Kafka主题与Zookeeper相关吗，如果Zookeeper更改，该主题将消失

Question

I was working with Kafka . I downloaded the zookeeper , extracted and started it. Then I downloaded Kafka , extracted the zipped file and started Kafka . Everything was working good. I created few topics and I was able to send and receive messages. After that I stopped Kafka and Zookeeper . Then I read that Kafka itself provides Zookeeper . So I started Zookeeper that was provided with Kafka . However the data directory for it was different, and then I started Kafka from same configuration file and same data directory location. However after starting Kafka I could not find the topics that I had created.

I just want to know that, does this mean the meta data about the topics is maintained by Zookeeper . I searched Kafka documentation, however, I could not find anything in detail. https://kafka.apache.org/documentation/

Answer 1

Check this documentation provided by confluent. According to this Apache Kafka® uses ZooKeeper to store persistent cluster metadata and is a critical component of the Confluent Platform deployment. For example, if you lost the Kafka data in ZooKeeper, the mapping of replicas to Brokers and topic configurations would be lost as well, making your Kafka cluster no longer functional and potentially resulting in total data loss. Apache Kafka® uses ZooKeeper to store persistent cluster metadata and is a critical component of the Confluent Platform deployment. For example, if you lost the Kafka data in ZooKeeper, the mapping of replicas to Brokers and topic configurations would be lost as well, making your Kafka cluster no longer functional and potentially resulting in total data loss.

So, the answer to your question is, yes, the purpose of zookeeper is to store relevant metadata about the kafka brokers, topics, etc,.

Also, since you have just started working on Kafka and Zookeeper, I would like to mention this. By default, Kafka stored it's data in a temp location which get's deleted on system reboot, so you should change that as well.

Answer 2

the answer to your question tag is yes,

1)Initially you started standalone zookeeper from zip file and you stopped the zookeeper, which means the topics that are created are stored in the zookeeper standalone are lost.Now you persistent cluster metadata related to Kafka is lost .

2)second time you started the zookeeper from the package that comes along with Kafka, now the new zookeeper instance does not have any topics information that you created previously, so you need to create newly .

3) suppose in case 1: if you close the terminal and start again the zookeeper from standalone , you no need to create the Topic again ,but if you stopped the zookeeper server from standalone then topics are lost.

in simple : you created two separate zookeeper instances, where topics will not be shared between them .