Acknowledgment modes (acks=0, 1, all) in Kafka - Mini Project: Build & Apply

Understanding Kafka Acknowledgment Modes (acks=0, 1, all)

📖 Scenario: You are working with Apache Kafka to send messages to a topic. Kafka allows you to control how it confirms message delivery using acknowledgment modes called acks. These modes help balance speed and reliability.In this project, you will create simple Kafka producer configurations to see how acks=0, acks=1, and acks=all work.

🎯 Goal: You will write Kafka producer configuration code snippets for each acknowledgment mode and print a message showing which mode is set. This will help you understand how to configure Kafka producers for different delivery guarantees.

📋 What You'll Learn

Create a Kafka producer configuration dictionary with acks set to 0

Create a variable called topic with the value 'test-topic'

Create a Kafka producer configuration dictionary with acks set to 1

Create a Kafka producer configuration dictionary with acks set to 'all'

Print the acks value from each configuration with a descriptive message

💡 Why This Matters

🌍 Real World

Kafka is widely used for building real-time data pipelines and streaming apps. Understanding acknowledgment modes helps ensure messages are delivered reliably or quickly depending on the need.

💼 Career

Kafka producer configuration is a key skill for backend developers, data engineers, and anyone working with event-driven systems or streaming data.

1

Create Kafka producer config with acks=0

Create a dictionary called producer_config_acks0 with the key 'acks' set to 0.

Kafka

# Create the producer_config_acks0 dictionary with 'acks' set to 0
# Your code here

Hint

The acks key controls the acknowledgment mode. Setting it to 0 means no acknowledgment is required.

2

Create a topic variable

Create a variable called topic and set it to the string 'test-topic'.

Kafka

producer_config_acks0 = {'acks': 0}
# Create the topic variable with value 'test-topic'
# Your code here

Hint

The topic variable holds the name of the Kafka topic where messages will be sent.

3

Create Kafka producer config with acks=1

Create a dictionary called producer_config_acks1 with the key 'acks' set to 1.

Kafka

producer_config_acks0 = {'acks': 0}
topic = 'test-topic'
# Create the producer_config_acks1 dictionary with 'acks' set to 1
# Your code here

Hint

Setting acks to 1 means the leader broker will acknowledge the write.

4

Create Kafka producer config with acks='all' and print all configs

Create a dictionary called producer_config_acks_all with the key 'acks' set to the string 'all'. Then print the acks value from producer_config_acks0, producer_config_acks1, and producer_config_acks_all with messages exactly as shown below:
"acks=0 mode: 0"
"acks=1 mode: 1"
"acks=all mode: all"

Kafka

producer_config_acks0 = {'acks': 0}
topic = 'test-topic'
producer_config_acks1 = {'acks': 1}
# Create producer_config_acks_all with 'acks' set to 'all'
# Print the acks values from all three configs with the exact messages
# Your code here

Hint

Use f-strings to print the acks values with the exact messages.

Practice

1. Which acks mode in Kafka provides the fastest message sending but with the least safety?

easy

A. acks=0

B. acks=1

C. acks=all

D. None of the above

Solution

1. Step 1: Understand acks=0 behavior

   This mode means the producer does not wait for any acknowledgment from the broker, so it sends messages fastest but with no guarantee of delivery.

2. Step 2: Compare with other modes

   acks=1 waits for leader confirmation, and acks=all waits for all replicas, both slower but safer.

3. Final Answer:

   acks=0 -> Option A

4. Quick Check:

   Fastest but least safe = acks=0 [OK]

Hint: No wait for confirmation means fastest mode is acks=0 [OK]

Common Mistakes:

• Confusing acks=0 with acks=1
• Thinking acks=all is fastest
• Assuming acks=0 waits for leader

2. Which of the following is the correct way to set the acknowledgment mode to wait for all replicas in Kafka producer configuration?

easy

A. "acks=1"

B. "acks=0"

C. "acks=all"

D. "ack=all"

Solution

1. Step 1: Recall correct property name and value

   The property is acks (plural), and to wait for all replicas, the value is all.

2. Step 2: Check options for syntax correctness

   "acks=all" uses correct key and value: "acks=all". "ack=all" has a typo "ack" instead of "acks".

3. Final Answer:

   "acks=all" -> Option C

4. Quick Check:

   Wait for all replicas = acks=all [OK]

Hint: Remember plural 'acks' and value 'all' for all replicas [OK]

Common Mistakes:

• Using 'ack' instead of 'acks'
• Confusing 'acks=1' with 'acks=all'
• Setting 'acks=0' for all replicas

3. Consider this Kafka producer code snippet:

props.put("acks", "1");
producer.send(record);
System.out.println("Message sent");

What does acks=1 guarantee before printing "Message sent"?

medium

A. Message is stored only in producer buffer

B. No guarantee; message may be lost

C. All replicas have confirmed the message

D. Leader broker has confirmed the message

Solution

1. Step 1: Understand acks=1 meaning

   This mode waits for the leader broker to confirm the message is received and written to its log.

2. Step 2: Compare with other options

   acks=0 gives no guarantee, acks=all waits for all replicas, and producer buffer storage is unrelated.

3. Final Answer:

   Leader broker has confirmed the message -> Option D

4. Quick Check:

   acks=1 means leader confirmation [OK]

Hint: acks=1 waits for leader confirmation only [OK]

Common Mistakes:

• Thinking acks=1 waits for all replicas
• Assuming no guarantee with acks=1
• Confusing producer buffer with broker confirmation

4. You have this Kafka producer configuration:

props.put("acks", "alll");

What is the problem with this configuration?

medium

A. Typo in the value; should be "all"

B. Typo in the key; should be "ack"

C. No problem; "alll" is valid

D. Should be an integer, not a string

Solution

1. Step 1: Check the value spelling

   The correct value for waiting all replicas is "all", but here it is misspelled as "alll" with an extra 'l'.

2. Step 2: Verify key and value types

   The key "acks" is correct and the value should be a string. So the problem is only the typo in the value.

3. Final Answer:

   Typo in the value; should be "all" -> Option A

4. Quick Check:

   Value must be "all", not "alll" [OK]

Hint: Check spelling of 'all' carefully in acks value [OK]

Common Mistakes:

• Assuming 'alll' is valid
• Changing key to 'ack' instead of 'acks'
• Using integer instead of string for acks

5. You want to ensure maximum data safety in Kafka producer but can tolerate some delay. Which acks setting should you use and why?

hard

A. acks=1 because leader confirmation is enough

B. acks=all because it waits for all replicas

C. acks=0 because it is fastest

D. acks=-1 because it disables acknowledgments

Solution

1. Step 1: Identify safety vs speed tradeoff

   acks=all waits for all replicas to confirm, ensuring maximum data safety but slower performance.

2. Step 2: Evaluate other options

   acks=0 is fastest but unsafe, acks=1 waits only for leader, and acks=-1 is invalid or equivalent to acks=all but less clear.

3. Final Answer:

   acks=all because it waits for all replicas -> Option B

4. Quick Check:

   Max safety = acks=all [OK]

Hint: Max safety means waiting for all replicas: acks=all [OK]

Common Mistakes:

• Choosing acks=0 for safety
• Confusing acks=-1 as disabling acknowledgments
• Thinking leader confirmation is max safety