前言

最近在部署kafka单节点时遇到的问题，想着自己弄个单节点演示以下， 好家伙，单启动的时候就报了很多错误；为防止在坑，故将错误信息记录下来；以防万一！

kafka版本

2.4.1

部署环境

阿里云服务器，系统为centos 7.9

解决kafka启动报错 ：Socket server failed to bind to 123.57.207.179:9092: 无法指定被请求的地址.

控制台整体错误信息如下

[2021-09-14 10:59:11,134] ERROR [KafkaServer id=0] Fatal error during KafkaServer startup. Prepare to shutdown (kafka.server.KafkaServer)
org.apache.kafka.common.KafkaException: Socket server failed to bind to 123.57.207.179:9092: 无法指定被请求的地址.
        at kafka.network.Acceptor.openServerSocket(SocketServer.scala:632)
        at kafka.network.Acceptor.<init>(SocketServer.scala:508)
        at kafka.network.SocketServer.kafka$network$SocketServer$$createAcceptor(SocketServer.scala:271)
        at kafka.network.SocketServer$$anonfun$createDataPlaneAcceptorsAndProcessors$1.apply(SocketServer.scala:240)
        at kafka.network.SocketServer$$anonfun$createDataPlaneAcceptorsAndProcessors$1.apply(SocketServer.scala:238)
        at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
        at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:48)
        at kafka.network.SocketServer.createDataPlaneAcceptorsAndProcessors(SocketServer.scala:238)
        at kafka.network.SocketServer.startup(SocketServer.scala:121)
        at kafka.server.KafkaServer.startup(KafkaServer.scala:263)
        at kafka.server.KafkaServerStartable.startup(KafkaServerStartable.scala:44)
        at kafka.Kafka$.main(Kafka.scala:84)
        at kafka.Kafka.main(Kafka.scala)
Caused by: java.net.BindException: 无法指定被请求的地址
        at sun.nio.ch.Net.bind0(Native Method)
        at sun.nio.ch.Net.bind(Net.java:433)
        at sun.nio.ch.Net.bind(Net.java:425)
        at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223)
        at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
        at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:67)
        at kafka.network.Acceptor.openServerSocket(SocketServer.scala:628)
        ... 12 more

原因

其实是kafka的监听地址有问题，不知道为啥，server.properties配置文件中的listeners=PLAINTEXT://123.57.66.105:9092选项
一定要使用内网ip，我这边使用的是公网ip地址（我用的是阿里云服务器），

解决步骤

1、先获取当前系统的内网ip地址

[root@iZ2zee7r7jat94g6t1guhtZ ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.21.227.173  netmask 255.255.240.0  broadcast 172.21.239.255
        inet6 fe80::216:3eff:fe06:1775  prefixlen 64  scopeid 0x20<link>
        ether 00:16:3e:06:17:75  txqueuelen 1000  (Ethernet)
        RX packets 4053113  bytes 1013685895 (966.7 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 3283585  bytes 722364027 (688.9 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

可以看到。内网ip地址为：172.21.227.173

2、重新设置kafka的server.properties配置文件

接下来，重新设置kafka的server.properties配置文件，将公网ip改为内网ip，使用编辑器打开server.properties

vim /usr/local/kafka/kafka_2.11-2.4.1/server.properties

找到listeners=PLAINTEXT://123.57.66.105:9092，将其改为内网ip

listeners=PLAINTEXT://172.21.227.173:9092

3、重新启动kafka

启动kafka ,-daemon表示守护进程，也就是后台运行

/usr/local/kafka/kafka_2.11-2.4.1/bin/kafka-server-start.sh -daemon /usr/local/kafka/kafka_2.11-2.4.1/config/server.properties

大功告成

解决报错 Timed out waiting for connection while in state: CONNECTING

在启动kafka时报错如下信息

[2021-09-14 11:43:55,494] ERROR Fatal error during KafkaServer startup. Prepare to shutdown (kafka.server.KafkaServer)
kafka.zookeeper.ZooKeeperClientTimeoutException: Timed out waiting for connection while in state: CONNECTING
        at kafka.zookeeper.ZooKeeperClient$$anonfun$kafka$zookeeper$ZooKeeperClient$$waitUntilConnected$1.apply$mcV$sp(ZooKeeperClient.scala:259)
        at kafka.zookeeper.ZooKeeperClient$$anonfun$kafka$zookeeper$ZooKeeperClient$$waitUntilConnected$1.apply(ZooKeeperClient.scala:255)
        at kafka.zookeeper.ZooKeeperClient$$anonfun$kafka$zookeeper$ZooKeeperClient$$waitUntilConnected$1.apply(ZooKeeperClient.scala:255)
        at kafka.utils.CoreUtils$.inLock(CoreUtils.scala:253)
        at kafka.zookeeper.ZooKeeperClient.kafka$zookeeper$ZooKeeperClient$$waitUntilConnected(ZooKeeperClient.scala:255)
        at kafka.zookeeper.ZooKeeperClient.<init>(ZooKeeperClient.scala:113)
        at kafka.zk.KafkaZkClient$.apply(KafkaZkClient.scala:1857)
        at kafka.server.KafkaServer.kafka$server$KafkaServer$$createZkClient$1(KafkaServer.scala:374)
        at kafka.server.KafkaServer.initZkClient(KafkaServer.scala:399)
        at kafka.server.KafkaServer.startup(KafkaServer.scala:207)
        at kafka.server.KafkaServerStartable.startup(KafkaServerStartable.scala:44)
        at kafka.Kafka$.main(Kafka.scala:84)
        at kafka.Kafka.main(Kafka.scala)

原因

错误很明显，就是超时了，仔细看，里面报的错误是ZooKeeperClientTimeoutException异常,这就是代表kafka在连接zk的时候超时了；一开始以为是zk挂了，为了解决这个问题，我特意去看了zookeeper，发现是正在运行的，并没有出问题；后来才发现是kafka的配置错了；在kafka的server.properties配置文件中，有一个配置为：zookeeper.connect=123.57.207.179:2181，这个配置将kafka添加zk的节点上，但是我这里配的是外网ip（我用的是阿里云服务器），要解决这个问题其实很简单，只需要将外网ip改为内网ip即可；

解决步骤

1、获取内网ip

通过以下命令即可查看内网ip地址

ifconfig
# 运行后，得到的内网ip为： 172.21.227.173

2、重新设置kafka的server.properties配置文件

接下来，重新设置kafka的server.properties配置文件，将公网ip改为内网ip，使用编辑器打开server.properties

vim /usr/local/kafka/kafka_2.11-2.4.1/server.properties

找到zookeeper.connect=123.57.207.179:2181，将其改为内网ip

zookeeper.connect=172.21.227.173:2181

3、重新启动kafka

大功告成

java连接kafka超时 ZkTimeoutException: Unable to connect to zookeeper server within timeout: 6000

遇到这种问题有如下解决方案
1、 检查zk是否运行
2、 检查linux是否开放了9092端口（kafka默认端口）
3、 检查阿里云服务器是否配置了安全组（我的就是这个问题导致的），安全组可以配置能被外网访问的端口以及黑白名单；安全组配置如下：