CDH中Kafka基本指令总结——topic使用与测试producer产生数据、consumer消费数据
一、相关基础内容
Kafka群集中的每个主机都运行一个称为代理的服务器，该服务器存储发送到主题的消息并服务于消费者请求。
首先先看服务器安装kafka的实例信息：
注意：
然后正常kafka的指令是 ： ./bin/kafka-topics.sh --zookeeper cluster2-4:2181 .......
但是使用CDH安装的kafka则不需要全写出此 ./bin/kafka-topics.sh 部分。只许直接写 kafka-topics 即可，这是很重要的一个区别，使用CDH安装的kafka时候要特别注意一下。
具体有哪些指令可以看此路径下：
/opt/cloudera/parcels/KAFKA-4.1.0-1.4.1.0.p0.4/bin
二、topic主题使用
接下来测试topic指令，这里我们要先看CDH中配置的这个ZooKeeper Root的Kafka服务范围为: " /kafka "。
所以我们使用topic的指令格式应该都类似：
kafka-topics --zookeeper cluster2-4:2181/kafka ......
A.创建一个名为 test 的主题（Topic）：
kafka-topics --zookeeper cluster2-4:2181/kafka --create -replication-factor 1 --partitions 3 --topic test
Or
若是上述中的 ZooKeeper Root 的Kafka服务范围为: " / "。则这里的创建主题指令改为：
kafka-topics --zookeeper cluster2-4:2181 --create --replication-factor 1 --partitions 3 --topic test
B.查询现在已经存在的topic：
kafka-topics --zookeeper localhost:2181/kafka --list
C.删除创建的topic：
kafka-topics --zookeeper localhost:2181/kafka --delete --topic test2
拓展：
这里如果直接删除，则会输出 Topic *** is marked for deletion 如上图，如果我们topic中消息堆积的太多，或者kafka所在磁盘空间满了等等，则会需要彻底清理一下kafka topic。
方法一：修改kafaka配置文件server.properties， 添加 delete.topic.enable=true，重启kafka，之后通过kafka命令行就可以直接删除topic。
方法二：通过命令行删除topic： ./bin/kafka-topics.sh --delete --zookeeper {zookeeper server} --topic {topic name}
因为kafaka配置文件中server.properties没有配置delete.topic.enable=true，此时的删除并不是真正的删除，只是把topic标记为：marked for deletion 你可以通过命令：./bin/kafka-topics --zookeeper {zookeeper server} --list 来查看所有topic
方法三：若需要真正删除它，需要登录zookeeper客户端：
zookeeper-client
找到topic所在的目录：
ls /kafka/brokers/topics
执行命令，即可，此时topic被彻底删除：
rmr /kafka/brokers/topics/{topic name}
D.修改topic的分区数：
kafka-topics --zookeeper localhost:2181/kafka --alter --topic test \ partitions 5
F.我们还可以在这里测试分布式是否连接正常：
kafka-topics --zookeeper cluster2-4:2181/kafka --list
kafka-topics --zookeeper cluster2-3:2181/kafka --list
可以看到在2-4这台服务器中，我们后面输入 cluster2-4:2181/kafka 与 cluster2-3:2181/kafka 均可得到统一的信息。
topic指令参数：
Option Description ------ ----------- --alter Alter the number of partitions, replica assignment, and/or configuration for the topic. --bootstrap-server <String: server to REQUIRED: The Kafka server to connect connect to> to. In case of providing this, a direct Zookeeper connection won't be required. --command-config <String: command Property file containing configs to be config property file> passed to Admin Client. This is used only with --bootstrap-server option for describing and altering broker configs. --config <String: name=value> A topic configuration override for the topic being created or altered.The following is a list of valid configurations: cleanup.policy compression.type delete.retention.ms file.delete.delay.ms flush.messages flush.ms follower.replication.throttled. replicas index.interval.bytes leader.replication.throttled.replicas max.message.bytes message.downconversion.enable message.format.version message.timestamp.difference.max.ms message.timestamp.type min.cleanable.dirty.ratio min.compaction.lag.ms min.insync.replicas preallocate retention.bytes retention.ms segment.bytes segment.index.bytes segment.jitter.ms segment.ms unclean.leader.election.enable See the Kafka documentation for full details on the topic configs.It is supported only in combination with -- create if --bootstrap-server option is used. --create Create a new topic. --delete Delete a topic --delete-config <String: name> A topic configuration override to be removed for an existing topic (see the list of configurations under the --config option). Not supported with the --bootstrap-server option. --describe List details for the given topics. --disable-rack-aware Disable rack aware replica assignment --exclude-internal exclude internal topics when running list or describe command. The internal topics will be listed by default --force Suppress console prompts --help Print usage information. --if-exists if set when altering or deleting or describing topics, the action will only execute if the topic exists. Not supported with the --bootstrap- server option. --if-not-exists if set when creating topics, the action will only execute if the topic does not already exist. Not supported with the --bootstrap- server option. --list List all available topics. --partitions <Integer: # of partitions> The number of partitions for the topic being created or altered (WARNING: If partitions are increased for a topic that has a key, the partition logic or ordering of the messages will be affected --replica-assignment <String: A list of manual partition-to-broker broker_id_for_part1_replica1 : assignments for the topic being broker_id_for_part1_replica2 , created or altered. broker_id_for_part2_replica1 : broker_id_for_part2_replica2 , ...