All the information about Kafka Topics is stored in Zookeeper (Cluster Manager). For each Topic, you may specify the replication factor and the number of partitions. A topic is identified by its name. All these information has to be provided as arguments to the shell script, /kafka-topics.sh, while creating a new Kafka Topic.
Following is the syntax to create a topic :
./kafka-topics.sh --create --zookeeper <ZOOKEEPER_URL:PORT> --replication-factor <NO_OF_REPLICATIONS> --partitions <NO_OF_PARTITIONS> --topic <TOPIC_NAME>
where the arguments are :
|<ZOOKEEPER_URL:PORT>||IP and port at which zookeeper is running.|
|<NO_OF_REPLICATIONS>||Number of replications that the topic has to maintain in the Kafka Cluster.|
|<NO_OF_PARTITIONS>||Number of partitions into which the Topic has to be partitioned.|
|<TOPIC_NAME>||Name of the Kafka Topic to be created.|
To create a topic in Apache Kafka, Zookeeper and Kafka have to be up and running.
Navigate to the root of Kafka directory and run each of the following commands in separate terminals to start Zookeeper and Kafka Cluster.
$ bin/zookeeper-server-start.sh config/zookeeper.properties
$ bin/kafka-server-start.sh config/server.properties
Kafka provides a script, kafka-topics.sh, in the <KAFKA_HOME>/bin/ directory, to create a topic in the Kafka cluster.
An example is given below :
./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic sampleTopic
Running the script creates a Topic named sampleTopic with 1 replication and 1 partition maintaining metadata in the Zookeeper live at localhost:2181.
Open a terminal from bin directory and run the shell script kafka-topics.sh as shown below :
Created topic “sampleTopic”. : sampleTopic has been created.
When you try to create a duplicate topic, you could get an error saying the topic already exists. An example is given below :
In this Apache Kafka Tutorial – Kafka Create Topic, we have successfully created a Topic in the Kafka cluster.