Kafka CLI Basics

Introduction

What is Kafka CLI Basics? Kafka CLI tools create topics, inspect groups, produce test records, consume streams, and debug metadata.

Understanding the topic

What happens — Kafka CLI Basics:

• kafka-topics: create and describe topics.
• kafka-console-producer/consumer: quick tests.
• kafka-consumer-groups: inspect lag.
• Use CLI to debug before changing code.

Visual explanation

Pipeline view:

Input topic
  ↓
filter/map/join/window
  ↓
state store + changelog
  ↓
output topic

Step-by-step explanation

1. Create topic — partitions + RF.
2. Produce test — console producer.
3. Consume — from-beginning.
4. Inspect group — --describe lag.

Informative example

Example:

kafka-topics --bootstrap-server localhost:9092 --create --topic payments --partitions 6 --replication-factor 3
kafka-console-producer --bootstrap-server localhost:9092 --topic payments
kafka-console-consumer --bootstrap-server localhost:9092 --topic payments --from-beginning
kafka-consumer-groups --bootstrap-server localhost:9092 --describe --group payments-service

Execution workflow

Best practices

• Choose keys before joins and aggregations.
• Name internal topics and state stores clearly.
• Test topology with realistic ordering and late events.
• Monitor processing latency, commit rate, and restore time.

Common mistakes

• Unexpected repartition topics from wrong key choices.
• Ignoring late-arriving events in windows.
• Underestimating state-store disk and restore time.

Summary

Kafka CLI Basics — Design topology around keys, state stores, window boundaries, changelog topics, and exactly-once needs.