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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
（一）使用kafka自带的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 &
`[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（二）使用非kafka自带的zookeeper
使用zookeeper（非kafka自带）
[root@mail zookeeper-3.4.10]# bin/zkServer.sh start conf/zoo.cfg
ZooKeeper JMX enabled by default
Using config: conf/zoo.cfg
Starting zookeeper ... STARTED
（1） 创建主题
[root@mail kafka_2.11-1.0.0]# bin/kafka-topics.sh --create --zookeeper localhost:2181 --topic secondTopic --partitions 1 --replication-factor 1
Created topic "secondTopic".
（2）kafka启动
[root@mail kafka_2.11-1.0.0]# nohup bin/kafka-server-start.sh config/server.properties &
（3）kafka生产者
[root@mail kafka_2.11-1.0.0]# kafka-console-producer.sh --topic KafkaTestTopic --broker-list localhost:9092
（4）kafka消费者
[root@mail kafka_2.11-1.0.0]# bin/kafka-console-consumer.sh --topic KafkaTestTopic --zookeeper localhost:2181
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].
（5）查看kafka中的数据
[root@mail kafka_2.11-1.0.0]# ls
bin config libs LICENSE logs logs-kafka nohup.out NOTICE site-docs
[root@mail kafka_2.11-1.0.0]# cd logs-kafka/ #kafka中的数据存储目录
##这个目录是在kafka的config/server.properties文件中进行配置的
log.dirs=/root/kafka/kafka_2.11-1.0.0/logs-kafka
[root@mail logs-kafka]# ls #查看kafka中的主题
cleaner-offset-checkpoint __consumer_offsets-20 __consumer_offsets-33 __consumer_offsets-46 kafka_test-0
__consumer_offsets-0 __consumer_offsets-21 __consumer_offsets-34 __consumer_offsets-47 KafkaTestTopic-0
__consumer_offsets-1 __consumer_offsets-22 __consumer_offsets-35 __consumer_offsets-48 log-start-offset-checkpoint
__consumer_offsets-10 __consumer_offsets-23 __consumer_offsets-36 __consumer_offsets-49 meta.properties
__consumer_offsets-11 __consumer_offsets-24 __consumer_offsets-37 __consumer_offsets-5 My_LOVE_TOPIC-0
__consumer_offsets-12 __consumer_offsets-25 __consumer_offsets-38 __consumer_offsets-6 mytopic-0
__consumer_offsets-13 __consumer_offsets-26 __consumer_offsets-39 __consumer_offsets-7 recovery-point-offset-checkpoint
__consumer_offsets-14 __consumer_offsets-27 __consumer_offsets-4 __consumer_offsets-8 replication-offset-checkpoint
__consumer_offsets-15 __consumer_offsets-28 __consumer_offsets-40 __consumer_offsets-9 stock-quotation-0
__consumer_offsets-16 __consumer_offsets-29 __consumer_offsets-41 hello-0 stock-quotation-avro-0
__consumer_offsets-17 __consumer_offsets-3 __consumer_offsets-42 hello-1 stock-quotation-partition-0
__consumer_offsets-18 __consumer_offsets-30 __consumer_offsets-43 hello-2 TEST-TOPIC-0
__consumer_offsets-19 __consumer_offsets-31 __consumer_offsets-44 hello-3
__consumer_offsets-2 __consumer_offsets-32 __consumer_offsets-45 hello-4
[root@mail logs-kafka]# cd KafkaTestTopic-0/ #查看kakfa的主题为KafkaTestTopic的0号分区
[root@mail KafkaTestTopic-0]# ls
00000000000000000000.index 00000000000000000000.timeindex leader-epoch-checkpoint
00000000000000000000.log 00000000000000000063.snapshot
[root@mail KafkaTestTopic-0]# tail -f 000000000000000000.log #kafka中的数据存储文件
（6）修改kafka的分区数,观察kafka的变化
## 修改kafka分区数
[root@mail kafka_2.11-1.0.0]# bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic KafkaTestTopic --partitions 3
WARNING: If partitions are increased for a topic that has a key, the partition logic or ordering of the messages will be affected
Adding partitions succeeded!
