Kafka的使用和错误解决
一、下载kafka解压缩：配置环境变量
vim /etc/profile
export KAFKA_HOME=/root/kafka_2.11-1.0.0
export PATH=$PATH:$KAFKA_HOME/bin
source /etc/profile二 、kafka中需要使用zookeeper
-
先将zookeeper启动,如果在伪分布式下,kafka已经集成了zk，在kafka中的config目录下。
可以编辑config/zookeeper.properties修改zookeeper的端口号。后台启动zookeeper：
[root@mail bin]# nohup zookeeper-server-start.sh ../config/zookeeper.properties & - 启动broker
`[root@mail bin]# nohup kafka-server-start.sh ../config/server.properties &`3.测试:模拟消息的消费和生产
（1）创建主题
[root@mail bin]# kafka-topics.sh --create --zookeeper localhost:2281 --topic KafkaTestTopic --partitions 1 --replication-factor 1
Created topic "KafkaTestTopic".（2）创建生产者
[root@mail bin]# kafka-console-producer.sh --topic KafkaTestTopic --broker-list localhost:9092查看server.properties中的#listeners=PLAINTEXT://:9092，获取kafka的端口
（3）创建消费者
[root@mail bin]# kafka-console-consumer.sh --topic KafkaTestTopic --zookeeper localhost:2281三、可能出现的错误：
（1）
[root@mail bin]# kafka-topics.sh --create --zookeeper localhost:2281 --topic KafkaTestTopic --partitions 1 --replication-factor 1
Error while executing topic command : Replication factor: 1 larger than available brokers: 0.
[2018-11-20 16:44:16,269] ERROR org.apache.kafka.common.errors.InvalidReplicationFactorException: Replication factor: 1 larger than available brokers: 0.
(kafka.admin.TopicCommand$)
解决：修改server.properties中的：zookeeper.connect=localhost:2281，让2281端口号和zookeeper.properties中的zookeeper端口号一致，然后重启kafka。**
（2）
kafka.common.KafkaException: fetching topic metadata for topics [Set(KafkaTestTopic)] from broker [ArrayBuffer(BrokerEndPoint(0,123.125.50.7,9092))] failed
at kafka.client.ClientUtils$.fetchTopicMetadata(ClientUtils.scala:77)
at kafka.client.ClientUtils$.fetchTopicMetadata(ClientUtils.scala:98)
at kafka.consumer.ConsumerFetcherManager$LeaderFinderThread.doWork(ConsumerFetcherManager.scala:67)
（3）
[2018-11-20 17:28:53,411] WARN [Producer clientId=console-producer] Error while fetching metadata with correlation id 52 : {KafkaTestTopic=LEADER_NOT_AVAILABLE} (org.apache.kafka.clients.NetworkClient)
[2018-11-20 17:28:53,513] WARN [Producer clientId=console-producer] Error while fetching metadata with correlation id 53 : {KafkaTestTopic=LEADER_NOT_AVAILABLE} (org.apache.kafka.clients.NetworkClient)
[2018-11-20 17:28:53,617] WARN [Producer clientId=console-producer] Error while fetching metadata with correlation id 54 : {KafkaTestTopic=LEADER_NOT_AVAILABLE} (org.apache.kafka.clients.NetworkClient)
[2018-11-20 17:28:53,721] WARN [Producer clientId=console-producer] Error while fetching metadata with correlation id 55 : {KafkaTestTopic=LEADER_NOT_AVAILABLE} (org.apache.kafka.clients.NetworkClient)
解决(2)和（3)的错误:
修改server.properties中的
(1) listeners=PLAINTEXT://localhost:9092
(2) advertised.listeners=PLAINTEXT://localhost:9092