> --replication-factor <Integer: The replication factor for each replication factor> partition in the topic being created. --topic <String: topic> The topic to create, alter, describe or delete. It also accepts a regular expression, except for --create option. Put topic name in double quotes and use the '\' prefix to escape regular expression symbols; e. g. "test\.topic". --topics-with-overrides if set when describing topics, only show topics that have overridden configs --unavailable-partitions if set when describing topics, only show partitions whose leader is not available --under-replicated-partitions if set when describing topics, only show under replicated partitions --zookeeper <String: hosts> DEPRECATED, The connection string for the zookeeper connection in the form host:port. Multiple hosts can be given to allow fail-over.
三、测试producer产生数据、consumer消费数据
之前我们创建好topic以后，这里测试一下如何使用kafka中的kafka-console-producer与kafka-console-consumer来生产数据、另一端消费数据。
还需先了解这里 发布-订阅系统中的代理结构：
producer产生数据到Topic中，然后consumer从要消费的Topic中消费数据。
- 首先启动producer：
kafka-console-producer --broker-list cluster2-4:9092 --topic test
在这里输入数据，这些数据会上传到zookeeper中的 /kafka/broker/test 主题中。
kafka-console-producer 生产者的指令参数：
Option Description ------ ----------- --batch-size <Integer: size> Number of messages to send in a single batch if they are not being sent synchronously. (default: 200) --broker-list <String: broker-list> REQUIRED: The broker list string in the form HOST1:PORT1,HOST2:PORT2. --compression-codec [String: The compression codec: either 'none', compression-codec] 'gzip', 'snappy', 'lz4', or 'zstd'. If specified without value, then it defaults to 'gzip' --help Print usage information. --line-reader <String: reader_class> The class name of the class to use for reading lines from standard in. By default each line is read as a separate message. (default: kafka. tools. ConsoleProducer$LineMessageReader) --max-block-ms <Long: max block on The max time that the producer will send> block for during a send request (default: 60000) --max-memory-bytes <Long: total memory The total memory used by the producer in bytes> to buffer records waiting to be sent to the server. (default: 33554432) --max-partition-memory-bytes <Long: The buffer size allocated for a memory in bytes per partition> partition. When records are received which are smaller than this size the producer will attempt to optimistically group them together until this size is reached. (default: 16384) --message-send-max-retries <Integer> Brokers can fail receiving the message for multiple reasons, and being unavailable transiently is just one of them. This property specifies the number of retires before the producer give up and drop this message. (default: 3) --metadata-expiry-ms <Long: metadata The period of time in milliseconds expiration interval> after which we force a refresh of metadata even if we haven't seen any leadership changes. (default: 300000) --producer-property <String: A mechanism to pass user-defined producer_prop> properties in the form key=value to the producer. --producer.config <String: config file> Producer config properties file. Note that [producer-property] takes precedence over this config. --property <String: prop> A mechanism to pass user-defined properties in the form key=value to the message reader. This allows custom configuration for a user- defined message reader. --request-required-acks <String: The required acks of the producer request required acks> requests (default: 1) --request-timeout-ms <Integer: request The ack timeout of the producer timeout ms> requests. Value must be non-negative and non-zero (default: 1500) --retry-backoff-ms <Integer> Before each retry, the producer refreshes the metadata of relevant topics. Since leader election takes a bit of time, this property specifies the amount of time that the producer waits before refreshing the metadata. (default: 100) --socket-buffer-size <Integer: size> The size of the tcp RECV size. (default: 102400) --sync If set message send requests to the brokers are synchronously, one at a time as they arrive. --timeout <Integer: timeout_ms> If set and the producer is running in asynchronous mode, this gives the maximum amount of time a message will queue awaiting sufficient batch size. The value is given in ms. (default: 1000) --topic <String: topic> REQUIRED: The topic id to produce messages to.
