环境是linux，4台机器，版本3.6，kafka安装在node 1 2 3 上，zookeeper安装在node2 3 4上。
安装好kafka，进入bin目录，可以看到有很多sh文件，是我们执行命令的基础。
启动kafka，下面的命令的后面带的配置文件的相对路径
kafka-server-start.sh ./server.properties
遇到不熟悉的sh文件，直接输入名字并回车，就会提示你可用的命令参数。如果参数用错了，kafka也会提示你相应的错误。
[root@localhost bin]# kafka-topics.sh
Create, delete, describe, or change a topic.
Option Description
------ -----------
--alter Alter the number of partitions and replica assignment. Update the configuration of an existing topic via --alter is no longer supported here (the kafka-configs CLI supports altering topic configs with a -- bootstrap-server option).
--at-min-isr-partitions if set when describing topics, only show partitions whose isr count is equal to the configured minimum.
--bootstrap-server <String: server to REQUIRED: The Kafka server to connect connect to> to.
--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 local.retention.bytes local.retention.ms max.compaction.lag.ms max.message.bytes message.downconversion.enable message.format.version message.timestamp.after.max.ms message.timestamp.before.max.ms message.timestamp.difference.max.ms message.timestamp.type min.cleanable.dirty.ratio min.compaction.lag.ms min.insync.replicas preallocate remote.storage.enable 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 (the kafka-configs CLI supports altering topic configs with a --bootstrap-server option).
--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.
--exclude-internal exclude internal topics when running list or describe command. The internal topics will be listed by default
--help Print usage information.
--if-exists if set when altering or deleting or describing topics, the action will only execute if the topic exists.
--if-not-exists if set when creating topics, the action will only execute if the topic does not already exist.
--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). If not supplied for create, defaults to the cluster default.
--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. If not supplied, defaults to the cluster default.
--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".
--topic-id <String: topic-id> The topic-id to describe.This is used only with --bootstrap-server option for describing topics.
--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-min-isr-partitions if set when describing topics, only show partitions whose isr count is less than the configured minimum.
--under-replicated-partitions if set when describing topics, only show under replicated partitions
--version Display Kafka version.
如这里，我们创建一个topic名为test。
kafka-topics.sh --create --topic test --bootstrap-server node1:9092 --partitions 2 --replication-factor 2
Created topic test.连接其中node1上的kafka获得metedata里的topic列表
[root@localhost bin]# kafka-topics.sh --list --bootstrap-server node1:9092
test查看某个topic的细节
[root@localhost bin]# kafka-topics.sh --describe --topic test --bootstrap-server node1:9092
Topic: test TopicId: WgjG4Ou_Q7iQvzgipRgzjg PartitionCount: 2 ReplicationFactor: 2 Configs: Topic: test Partition: 0 Leader: 2 Replicas: 2,1 Isr: 2,1Topic: test Partition: 1 Leader: 3 Replicas: 3,2 Isr: 3,2在其中的一台机器上起一个生产者，在其他两台机器上起2个消费者，都在同一个组里。
[root@localhost bin]# kafka-console-producer.sh --broker-list node1:9092 --topic test
>hello 03
>1
>2
>3
>4
>5
>6
>7
>8可以看到同一个组内，如果组内消费者注册情况不变化有且只有同一个consumer能够消费数据。可以满足对于消息要求顺序性，不能并发消费的情况。
[root@localhost bin]# kafka-console-consumer.sh --bootstrap-server node1:9092 --topic test --group msb
hello 03
1
2
3
4
5
6
7
8查看某个组内的情况
[root@localhost bin]# kafka-consumer-groups.sh --bootstrap-server node2:9092 --group msb --describeGROUP TOPIC PARTITION CURRENT-OFFSET LOG-END-OFFSET LAG CONSUMER-ID HOST CLIENT-ID
msb test 1 24 24 0 console-consumer-4987804d-6e59-4f4d-9952-9afb9aff6cbe /192.168.184.130 console-consumer
msb test 0 0 0 0 console-consumer-242992e4-7801-4a38-a8f3-8b44056ed4b6 /192.168.184.130 console-consumer最后看一下zk中的情况吧。
zk根目录下多了一个kafka节点
[zk: localhost:2181(CONNECTED) 1] ls /
[kafka, node1, node6, node7, testLock, zookeeper]
kafka下面有很多metedata信息，包含在这些节点中，如，，
[zk: localhost:2181(CONNECTED) 2] ls /kafka
[admin, brokers, cluster, config, consumers, controller, controller_epoch, feature, isr_change_notification, latest_producer_id_block, log_dir_event_notification]
#集群id
[zk: localhost:2181(CONNECTED) 3] ls /kafka/cluster
[id]
[zk: localhost:2181(CONNECTED) 5] get /kafka/cluster/id
{"version":"1","id":"8t14lxoAS1SdXapY6ysw_A"}
#controller的id
[zk: localhost:2181(CONNECTED) 6] get /kafka/controller
{"version":2,"brokerid":3,"timestamp":"1698841142070","kraftControllerEpoch":-1}可以看到topics中有一个__consumer_offsets，是kafka用来存储offset的topic。
[zk: localhost:2181(CONNECTED) 10] ls /kafka/brokers/topics
[__consumer_offsets, test]
[zk: localhost:2181(CONNECTED) 12] get /kafka/brokers/topics/__consumer_offsets
{"partitions":{"44":[1],"45":[2],"46":[3],"47":[1],"48":[2],"49":[3],"10":[3],"11":[1],"12":[2],"13":[3],"14":[1],"15":[2],"16":[3],"17":[1],"18":[2],"19":[3],"0":[2],"1":[3],"2":[1],"3":[2],"4":[3],"5":[1],"6":[2],"7":[3],"8":[1],"9":[2],"20":[1],"21":[2],"22":[3],"23":[1],"24":[2],"25":[3],"26":[1],"27":[2],"28":[3],"29":[1],"30":[2],"31":[3],"32":[1],"33":[2],"34":[3],"35":[1],"36":[2],"37":[3],"38":[1],"39":[2],"40":[3],"41":[1],"42":[2],"43":[3]},"topic_id":"RGxJyefAQlKrmY3LTVbKGw","adding_replicas":{},"removing_replicas":{},"version":3}
