【Kafka一】Kafka入门

这篇文章来自Spark集成Kafka(http://bit1129.iteye.com/blog/2174765)，这里把它单独取出来，作为Kafka的入门吧

 

下载Kafka

 http://mirror.bit.edu.cn/apache/kafka/0.8.1.1/kafka_2.10-0.8.1.1.tgz 
 2.10表示Scala的版本，而0.8.1.1表示Kafka的版本 

 

解压Kafka

惊讶的是Kafka内置了Zookeeper的安装包以及启停Zookeeper的脚本，版本比较低，是3.3.4版本。理论上不应该使用Kafka的版本，因为Zookeeper是个通用分布式配置和协调系统.

实际上，也可以使用Kafka内置的Zookeeper，不过要注意，Zookeeper一般使用3台做集群，如果Kakfa的Broker多于3台，那么就取其中3台运行Zookeeper

 

配置Kafka

 1. 修改配置文件config/server.properties

 

 host.name和avertised.host.name默认是注释掉的，把它打开。一般情况下，不要使用localhost作为host.name，如果使用localhost，远程访问Kakfa服务器容易出现问题。

 

    # Hostname the broker will bind to. If not set, the server will bind to all interfaces  
    host.name=localhost  
      
    # Hostname the broker will advertise to producers and consumers. If not set, it uses the  
    # value for "host.name" if configured.  Otherwise, it will use the value returned from  
    # java.net.InetAddress.getCanonicalHostName().  
    advertised.host.name=localhost  

 

 

2. 配置Zookeeper

    本文使用单独安装的Zookeeper，而不是使用Kafka自带的Zookeeper，Kafka为了能够知道它要连接的Zookeeper地址，配置文件中提供了一系列和Zookeeper相关的配置参数

     除了安装运行独立的Zookeeper，Kafka也可以使用安装包里的Zookeeper，如果Kafka要使用自己的Zookeeper，那么需要在 Kafka的bin目录下启动Zookeeper。因此，如果使用独立的Zookeeper的时候，就无  需启动Kafka下面的Zookeeper了。在 Kafka启动过程中看到有关Zookeeper的日志，这是Kafka作为Zookeeper的客户端正在建立与Zookeeper服务器的通讯

•  config/server.properties

 

  ############################# Zookeeper #############################  
      
    # Zookeeper connection string (see zookeeper docs for details).  
    # This is a comma separated host:port pairs, each corresponding to a zk  
    # server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002".  
    # You can also append an optional chroot string to the urls to specify the  
    # root directory for all kafka znodes.  
      
    //2181是Zookeeper的clientPort  
    zookeeper.connect=localhost:2181  
      
    # Timeout in ms for connecting to zookeeper  
    zookeeper.connection.timeout.ms=1000000  

 

• config/producer.properties

    无相关配置

 

• config/consumer.properties

    # Zookeeper connection string  
    # comma separated host:port pairs, each corresponding to a zk  
    # server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002"  
    zookeeper.connect=127.0.0.1:2181  
      
    # timeout in ms for connecting to zookeeper  
    zookeeper.connection.timeout.ms=1000000

 

启动Zookeeper

1.根据之前Kafka对Zookeeper的配置，Zookeeper应该配置端口2181端口
2. 使用如下命令启动Zookeeper，启动Zookeeper的参数如下：

 

    # The number of milliseconds of each tick  
    tickTime=2000  
    # The number of ticks that the initial   
    # synchronization phase can take  
    initLimit=10  
    # The number of ticks that can pass between   
    # sending a request and getting an acknowledgement  
    syncLimit=5  
    # the directory where the snapshot is stored.  
    # do not use /tmp for storage, /tmp here is just   
    # example sakes.  
    dataDir=/home/hadoop/software/zookeeper-3.4.6/data  
    # the port at which the clients will connect  
    clientPort=2181  

 

 启动Kafka

1.启动Kafka(需要指定server.properties）

 

 [hadoop@hadoop kafka_2.10-0.8.1.1]$ bin/kafka-server-start.sh config/server.properties  

 

2. 启动日志

 

