|NO.Z.00041|——————————|^^ 创建 ^^|——|Hadoop&kafka.V26|——|kafka.v26|主题管理.v01|

一、主题管理：创建主题

### --- 方案一：创建主题

~~~     # 创建主题
[root@hadoop ~]#  kafka-topics.sh --zookeeper localhost:2181/myKafka --create --topic topic_x \
--partitions 3 --replication-factor 1

### --- 查看创建的主题

[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --list
topic_x
[root@hadoop ~]# ls /opt/yanqi/servers/kafka/kafka-logs/ | grep topic_x
topic_x-0
topic_x-1
topic_x-2
[root@hadoop ~]# ls /opt/yanqi/servers/kafka/kafka-logs/topic_x-0/ 
00000000000000000000.index  00000000000000000000.log  00000000000000000000.timeindex  leader-epoch-checkpoint

### --- 在zookeeper下会有创建的记录
~~~     创建主题会和zookeeper进行交互

[zk: localhost:2181(CONNECTED) 1] get /myKafka/config/topics/topic_x
{"version":1,"config":{}}
cZxid = 0x4fb
ctime = Wed Sep 22 21:15:15 CST 2021
mZxid = 0x4fb
mtime = Wed Sep 22 21:15:15 CST 2021
pZxid = 0x4fb
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 25
numChildren = 0

### --- 方案二：创建主题
~~~     cleanup.policy：清理
~~~     compact：压缩存储

[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --create --topic \
topic_y --partitions 2 --replication-factor 1 --config cleanup.policy=compact

~~~     # 查看创建的主题

[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --list
topic_x
topic_y 
 
[root@hadoop ~]# ls /opt/yanqi/servers/kafka/kafka-logs/ | grep topic_y
topic_y-0
topic_y-1

[root@hadoop ~]# ls /opt/yanqi/servers/kafka/kafka-logs/topic_y-0/
00000000000000000000.index  00000000000000000000.log  00000000000000000000.timeindex  leader-epoch-checkpoint

~~~     # 在zookeeper下会有创建的记录

[zk: localhost:2181(CONNECTED) 2] get /myKafka/config/topics/topic_x
{"version":1,"config":{}}
cZxid = 0x4fb
ctime = Wed Sep 22 21:15:15 CST 2021
mZxid = 0x4fb
mtime = Wed Sep 22 21:15:15 CST 2021
pZxid = 0x4fb
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 25
numChildren = 0

### --- 方案三：创建主题
~~~     --config compression.type：指定压缩格式为gzip
~~~     --config max.message.bytes：指定压缩的大小

[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --create --topic \
> topic_z --partitions 5 --replication-factor 1 \
> --config compression.type=gzip --config max.message.bytes=512

~~~     # 查看创建的主题

[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --list
__consumer_offsets
topic_x
topic_y
topic_z
tp_demo_01
[root@hadoop ~]# ls /opt/yanqi/servers/kafka/kafka-logs/ | grep topic_z
topic_z-0
topic_z-1
topic_z-2
topic_z-3
topic_z-4
[root@hadoop ~]# ls /opt/yanqi/servers/kafka/kafka-logs/topic_z-0/
00000000000000000000.index  00000000000000000000.log  00000000000000000000.timeindex  leader-epoch-checkpoint

~~~     # 在zookeeper下会有创建的记录

[zk: localhost:2181(CONNECTED) 0] get /myKafka/config/topics/topic_z
{"version":1,"config":{"max.message.bytes":"512","compression.type":"gzip"}}
cZxid = 0x51f
ctime = Wed Sep 22 21:37:24 CST 2021
mZxid = 0x51f
mtime = Wed Sep 22 21:37:24 CST 2021
pZxid = 0x51f
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 76
numChildren = 0

二、查看主题

### --- 查看主题
~~~     # 列出所有可用的主题

[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --list
__consumer_offsets
topic_x
topic_y
topic_z

### --- 查看某一个主题的详细信息
~~~     Topic:topic_x                     主题名称
~~~     PartitionCount:3                  主题有多少个分区
~~~     ReplicationFactor:1               主题有多少个副本
~~~     Partition: 3                      分区编号  
~~~     Leader: 0                         分区的首领子那个broker上，在0号broker上，因为现在只有一个节点
~~~     Replicas: 0                       副本在0号broker上
~~~     Isr: 0                            同一个副本，在0号分区上

[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --describe --topic topic_x
Topic:topic_x   PartitionCount:3    ReplicationFactor:1 Configs:
    Topic: topic_x  Partition: 0    Leader: 0   Replicas: 0 Isr: 0
    Topic: topic_x  Partition: 1    Leader: 0   Replicas: 0 Isr: 0
    Topic: topic_x  Partition: 2    Leader: 0   Replicas: 0 Isr: 0

### --- 查看覆盖过默认设置的主题

[root@hadoop ~]# kafka-topics.sh --zookeeper localhost:2181/myKafka --topics-with-overrides --describe
Topic:__consumer_offsets    PartitionCount:50   ReplicationFactor:1 Configs:segment.bytes=104857600,cleanup.policy=compact,compression.type=producer
Topic:topic_y   PartitionCount:2    ReplicationFactor:1 Configs:cleanup.policy=compact
Topic:topic_z   PartitionCount:5    ReplicationFactor:1 Configs:compression.type=gzip,max.message.bytes=512

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Walter Savage Landor:strove with none,for none was worth my strife.Nature I loved and, next to Nature, Art:I warm'd both hands before the fire of life.It sinks, and I am ready to depart

                                                                                                                                                   ——W.S.Landor

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