kafka和zookeeper的关系

zookeeper主要负责协调管理并保存 Kafka 集群的所有元数据信息，比如集群都有哪些 Broker 在运行、创建了哪些 Topic，每个 Topic 都有多少分区以及这些分区的 Leader 副本都在哪些机器上等信息。

如下：
[cluster, controller_epoch, controller, brokers, zookeeper, admin, isr_change_notification, consumers, latest_producer_id_block, config]

其中，除了zookeeper，其余节点都和kafka有关

brokers 存放创建的主题和broker的id

如下：
[zk: localhost:2181(CONNECTED) 28] ls /brokers
[ids, topics, seqid]

topic 存放Controller的信息 controller_epoch:controller选举次数 leader_epoch：leader副本选举次数
[zk: localhost:2181(CONNECTED) 20] get /brokers/topics/t1/partitions/1/state

[zk: localhost:2181(CONNECTED) 21] get /brokers/topics/t1/partitions/0/state

[zk: localhost:2181(CONNECTED) 29] ls /brokers/ids
[1, 2, 3]

[zk: localhost:2181(CONNECTED) 30] ls /brokers/topics
[t1]

其中，Kafka存放id的文件是：/opt/module/kafka-2.11/datas/meta.properties
内容：broker.id=1

controller 存放的是kafka集群的master
如下：
[zk: localhost:2181(CONNECTED) 8] get /controller

{"version":1,"brokerid":1,"timestamp":"1606979310534"}
cZxid = 0x50000006e
ctime = Thu Dec 03 15:08:30 CST 2020
mZxid = 0x50000006e
mtime = Thu Dec 03 15:08:30 CST 2020
pZxid = 0x50000006e
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x100009e9e9a0007
dataLength = 54
numChildren = 0

consumers 存放消费者组的相关信息
如下：
[zk: localhost:2181(CONNECTED) 22] ls /consumers
[console-consumer-37119] --> 消费者组

[zk: localhost:2181(CONNECTED) 24] ls /consumers/console-consumer-37119
[ids, owners, offsets]

[zk: localhost:2181(CONNECTED) 25] ls /consumers/console-consumer-37119/offsets
[t1] --> 主题

[zk: localhost:2181(CONNECTED) 26] ls /consumers/console-consumer-37119/offsets/t1
[0, 1] --> 分区

[zk: localhost:2181(CONNECTED) 27] get /consumers/console-consumer-37119/offsets/t1/0
40 --> 消费者偏移量
cZxid = 0x500000047
ctime = Thu Dec 03 14:18:52 CST 2020
mZxid = 0x500000078
mtime = Thu Dec 03 16:10:51 CST 2020
pZxid = 0x500000047
cversion = 0
dataVersion = 9
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 2
numChildren = 0

如果要格式化zookeeper和kafka:

删除kafka的logs文件
删除zookeeper的：/opt/module/zookeeper-3.4.14/zkData/version-2 文件