接着启动消费者：
kafka-console-consumer --bootstrap-server cluster2-3:9092 --topic test --from-beginning
后面的 --from-beginning 表示从指定主题中有效的起始位移位置开始消费所有分区的消息。
- 消费者消费到topic的数据：
kafka-console-consumer 消费者的指令参数：
Option Description ------ ----------- --bootstrap-server <String: server to REQUIRED: The server(s) to connect to. connect to> --consumer-property <String: A mechanism to pass user-defined consumer_prop> properties in the form key=value to the consumer. --consumer.config <String: config file> Consumer config properties file. Note that [consumer-property] takes precedence over this config. --enable-systest-events Log lifecycle events of the consumer in addition to logging consumed messages. (This is specific for system tests.) --formatter <String: class> The name of a class to use for formatting kafka messages for display. (default: kafka.tools. DefaultMessageFormatter) --from-beginning If the consumer does not already have an established offset to consume from, start with the earliest message present in the log rather than the latest message. --group <String: consumer group id> The consumer group id of the consumer. --help Print usage information. --isolation-level <String> Set to read_committed in order to filter out transactional messages which are not committed. Set to read_uncommittedto read all messages. (default: read_uncommitted) --key-deserializer <String: deserializer for key> --max-messages <Integer: num_messages> The maximum number of messages to consume before exiting. If not set, consumption is continual. --offset <String: consume offset> The offset id to consume from (a non- negative number), or 'earliest' which means from beginning, or 'latest' which means from end (default: latest) --partition <Integer: partition> The partition to consume from. Consumption starts from the end of the partition unless '--offset' is specified. --property <String: prop> The properties to initialize the message formatter. Default properties include: print.timestamp=true|false print.key=true|false print.value=true|false key.separator=<key.separator> line.separator=<line.separator> key.deserializer=<key.deserializer> value.deserializer=<value. deserializer> Users can also pass in customized properties for their formatter; more specifically, users can pass in properties keyed with 'key. deserializer.' and 'value. deserializer.' prefixes to configure their deserializers. --skip-message-on-error If there is an error when processing a message, skip it instead of halt. --timeout-ms <Integer: timeout_ms> If specified, exit if no message is available for consumption for the specified interval. --topic <String: topic> The topic id to consume on. --value-deserializer <String: deserializer for values> --whitelist <String: whitelist> Regular expression specifying whitelist of topics to include for consumption.
- 查看消费数据后的偏移量 kafka-run-class
(1)查看每个Partition的最新偏移量 kafka-run-class kafka.tools.GetOffsetShell --broker-list hadoop:9092 --topic yourTopic --time -1 (2)查看每个Partition的最早的偏移量 kafka-run-class kafka.tools.GetOffsetShell --broker-list hadoop:9092 --topic yourTopic --time -2 (3)查看consumer组内消费的offset kafka-run-class kafka.tools.ConsumerOffsetChecker --zookeeper hadoop:2181 --topic yourTopic
- 获取topic消费组的偏移量
kafka-consumer-offset-checker --zookeeper=localhost:2181 --topic=mytopic --group=my_consumer_group
