Kafka-安装使用
kafka使用zookeeper保存broker的元数据，所以安装kafka之前需要先安装zookeeper
安装zookeeper
1.准备安装包，解压
此处使用 zookeeper-3.4.9
2.编辑配置文件
在zookeeper根目录下，新建一个数据文件夹data(我用的tmp)，并且在该目录中创建一个myid的文件，用于指明自己的ID（此值为整数即可，后边会用到此值，每个机器对应一个值）
修改conf/zoo.cfg文件
# 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=/Users/FengZhen/Desktop/Hadoop/zookeeper-3.4.9/tmp
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.
#
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
#
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1
server.1=localhost:2888:3888
在这个配置中，initLimit表示用于在从节点与主节点之间建立初始化连接的时间上限
syncLimit表示允许从节点与主节点处于不同步状态的时间上限
这两个值都是tickTime的倍数，所以initLimit是 20 * 2000ms,也就是40s.
配置里还列出了群组中所有服务器的地址，服务器地址遵循server.X=hostname:peerPort:leaderPort格式
X：服务器的ID，它必须是一个整数，不过不一定从0开始，也不要求是连续的，上述myid中的值
Hostname:服务器的机器名或IP地址
peerPort:用于节点间通信的TCP端口
leaderPort:用于首领选举的TCP端口。
客户端只需要通过clientPort就能连接到群组，而群组节点间的通信则需要同时用到这三个端口（peerPort\leaderPort\clientPort）
zookeeper集群被称为群组（Ensemble），zookeeper使用的是一致性协议，所以建议每个群组里应该包含奇数个节点（比如3个、5个等），因为只有当群组里的大多数节点处于可用人数，zookeeper才能处理外部的请求。
3个节点的群组和4个群组的节点允许失效的节点数都是1个，所以3个节点和4个节点起到的作用是一样的。
假设有一个包含5个节点的群组，如果要对群组做一些包括更换节点在内的配置更改，需要依次重启每一个节点。如果群组无法容忍多个节点失效，那么在进行群组维护时就会存在风险。
建议一个群组的节点数不超过7个，因为zookeeper使用了一致性协议，节点过多会降低整个群组的性能。
3.启动zookeeper
bin目录下 ./zkServer.sh start
验证是否启动成功
telnet localhost 2181 连接成功输入srvr
FengZhendeMacBook-Pro:tmp FengZhen$ telnet localhost 2181
Trying ::1...
Connected to localhost.
Escape character is '^]'.
srvr
Zookeeper version: 3.4.9-1757313, built on 08/23/2016 06:50 GMT
Latency min/avg/max: 0/0/0
Received: 1
Sent: 0
Connections: 1
Outstanding: 0
Zxid: 0x3161
Mode: standalone
Node count: 167
安装kafka broker
1.准备安装包，解压
此处用的kafka_2.11-1.0.0
2.配置文件修改
修改conf/server.properties,如下
# 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 address the socket server listens on. It will get the value returned from
# java.net.InetAddress.getCanonicalHostName() if not configured.
# FORMAT:
# listeners = listener_name://host_name:port
# EXAMPLE:
# listeners = PLAINTEXT://your.host.name:9092
#listeners=PLAINTEXT://:9092
# Hostname and port the broker will advertise to producers and consumers. If not set,
# it uses the value for "listeners" if configured. Otherwise, it will use the value
# returned from java.net.InetAddress.getCanonicalHostName().
#advertised.listeners=PLAINTEXT://your.host.name:9092
# Maps listener names to security protocols, the default is for them to be the same. See the config documentation for more details
#listener.security.protocol.map=PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL
# The number of threads that the server uses for receiving requests from the network and sending responses to the network
num.network.threads=3
# The number of threads that the server uses for processing requests, which may include 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
############################# Internal Topic Settings #############################
# The replication factor for the group metadata internal topics "__consumer_offsets" and "__transaction_state"
# For anything other than development testing, a value greater than 1 is recommended for to ensure availability such as 3.
offsets.topic.replication.factor=1
transaction.state.log.replication.factor=1
transaction.state.log.min.isr=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 due to age
log.retention.hours=168
# A size-based retention policy for logs. Segments are pruned from the log unless the remaining
# segments drop below log.retention.bytes. Functions independently of log.retention.hours.
#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
############################# 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=localhost:2181
# Timeout in ms for connecting to zookeeper
zookeeper.connection.timeout.ms=6000
############################# Group Coordinator Settings #############################
# The following configuration specifies the time, in milliseconds, that the GroupCoordinator will delay the initial consumer rebalance.
# The rebalance will be further delayed by the value of group.initial.rebalance.delay.ms as new members join the group, up to a maximum of max.poll.interval.ms.
# The default value for this is 3 seconds.
# We override this to 0 here as it makes for a better out-of-the-box experience for development and testing.
# However, in production environments the default value of 3 seconds is more suitable as this will help to avoid unnecessary, and potentially expensive, rebalances during application startup.
group.initial.rebalance.delay.ms=0
zookeeper.connect设置为localhost:2181,如果有多个，分号拼接
3.启动kafka server
bin/kafka-server-start.sh -daemon ../config/server.properties
4.创建topic
./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic test_topic
5.查看topic详情
./kafka-topics.sh --zookeeper localhost:2181 --describe --topic test_topic
6.在测试主题上发布消息
./kafka-console-producer.sh --broker-list localhost:9092 --topic test_topic
FengZhendeMacBook-Pro:bin FengZhen$ ./kafka-console-producer.sh --broker-list localhost:9092 --topic test_topic
>test
>topic
>2020-03-25
7.在测试主题上读取消息
./kafka-console-consumer.sh --zookeeper localhost:2181 --topic test_topic --from-beginning
FengZhendeMacBook-Pro:bin FengZhen$ ./kafka-console-consumer.sh --zookeeper localhost:2181 --topic test_topic --from-beginning
Using the ConsoleConsumer with old consumer is deprecated and will be removed in a future major release. Consider using the new consumer by passing [bootstrap-server] instead of [zookeeper].
test
topic
2020-03-25
