CentOS中配置Kafka集群

环境：三台虚拟机Host0，Host1，Host2

Host0：192.168.10.2

Host1:  192.168.10.3

Host2:  192.168.10.4

在三台虚拟机上配置zookeeper，具体配置详见CentOS中配置CDH版本的ZooKeeper

下载kafka：http://kafka.apache.org/downloads.html

我的kafka版本是kafka_2.10-0.8.2.0

在各个kafka节点上解压kafka&进入kafka目录

[root@Host0 ~]# tar xfvz kafka_2.10-0.8.2.0.tgz 
[root@Host0 ~]# cd kafka_2.10-0.8.2.0

在各个kafka节点上配置config/server.propertieswen文件

# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
# 
#    http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# see kafka.server.KafkaConfig for additional details and defaults

############################# Server Basics #############################

# The id of the broker. This must be set to a unique integer for each broker.
broker.id=0

############################# Socket Server Settings #############################

# The port the socket server listens on
port=9092

# Hostname the broker will bind to. If not set, the server will bind to all interfaces
host.name=211.68.36.127

# 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=211.68.36.127

# The port to publish to ZooKeeper for clients to use. If this is not set,
# it will publish the same port that the broker binds to.
#advertised.port=<port accessible by clients>

# The number of threads handling network requests
num.network.threads=3
 
# The number of threads doing disk I/O
num.io.threads=8

# The send buffer (SO_SNDBUF) used by the socket server
socket.send.buffer.bytes=102400

# The receive buffer (SO_RCVBUF) used by the socket server
socket.receive.buffer.bytes=102400

# The maximum size of a request that the socket server will accept (protection against OOM)
socket.request.max.bytes=104857600


############################# Log Basics #############################

# A comma seperated list of directories under which to store log files
log.dirs=/tmp/kafka-logs

# The default number of log partitions per topic. More partitions allow greater
# parallelism for consumption, but this will also result in more files across
# the brokers.
num.partitions=1

# The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.
# This value is recommended to be increased for installations with data dirs located in RAID array.
num.recovery.threads.per.data.dir=1

############################# Log Flush Policy #############################

# Messages are immediately written to the filesystem but by default we only fsync() to sync
# the OS cache lazily. The following configurations control the flush of data to disk. 
# There are a few important trade-offs here:
#    1. Durability: Unflushed data may be lost if you are not using replication.
#    2. Latency: Very large flush intervals may lead to latency spikes when the flush does occur as there will be a lot of data to flush.
#    3. Throughput: The flush is generally the most expensive operation, and a small flush interval may lead to exceessive seeks. 
# The settings below allow one to configure the flush policy to flush data after a period of time or
# every N messages (or both). This can be done globally and overridden on a per-topic basis.

# The number of messages to accept before forcing a flush of data to disk
#log.flush.interval.messages=10000

# The maximum amount of time a message can sit in a log before we force a flush
#log.flush.interval.ms=1000

############################# Log Retention Policy #############################

# The following configurations control the disposal of log segments. The policy can
# be set to delete segments after a period of time, or after a given size has accumulated.
# A segment will be deleted whenever *either* of these criteria are met. Deletion always happens
# from the end of the log.

# The minimum age of a log file to be eligible for deletion
log.retention.hours=168

# A size-based retention policy for logs. Segments are pruned from the log as long as the remaining
# segments don't drop below log.retention.bytes.
#log.retention.bytes=1073741824

# The maximum size of a log segment file. When this size is reached a new log segment will be created.
log.segment.bytes=1073741824

# The interval at which log segments are checked to see if they can be deleted according 
# to the retention policies
log.retention.check.interval.ms=300000

# By default the log cleaner is disabled and the log retention policy will default to just delete segments after their retention expires.
# If log.cleaner.enable=true is set the cleaner will be enabled and individual logs can then be marked for log compaction.
log.cleaner.enable=false

############################# 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.
zookeeper.connect=Host0:2181,Host1:2181,Host2:2181

# Timeout in ms for connecting to zookeeper
zookeeper.connection.timeout.ms=9000

delete.topic.enable = true

注意：

broker.id=0   broker的id，每个kafka节点配置不能一样，可以0,1,2等

host.name=192.168.10.2　　broker的hostname；如果hostname已经设置的话，broker将只会绑定到这个地址上；如果没有设置，它将绑定到所有接口，并发布一份到ZK。每台节点设置成当前节点的IP地址

advertised.host.name=192.168.10.2　　作为broker的hostname发往producer、consumers以及其他brokers。每台节点设置成当前节点的IP地址

log.dirs=/tmp/kafka-logs　　消息文件存储的路径，并不是kafka系统日志存放路径，这里不建议存放在/tmp目录下，因为/tmp目录会定时清理

zookeeper.connect=Host0:2181,Host1:2181,Host2:2181　　指定连接Zookeeper的连接串，此处填写上一节中安装的三个zk节点的ip和端口即可

在各节点中启动kafka

[root@Host0 kafka_2.10-0.8.2.0]# bin/kafka-server-start.sh config/server.properties 

创建topic

[root@Host0 kafka_2.10-0.8.2.0]# bin/kafka-topics.sh --create --zookeeper Host0:2181 --replication-factor 2 --partition 3 --topic my-replicated-topic1

模拟生产者

在任意一个节点上打开终端

[root@Host0 kafka_2.10-0.8.2.0]# bin/kafka-console-producer.sh --broker-list Host0:9092 --topic my-replicated-topic1
[2016-09-05 21:51:57,134] WARN Property topic is not valid (kafka.utils.VerifiableProperties)
hello kafka！

模拟消费者

在任意一个节点上打开终端

[root@Host0 kafka_2.10-0.8.2.0]# bin/kafka-console-consumer.sh --zookeeper Host2:2181 --topic my-replicated-topic1
hello kafka!

host.name和advertised.host.name会有坑，见以下，以下为转载。

此处的坑：

按 照官方文档的说法，advertised.host.name和advertised.port这两个参数用于定义集群向Producer和 Consumer广播的节点host和port，如果不定义的话，会默认使用host.name和port的定义。但在实际应用中，我发现如果不定义 advertised.host.name参数，使用Java客户端从远端连接集群时，会发生连接超时，抛出异 常：org.apache.kafka.common.errors.TimeoutException: Batch Expired

经过debug发现，连接到集群是成功的，但连接到集群后更新回来的集群meta信息却是错误的：
能够看到，metadata中的Cluster信息，节点的hostname是iZ25wuzqk91Z这样的一串数字，而不是实际的ip地址 10.0.0.100和101。iZ25wuzqk91Z其实是远端主机的hostname，这说明在没有配置advertised.host.name 的情况下，Kafka并没有像官方文档宣称的那样改为广播我们配置的host.name，而是广播了主机配置的hostname。远端的客户端并没有配置 hosts，所以自然是连接不上这个hostname的。要解决这一问题，把host.name和advertised.host.name都配置成绝对 的ip地址就可以了。