2015-01-11 01:11:12,490] INFO Verifying properties (kafka.utils.VerifiableProperties)  
    ////broker.id是在server.properties中定义的
    [2015-01-11 01:11:12,558] INFO Property broker.id is overridden to 0 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,558] INFO Property log.cleaner.enable is overridden to false (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,558] INFO Property log.dirs is overridden to /tmp/kafka-logs (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,558] INFO Property log.retention.check.interval.ms is overridden to 60000 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,559] INFO Property log.retention.hours is overridden to 168 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,559] INFO Property log.segment.bytes is overridden to 536870912 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,559] INFO Property num.io.threads is overridden to 8 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,559] INFO Property num.network.threads is overridden to 2 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,559] INFO Property num.partitions is overridden to 2 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,559] INFO Property port is overridden to 9092 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,559] INFO Property socket.receive.buffer.bytes is overridden to 1048576 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,560] INFO Property socket.request.max.bytes is overridden to 104857600 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,560] INFO Property socket.send.buffer.bytes is overridden to 1048576 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,560] INFO Property zookeeper.connect is overridden to localhost:2181 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,560] INFO Property zookeeper.connection.timeout.ms is overridden to 1000000 (kafka.utils.VerifiableProperties)  
    [2015-01-11 01:11:12,607] INFO [Kafka Server 0], starting (kafka.server.KafkaServer)  
    [2015-01-11 01:11:12,609] INFO [Kafka Server 0], Connecting to zookeeper on localhost:2181 (kafka.server.KafkaServer)  
    [2015-01-11 01:11:12,640] INFO Client environment:zookeeper.version=3.3.3-1203054, built on 11/17/2011 05:47 GMT (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:host.name=hadoop.master (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:java.version=1.7.0_67 (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:java.vendor=Oracle Corporation (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:java.home=/home/hadoop/software/jdk1.7.0_67/jre (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:java.class.path=:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../core/build/dependant-libs-2.8.0/*.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../perf/build/libs//kafka-perf_2.8.0*.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../clients/build/libs//kafka-clients*.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../examples/build/libs//kafka-examples*.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../contrib/hadoop-consumer/build/libs//kafka-hadoop-consumer*.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../contrib/hadoop-producer/build/libs//kafka-hadoop-producer*.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/jopt-simple-3.2.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/kafka_2.10-0.8.1.1.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/kafka_2.10-0.8.1.1-javadoc.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/kafka_2.10-0.8.1.1-scaladoc.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/kafka_2.10-0.8.1.1-sources.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/log4j-1.2.15.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/metrics-core-2.2.0.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/scala-library-2.10.1.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/slf4j-api-1.7.2.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/snappy-java-1.0.5.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/zkclient-0.3.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../libs/zookeeper-3.3.4.jar:/home/hadoop/software/kafka_2.10-0.8.1.1/bin/../core/build/libs/kafka_2.8.0*.jar (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:java.io.tmpdir=/tmp (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:java.compiler=<NA> (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:os.name=Linux (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:os.arch=amd64 (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:os.version=3.10.0-123.el7.x86_64 (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:user.name=hadoop (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:user.home=/home/hadoop (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,640] INFO Client environment:user.dir=/home/hadoop/software/kafka_2.10-0.8.1.1 (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,641] INFO Initiating client connection, connectString=localhost:2181 sessionTimeout=6000 watcher=org.I0Itec.zkclient.ZkClient@7a50a6d4 (org.apache.zookeeper.ZooKeeper)  
    [2015-01-11 01:11:12,643] INFO Starting ZkClient event thread. (org.I0Itec.zkclient.ZkEventThread)  
    [2015-01-11 01:11:12,706] INFO Opening socket connection to server localhost/127.0.0.1:2181 (org.apache.zookeeper.ClientCnxn)  
    [2015-01-11 01:11:12,716] INFO Socket connection established to localhost/127.0.0.1:2181, initiating session (org.apache.zookeeper.ClientCnxn)  
    [2015-01-11 01:11:12,756] INFO Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x14ad79bb13d0000, negotiated timeout = 6000 (org.apache.zookeeper.ClientCnxn)  
    [2015-01-11 01:11:12,759] INFO zookeeper state changed (SyncConnected) (org.I0Itec.zkclient.ZkClient)  
    ////log.dirs不存在，先创建
    [2015-01-11 01:11:12,919] INFO Log directory '/tmp/kafka-logs' not found, creating it. (kafka.log.LogManager)  
    [2015-01-11 01:11:12,948] INFO Starting log cleanup with a period of 60000 ms. (kafka.log.LogManager)  
    [2015-01-11 01:11:12,975] INFO Starting log flusher with a default period of 9223372036854775807 ms. (kafka.log.LogManager)  
    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.  
    [2015-01-11 01:11:13,039] INFO Awaiting socket connections on 0.0.0.0:9092. (kafka.network.Acceptor)  
    [2015-01-11 01:11:13,063] INFO [Socket Server on Broker 0], Started (kafka.network.SocketServer)  
    [2015-01-11 01:11:13,163] INFO Will not load MX4J, mx4j-tools.jar is not in the classpath (kafka.utils.Mx4jLoader$) 
    ///只有1台Zookeeper服务器，因此serverid为0的Zookeeper成为leader 
    [2015-01-11 01:11:13,219] INFO 0 successfully elected as leader (kafka.server.ZookeeperLeaderElector)  
    ////注册Broker到Zookeeper的/brokers/ids/0节点
    [2015-01-11 01:11:13,367] INFO Registered broker 0 at path /brokers/ids/0 with address hadoop.master:9092. (kafka.utils.ZkUtils$)  
    [2015-01-11 01:11:13,379] INFO [Kafka Server 0], started (kafka.server.KafkaServer)  
    [2015-01-11 01:11:13,486] INFO New leader is 0 (kafka.server.ZookeeperLeaderElector$LeaderChangeListener)  

