZkTimeoutException: Unable to connect to zookeeper server within timeout: 400
    at org.I0Itec.zkclient.ZkClient.connect(ZkClient.java:880)
    at org.I0Itec.zkclient.ZkClient.<init>(ZkClient.java:98)
    at org.I0Itec.zkclient.ZkClient.<init>(ZkClient.java:84)
    at kafka.consumer.ZookeeperConsumerConnector.connectZk(ZookeeperConsumerConnector.scala:156)
    at kafka.consumer.ZookeeperConsumerConnector.<init>(ZookeeperConsumerConnector.scala:114)
    at kafka.javaapi.consumer.ZookeeperConsumerConnector.<init>(ZookeeperConsumerConnector.scala:65)
    at kafka.javaapi.consumer.ZookeeperConsumerConnector.<init>(ZookeeperConsumerConnector.scala:67)
    at kafka.consumer.Consumer$.createJavaConsumerConnector(ConsumerConnector.scala:100)
    at kafka.consumer.Consumer.createJavaConsumerConnector(ConsumerConnector.scala)
    at ConsumerTest.main(ConsumerTest.java:23)

O log do zookeeper:

2014-05-06 11:48:11,907 [myid:] - INFO  [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOServerCnxnFactory@197] - Accepted socket connection from /192.168.0.4:52568
2014-05-06 11:48:11,909 [myid:] - WARN  [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOServerCnxn@349] - caught end of stream exception
EndOfStreamException: Unable to read additional data from client sessionid 0x0, likely client has closed socket
         at org.apache.zookeeper.server.NIOServerCnxn.doIO(NIOServerCnxn.java:220)
         at org.apache.zookeeper.server.NIOServerCnxnFactory.run(NIOServerCnxnFactory.java:208)
         at java.lang.Thread.run(Thread.java:701)
2014-05-06 11:48:11,909 [myid:] - INFO  [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:2181:NIOServerCnxn@1001] - Closed socket connection for client /192.168.0.4:52568 (no session established for client)

Note que posso produzir e consumir mensagens dos nós do Kafka com as ferramentas de linha de comando:

$ sudo -u kafka bin/kafka-console-producer.sh --broker-list 192.168.0.2:9092,192.168.0.3:9092 --topic my-topic
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
This is a first message.
This is a second message.
$ sudo -u kafka bin/kafka-console-consumer.sh --zookeeper 192.168.0.1:2181/kafka --topic my-topic --from-beginning
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
This is a first message.
This is a second message.

Eu posso até produzir com sucesso mensagens de um produtor de cliente Java.

    

Answer 1

Provavelmente, isso ocorre porque o driver do sistema não permite que você se conecte ao zookeeper que está sendo executado em outro host. Basta adicionar o host ao seu /etc/hosts .

No Windows, vá para o arquivo C:\Windows\System32\drivers\etc\hosts

e adicione a linha abaixo:
# 192.168.0.2 rhino.acme.com # source server
192.168.0.2 - > ip do zookeeper em execução