How to Create Topic in Kafka: Simple Steps and Examples

To create a topic in Kafka, use the kafka-topics.sh command with the --create option, specifying the topic name, number of partitions, and replication factor. For example, kafka-topics.sh --create --topic my-topic --bootstrap-server localhost:9092 --partitions 3 --replication-factor 1 creates a topic named my-topic with 3 partitions and replication factor 1.

Syntax

The basic syntax to create a Kafka topic is:

• kafka-topics.sh: The Kafka command line tool to manage topics.
• --create: Flag to create a new topic.
• --topic <topic-name>: Name of the topic to create.
• --bootstrap-server <host:port>: Kafka broker address to connect.
• --partitions <number>: Number of partitions for the topic.
• --replication-factor <number>: Number of replicas for fault tolerance.

bash

kafka-topics.sh --create --topic <topic-name> --bootstrap-server <host:port> --partitions <num> --replication-factor <num>

Example

This example creates a topic named my-topic with 3 partitions and a replication factor of 1 on a Kafka broker running locally.

bash

kafka-topics.sh --create --topic my-topic --bootstrap-server localhost:9092 --partitions 3 --replication-factor 1

Output

Created topic "my-topic".

Common Pitfalls

Common mistakes when creating Kafka topics include:

• Not specifying the --bootstrap-server or using the wrong broker address.
• Setting a replication factor higher than the number of available brokers, which causes errors.
• Using an existing topic name without realizing it, which will not create a new topic.
• Forgetting to specify partitions, which defaults to 1 but may not suit your needs.

Always check your Kafka cluster status and broker count before setting replication factor.

bash

## Wrong: replication factor higher than brokers
kafka-topics.sh --create --topic test-topic --bootstrap-server localhost:9092 --partitions 2 --replication-factor 3

## Right: replication factor not exceeding brokers
kafka-topics.sh --create --topic test-topic --bootstrap-server localhost:9092 --partitions 2 --replication-factor 1

Output

Error: Replication factor: 3 larger than available brokers: 1
Created topic "test-topic".

Quick Reference

Option	Description
--create	Create a new topic
--topic	Name of the topic
--bootstrap-server	Kafka broker address
--partitions	Number of partitions
--replication-factor	Number of replicas for fault tolerance

Key Takeaways

Use kafka-topics.sh with --create and specify topic name, partitions, and replication factor.

Ensure replication factor does not exceed the number of Kafka brokers available.

Always provide the correct --bootstrap-server address to connect to your Kafka cluster.

Check if the topic already exists before creating to avoid conflicts.

Partitions control parallelism; replication factor controls fault tolerance.