 

 

Kafka简单测试

1.创建一个topic

参数信息：Zookeeper的信息，Topic的名字，Topic的Partition数，复制因子(复制因子必须小于等于Broker数目）

 

 

    ///创建一个Topic，取名为test
    [hadoop@hadoop kafka_2.10-0.8.1.1]$ bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1  --topic test  
    Created topic "test".  
    ///列出创建的Topic，这里只有一个test  
    [hadoop@hadoop kafka_2.10-0.8.1.1]$ bin/kafka-topics.sh --list --zookeeper localhost:2181  
    test  

 

2. Producer创建消息
    启动时，除了打印SLF4J之外，没有别的。下面可以直接输入生产的数据（生产消息时不需要指定Partition，Kafka自动做Partition路由，每个Partition都是有Lead Partition和Follower Partitions组成，Lead Partition负责读写，而Follower Partitions只做复制，在Lead Partition挂了之后，自动做Failover）

 

    [hadoop@hadoop kafka_2.10-0.8.1.1]$ bin/kafka-console-producer.sh --broker-list localhost:9092 --topic test  
    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 mesage  
    This is a test  

 

3. Consumer消费消息

    启动时，除了打印SLF4J之外，没有别的

 

   --from-beginning实际上是指定offset的读取策略。

对于smallest和largest还是理解不到位，smallest和largest策略表示Zookeeper上的offset还没有初始化为正确值时，如何初始化offset的问题？试想，Producer生产了一批消息到Kafka中，但是Kafka尚未由任何Consumer读取，而Kafka的Offset是由Consumer进行初始化和赋值的，因此此时的Zookeeper上的offset并没有预期的0(0表示尚未读取过)，而是一个不正确的随机数，那么Consumer来读取消息时，是从头开始读还是从最大的位置等待Producer创建消息后再读取，此时就产生了两个选择，smallest表示从头读，largest表示从最大位置读

 

auto.offset.reset（默认是largest）:

What to do when there is no initial offset in ZooKeeper or if an offset is out of range:
* smallest : automatically reset the offset to the smallest offset
* largest : automatically reset the offset to the largest offset
* anything else: throw exception to the consumer

 

 

    [hadoop@hadoop kafka_2.10-0.8.1.1]$ bin/kafka-console-consumer.sh --zookeeper localhost:2181 --topic test --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 mesage  
    This is a test 

 

4.此时在Producer终端输入内容，在Consumer终端可以立即收到