kafka是否支持服务化 kafka支持哪些语言

1.需要安装JDK，因为Kafka是用Scala语言编码的，而Scala语言就是运行在JVM（Java虚拟机）上边的。要是没有安装好的话，可以在云服务器上直接运行yum install java-1.8.0-openjdk* -y，进行安装。

中间直到会出现一个暂停询问的地方，输入“y”就行，然后出现Complete!才算完成

2.Kafka依赖于Zookeeper，首先需要安装Zookeeper。使用 wget https://archive.apache.org/dist/zookeeper/zookeeper-3.5.8/apache-zookeeper-3.5.8-bin.tar.gz直接在云服务器上下载zookeeper-3.5.8。

https://zookeeper.apache.org/是Zookeeper的官网，https://archive.apache.org/dist/zookeeper/是在国外的官网下载Zookeeper的网址，https://mirror.bit.edu.cn/apache/zookeeper/是国内的一个镜像网站，下载网速会快上不少。

2.1.下载完成之后，使用tar -zxvf apache-zookeeper-3.5.8-bin.tar.gz 解压。

2.2 启动Zookeeper。 cd apache-zookeeper-3.5.8-bin/进入目录下。

cp conf/zoo_sample.cfg conf/zoo.cfg将zoo_sample.cfg拷贝成zoo.cfg，Zookeeper是以conf目录下zoo.cfg为启动的默认文件。

bin/zkServer.sh start打开Zookeeper服务端，发现报错。

bin/zkServer.sh start-foreground读日志，发现报下边的错误：

ERROR [main:ZooKeeperServerMain@79] - Unable to start AdminServer, exiting abnormally
org.apache.zookeeper.server.admin.AdminServer$AdminServerException: Problem starting AdminServer on address 0.0.0.0, port 8080 and command URL /commands
        at org.apache.zookeeper.server.admin.JettyAdminServer.start(JettyAdminServer.java:107)
        at org.apache.zookeeper.server.ZooKeeperServerMain.runFromConfig(ZooKeeperServerMain.java:138)
        at org.apache.zookeeper.server.ZooKeeperServerMain.initializeAndRun(ZooKeeperServerMain.java:106)
        at org.apache.zookeeper.server.ZooKeeperServerMain.main(ZooKeeperServerMain.java:64)
        at org.apache.zookeeper.server.quorum.QuorumPeerMain.initializeAndRun(QuorumPeerMain.java:128)
        at org.apache.zookeeper.server.quorum.QuorumPeerMain.main(QuorumPeerMain.java:82)
Caused by: java.io.IOException: Failed to bind to /0.0.0.0:8080
        at org.eclipse.jetty.server.ServerConnector.openAcceptChannel(ServerConnector.java:346)
        at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:307)
        at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:80)
        at org.eclipse.jetty.server.ServerConnector.doStart(ServerConnector.java:231)
        at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72)
        at org.eclipse.jetty.server.Server.doStart(Server.java:385)
        at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:72)
        at org.apache.zookeeper.server.admin.JettyAdminServer.start(JettyAdminServer.java:103)
        ... 5 more
Caused by: java.net.BindException: Address already in use
        at sun.nio.ch.Net.bind0(Native Method)
        at sun.nio.ch.Net.bind(Net.java:438)
        at sun.nio.ch.Net.bind(Net.java:430)
        at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:225)
        at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
        at org.eclipse.jetty.server.ServerConnector.openAcceptChannel(ServerConnector.java:342)
        ... 12 more
Unable to start AdminServer, exiting abnormally

使用 vim conf/zoo.cfg编辑zoo.cfg文件，将admin.serverPort=8081添到文件里边保存。我的zoo.cfg内容
使用8081、8084和9084这几个端口都报下边的错误：

ERROR [main:ZooKeeperServerMain@83] - Unexpected exception, exiting abnormally
java.net.BindException: Address already in use
        at sun.nio.ch.Net.bind0(Native Method)
        at sun.nio.ch.Net.bind(Net.java:438)
        at sun.nio.ch.Net.bind(Net.java:430)
        at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:225)
        at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
        at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:67)
        at org.apache.zookeeper.server.NIOServerCnxnFactory.configure(NIOServerCnxnFactory.java:687)
        at org.apache.zookeeper.server.ZooKeeperServerMain.runFromConfig(ZooKeeperServerMain.java:143)
        at org.apache.zookeeper.server.ZooKeeperServerMain.initializeAndRun(ZooKeeperServerMain.java:106)
        at org.apache.zookeeper.server.ZooKeeperServerMain.main(ZooKeeperServerMain.java:64)
        at org.apache.zookeeper.server.quorum.QuorumPeerMain.initializeAndRun(QuorumPeerMain.java:128)
        at org.apache.zookeeper.server.quorum.QuorumPeerMain.main(QuorumPeerMain.java:82)

把云服务器重启之后，然后vim conf/zoo.cfg把admin.serverPort改成8081。我的/root/apache-zookeeper-3.5.8-bin/conf目录下的zoo.cfg文件内容如下，供大家参考:

# 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=/tmp/zookeeper
# 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
admin.serverPort=8081

使用bin/zkServer.sh start打开Zookeeper服务端。

使用bin/zkServer.sh status查看状态。

如图中所示，就是开启状态。

bin/zkServer.sh stop是关闭的命令。

而再次使用bin/zkServer.sh status就会出现下边的图片所示：

确保自己的Zookeeper一定要是开启状态。

3.下载安装Kafka。

3.1.使用wget https://archive.apache.org/dist/kafka/2.4.1/kafka_2.11-2.4.1.tgz命令下载kafkakafka_2.11-2.4.1。

https://kafka.apache.org/是Kafka的官网，https://archive.apache.org/dist/kafka/是国外官网提供的Kafka下载网址。https://mirror.bit.edu.cn/apache/kafka/是一个国内Kafka的镜像网站，可以到这里选择自己想要的版本。

3.2.tar -xzf kafka_2.11-2.4.1.tgz进行解压。cd kafka_2.11-2.4.1/进入目录下。pwd显示当前所在目录。

我这里/root/kafka_2.11-2.4.1/config目录下server.properties都是默认的，我没有做任何改变，内容如下：

# 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 separated 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 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 excessive 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

使用bin/kafka-server-start.sh -daemon config/server.properties打开Kafka。“-daemon”表示在后台打开，不在当前控制台输入日志，“config/server.properties”是配置文件。

如果启动成功的话，那么使用bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic text创造一个topic就能成功，显示有“Created topic”等字样就是成功。

bin/kafka-server-stop.sh是关闭的命令，现在是在使用这个命令模拟Kafka开启失败，报错如下：

Error while executing topic command : Replication factor: 1 larger than available brokers: 0.
[2022-05-24 22:32:02,660] ERROR org.apache.kafka.common.errors.InvalidReplicationFactorException: Replication factor: 1 larger than available brokers: 0.
 (kafka.admin.TopicCommand$)