[root@mail kafka_2.11-1.0.0]# ls
bin config libs LICENSE logs logs-kafka nohup.out NOTICE site-docs
[root@mail kafka_2.11-1.0.0]# cd logs-kafka/
#发现出现kakfa的主题为KafkaTestTopic的0号分区,1号分区,2号分区,总共3个分区
[root@mail logs-kafka]# ls
cleaner-offset-checkpoint __consumer_offsets-20 __consumer_offsets-33 __consumer_offsets-46 kafka_test-0
__consumer_offsets-0 __consumer_offsets-21 __consumer_offsets-34 __consumer_offsets-47 KafkaTestTopic-0
__consumer_offsets-1 __consumer_offsets-22 __consumer_offsets-35 __consumer_offsets-48 KafkaTestTopic-1
__consumer_offsets-10 __consumer_offsets-23 __consumer_offsets-36 __consumer_offsets-49 KafkaTestTopic-2
__consumer_offsets-11 __consumer_offsets-24 __consumer_offsets-37 __consumer_offsets-5 log-start-offset-checkpoint
__consumer_offsets-12 __consumer_offsets-25 __consumer_offsets-38 __consumer_offsets-6 meta.properties
__consumer_offsets-13 __consumer_offsets-26 __consumer_offsets-39 __consumer_offsets-7 My_LOVE_TOPIC-0
__consumer_offsets-14 __consumer_offsets-27 __consumer_offsets-4 __consumer_offsets-8 mytopic-0
__consumer_offsets-15 __consumer_offsets-28 __consumer_offsets-40 __consumer_offsets-9 recovery-point-offset-checkpoint
__consumer_offsets-16 __consumer_offsets-29 __consumer_offsets-41 hello-0 replication-offset-checkpoint
__consumer_offsets-17 __consumer_offsets-3 __consumer_offsets-42 hello-1 stock-quotation-0
__consumer_offsets-18 __consumer_offsets-30 __consumer_offsets-43 hello-2 stock-quotation-avro-0
__consumer_offsets-19 __consumer_offsets-31 __consumer_offsets-44 hello-3 stock-quotation-partition-0
__consumer_offsets-2 __consumer_offsets-32 __consumer_offsets-45 hello-4 TEST-TOPIC-0
[root@mail KafkaTestTopic-1]# ls #查看kakfa的主题为KafkaTestTopic的1号分区
00000000000000000000.index 00000000000000000000.log 00000000000000000000.timeindex leader-epoch-checkpoint
[root@mail KafkaTestTopic-1]# tail -f 00000000000000000000.log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
I、listeners=PLAINTEXT://localhost:9092
II、 advertised.listeners=PLAINTEXT://localhost:9092
(4) [2018-11-29 09:44:35,275] WARN [Producer clientId=console-producer] Connection to node -1 could not be established. Broker may not be available. (org.apache.kafka.clients.NetworkClient)
解决：可能的原因：kafka未启动，重启启动kafka。
kafka中查看zookeeper状态：
bin/zookeeper-shell.sh localhost:2181 <<< "get /brokers/ids/0"
（5）Failed to find leader for Set(KafkaTestTopic-0) (kafka.consumer.ConsumerFetcherManager$LeaderFinderThread)
解决：修改kafka配置文件
[root@mail config]# vim server.properties
修改：advertised.host.name=正确的IP地址
四、Kafka相关操作
（1）查看有哪些主题
[root@mail ~]# kafka-topics.sh --describe --zookeeper localhost:2281
Topic:KafkaTestTopic PartitionCount:1 ReplicationFactor:1 Configs:
Topic: KafkaTestTopic Partition: 0 Leader: 0 Replicas: 0 Isr: 0
在kafka中每个分区都有一个编号，从0开始；
在kafka中如果有多个副本的话，就会存在leader与follower的关系；Leader表示领导,Leader:0表示当前这个副本为leader所在的broker是哪一个。
（2）只看主题名称
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --list --zookeeper localhost:2281
KafkaTestTopic
(3)查看指定主题的信息
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --describe --zookeeper localhost:2281 --topic KafkaTestTopic
（4）查看指定的topic是否存在
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --list --zookeeper localhost:2281 --topic KafkaTestTopic
或
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --list --zookeeper localhost:2281 | grep KafkaTestTopic
(5) 修改主题的分区数
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --zookeeper localhost:2281 --alter --topic KafkaTestTopic --partitions 3
WARNING: If partitions are increased for a topic that has a key, the partition logic or ordering of the messages will be affected
Adding partitions succeeded!
