Why topics organize messages in Kafka - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a Kafka topic named 'orders'.

Kafka

bin/kafka-topics.sh --create --topic [1] --bootstrap-server localhost:9092

Drag options to blanks, or click blank then click option'

Aevents

Bmessages

Corders

Dlogs

Attempts:

3 left

💡 Hint

Common Mistakes

Using a generic name like 'messages' instead of a specific topic name.

Leaving the topic name blank.

The topic name 'orders' is used to organize messages related to orders in Kafka.

2fill in blank

medium

Complete the code to produce a message to the 'orders' topic.

Kafka

echo 'order_id=123' | bin/kafka-console-producer.sh --topic [1] --bootstrap-server localhost:9092

Drag options to blanks, or click blank then click option'

Aorders

Blogs

Cmessages

Devents

Attempts:

3 left

💡 Hint

Common Mistakes

Sending messages to the wrong topic name.

Typos in the topic name.

The message is sent to the 'orders' topic to keep order-related messages organized.

3fill in blank

hard

Fix the error in the command to consume messages from the 'orders' topic.

Kafka

bin/kafka-console-consumer.sh --topic [1] --bootstrap-server localhost:9092 --from-beginning

Drag options to blanks, or click blank then click option'

Aorders

Bmessages

Clogs

Devents

Attempts:

3 left

💡 Hint

Common Mistakes

Using a topic name that does not exist.

Misspelling the topic name.

Consuming from the correct topic 'orders' ensures you get the right messages.

4fill in blank

hard

Fill both blanks to create a topic with 3 partitions and a replication factor of 2.

Kafka

bin/kafka-topics.sh --create --topic orders --partitions [1] --replication-factor [2] --bootstrap-server localhost:9092

Drag options to blanks, or click blank then click option'

A3

B1

C2

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Setting replication factor higher than the number of brokers.

Using zero or negative numbers.

Partitions divide the topic for parallelism; replication factor ensures fault tolerance.

5fill in blank

hard

Fill all three blanks to produce a message with key 'user1' and value 'login' to the 'user-events' topic.

Kafka

echo '[1]:[2]' | bin/kafka-console-producer.sh --topic [3] --property parse.key=true --property key.separator=: --bootstrap-server localhost:9092

Drag options to blanks, or click blank then click option'

Auser1

Blogin

Cuser-events

Dlogout

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up key and value positions.

Using the wrong topic name.

The key 'user1' and value 'login' are sent to the 'user-events' topic to organize user activity messages.

Practice

1. Why does Kafka use topics to organize messages?

easy

A. To group related messages together for easier management

B. To store messages permanently on the producer side

C. To encrypt messages automatically

D. To limit the number of messages sent

Solution

1. Step 1: Understand the purpose of topics in Kafka

   Topics are used to group messages that belong to the same category or stream.

2. Step 2: Identify the role of topics in message management

   Grouping messages helps producers and consumers handle data efficiently and logically.

3. Final Answer:

   To group related messages together for easier management -> Option A

4. Quick Check:

   Topics group messages = A [OK]

Hint: Topics group messages logically for easy handling [OK]

Common Mistakes:

• Thinking topics store messages on producer side
• Confusing topics with encryption features
• Believing topics limit message quantity

2. Which of the following is the correct way to create a topic in Kafka using the command line?

easy

A. kafka topic create myTopic --partitions 3

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

C. create kafka topic myTopic partitions=3

D. kafka-create-topic --name myTopic --partitions 3

Solution

1. Step 1: Recall the Kafka CLI syntax for topic creation

   The correct command uses 'kafka-topics' with '--create' and required flags.

2. Step 2: Match the command with the correct options

   kafka-topics --create --topic myTopic --partitions 3 --replication-factor 1 --bootstrap-server localhost:9092 matches the official syntax including bootstrap-server, partitions, and replication-factor.

3. Final Answer:

   kafka-topics --create --topic myTopic --partitions 3 --replication-factor 1 --bootstrap-server localhost:9092 -> Option B

4. Quick Check:

   Correct Kafka topic creation syntax = D [OK]

Hint: Use kafka-topics with --create and required flags [OK]

Common Mistakes:

• Using incorrect command names like kafka-create-topic
• Omitting bootstrap-server flag
• Wrong order or missing required flags

3. Given a Kafka topic with 3 partitions, what happens when a producer sends 6 messages without specifying a key?

medium

A. Messages are sent randomly to any partition

B. All messages go to the first partition

C. Messages are distributed evenly across the 3 partitions

D. Messages are rejected because no key is provided

Solution

1. Step 1: Understand default partitioning behavior without a key

   When no key is provided, Kafka uses round-robin to distribute messages evenly across partitions.

2. Step 2: Apply this to 6 messages and 3 partitions

   Messages will be sent 2 per partition, balancing the load.

3. Final Answer:

   Messages are distributed evenly across the 3 partitions -> Option C

4. Quick Check:

   No key means round-robin distribution = A [OK]

Hint: No key means even round-robin distribution [OK]

Common Mistakes:

• Assuming all messages go to one partition
• Thinking messages are rejected without a key
• Believing distribution is random without pattern

4. You have a Kafka topic with 2 partitions but your consumer only reads from partition 0. What is the likely problem?

medium

A. Kafka does not support multiple partitions

B. The topic only has one partition

C. The producer is sending messages only to partition 1

D. The consumer is not configured to subscribe to all partitions

Solution

1. Step 1: Analyze consumer subscription behavior

   If a consumer reads only from partition 0, it likely subscribed only to that partition explicitly.

2. Step 2: Check topic partition count and producer behavior

   The topic has 2 partitions, so consumer should subscribe to both to read all messages.

3. Final Answer:

   The consumer is not configured to subscribe to all partitions -> Option D

4. Quick Check:

   Consumer subscription controls partitions read = C [OK]

Hint: Consumer must subscribe to all partitions to read all messages [OK]

Common Mistakes:

• Assuming topic has only one partition
• Believing Kafka does not support multiple partitions
• Thinking producer controls consumer reading partitions

5. How can partitioning in Kafka topics improve performance when handling large message streams?

hard

A. By allowing parallel processing of messages across multiple consumers

B. By encrypting messages faster

C. By reducing the total number of messages sent

D. By storing messages only on the producer side

Solution

1. Step 1: Understand the role of partitions in Kafka topics

   Partitions split a topic into multiple parts that can be processed independently.

2. Step 2: Connect partitions to performance benefits

   Multiple consumers can read from different partitions in parallel, increasing throughput and speed.

3. Final Answer:

   By allowing parallel processing of messages across multiple consumers -> Option A

4. Quick Check:

   Partitions enable parallelism = B [OK]

Hint: Partitions enable parallel consumer processing [OK]

Common Mistakes:

• Confusing partitioning with encryption
• Thinking partitioning reduces message count
• Believing messages are stored only on producer