Kafka CLI tools overview - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of the kafka-topics.sh command?

You run the command kafka-topics.sh --list --bootstrap-server localhost:9092 on a Kafka cluster with three topics: orders, payments, and shipments. What will be the output?

Kafka

kafka-topics.sh --list --bootstrap-server localhost:9092

A Error: Topic list not found

B

orders
payments
shipments

C

Topic orders created
Topic payments created
Topic shipments created

D No topics found

💡 Hint

The --list option shows all existing topics in the cluster.

The kafka-topics.sh tool with --list option lists all topics currently in the Kafka cluster. Since there are three topics, their names are printed line by line.

❓ Predict Output

intermediate

What does kafka-console-producer.sh output after sending a message?

You run kafka-console-producer.sh --broker-list localhost:9092 --topic test and type the message Hello Kafka. What output do you see immediately after pressing Enter?

Kafka

kafka-console-producer.sh --broker-list localhost:9092 --topic test

A Error: Unable to send message

B Hello Kafka

C (No output, just a new prompt line)

D Message sent successfully

💡 Hint

The console producer does not print confirmation messages after sending.

The kafka-console-producer.sh tool sends messages to Kafka but does not print any confirmation or echo the message. It just waits for the next input.

❓ Predict Output

advanced

What is the output of kafka-consumer-groups.sh --describe?

You run kafka-consumer-groups.sh --bootstrap-server localhost:9092 --group my-group --describe and the group has one member consuming from topic orders partition 0 with lag 5. What output do you expect?

Kafka

kafka-consumer-groups.sh --bootstrap-server localhost:9092 --group my-group --describe

A GROUP my-group has no lag

B Error: Group my-group not found

C No consumers found for group my-group

D

GROUP       TOPIC   PARTITION  CURRENT-OFFSET  LOG-END-OFFSET  LAG  CONSUMER-ID  HOST  CLIENT-ID
my-group    orders  0          100             105             5    consumer-1   /127.0.0.1  client-1

💡 Hint

The --describe option shows detailed info including lag.

The kafka-consumer-groups.sh tool with --describe prints a table with group, topic, partition, offsets, lag, and consumer details. Since lag is 5, it is shown in the output.

❓ Predict Output

advanced

What error does kafka-configs.sh produce with invalid syntax?

You run kafka-configs.sh --alter --entity-type topics --entity-name my-topic --add-config retention.ms=abc --bootstrap-server localhost:9092. What error will you see?

Kafka

kafka-configs.sh --alter --entity-type topics --entity-name my-topic --add-config retention.ms=abc --bootstrap-server localhost:9092

A Error: Invalid value for retention.ms: abc

B Configuration updated successfully

C Error: Unknown entity type topics

D Syntax error: missing equals sign

💡 Hint

retention.ms expects a number in milliseconds.

The kafka-configs.sh tool validates config values. Since retention.ms expects a numeric value, passing 'abc' causes an invalid value error.

🧠 Conceptual

expert

Which Kafka CLI tool is used to reset consumer group offsets?

You want to move the offsets of a consumer group backward to reprocess messages. Which Kafka CLI tool and option do you use?

A kafka-consumer-groups.sh with --reset-offsets

B kafka-topics.sh with --alter-offsets

C kafka-configs.sh with --reset-consumer

D kafka-console-consumer.sh with --rewind

💡 Hint

Resetting offsets is done via the consumer groups tool.

The kafka-consumer-groups.sh tool supports the --reset-offsets option to change offsets for a consumer group to a specific point.