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --describe --zookeeper localhost:2281 --topic KafkaTestTopic
Topic:KafkaTestTopic PartitionCount:3 ReplicationFactor:1 Configs:
Topic: KafkaTestTopic Partition: 0 Leader: 0 Replicas: 0 Isr: 0
Topic: KafkaTestTopic Partition: 1 Leader: 0 Replicas: 0 Isr: 0
Topic: KafkaTestTopic Partition: 2 Leader: 0 Replicas: 0 Isr: 0
（6）修改配置项
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --zookeeper localhost:2281 --alter --topic KafkaTestTopic --config flush.messages=1
WARNING: Altering topic configuration from this script has been deprecated and may be removed in future releases.
Going forward, please use kafka-configs.sh for this functionality
Updated config for topic "KafkaTestTopic".
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --describe --zookeeper localhost:2281 --topic KafkaTestTopic
Topic:KafkaTestTopic PartitionCount:3 ReplicationFactor:1 Configs:flush.messages=1
Topic: KafkaTestTopic Partition: 0 Leader: 0 Replicas: 0 Isr: 0
Topic: KafkaTestTopic Partition: 1 Leader: 0 Replicas: 0 Isr: 0
Topic: KafkaTestTopic Partition: 2 Leader: 0 Replicas: 0 Isr: 0
（7）删除配置项
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --zookeeper localhost:2281 --alter --topic KafkaTestTopic --delete-config flush.messages
WARNING: Altering topic configuration from this script has been deprecated and may be removed in future releases.
Going forward, please use kafka-configs.sh for this functionality
Updated config for topic "KafkaTestTopic".
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --describe --zookeeper localhost:2281 --topic KafkaTestTopic
Topic:KafkaTestTopic PartitionCount:3 ReplicationFactor:1 Configs:
Topic: KafkaTestTopic Partition: 0 Leader: 0 Replicas: 0 Isr: 0
Topic: KafkaTestTopic Partition: 1 Leader: 0 Replicas: 0 Isr: 0
Topic: KafkaTestTopic Partition: 2 Leader: 0 Replicas: 0 Isr: 0
（8）删除主题
[root@mail kafka_2.11-1.0.0]# kafka-topics.sh --zookeeper localhost:2281 --delete --topic KafkaTestTopic
注意：删除只是标记删除；当服务器重启就会删除已标记的topic，这个和kafka的版本有关。五、Java中Kakfa配置
（1）.Java中使用kafka的Producer端配置
Properties props=new Properties();
// Kafka服务端的主机名和端口号,多个的话,使用逗号分隔
props.put("bootstrap.servers","ip:9092");
// 等待所有副本节点的应答
props.put("acks", "all");
// 消息发送大尝试次数
props.put("retries",0);
// 一批消息处理大小
props.put("batch.size","16384");
// 请求延时
props.put("linger.ms",1);
// 发送缓存区内存大小
props.put("buffer.memory", 33554430);
// key序列化
props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
// value序列化
props.put("value.serializer","org.apache.kafka.common.serialization.StringSerializer");
（2）.Java中使用kafka的Consumer端配置
Properties props=new Properties();
// 定义kakfa 服务的地址,不需要将所有broker指定上
props.put("bootstrap.servers","ip:9092");
// 制定consumer group
props.put("group.id","test1");
// 是否自动确认offset
props.put("enable.auto.commit", "true");
// 自动确认offset的时间间隔
props.put("auto.commit.interval.ms", "1000");
// key的序列化类
props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
// value的序列化类
props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");另外有需要云服务器可以了解下创新互联scvps.cn，海内外云服务器15元起步，三天无理由+7*72小时售后在线，公司持有idc许可证，提供“云服务器、裸金属服务器、高防服务器、香港服务器、美国服务器、虚拟主机、免备案服务器”等云主机租用服务以及企业上云的综合解决方案，具有“安全稳定、简单易用、服务可用性高、性价比高”等特点与优势，专为企业上云打造定制，能够满足用户丰富、多元化的应用场景需求。