ACL-based authorization in Kafka - Mini Project: Build & Apply

ACL-based Authorization in Kafka

📖 Scenario: You are setting up a Kafka cluster where different users have specific permissions to access topics. To keep the data safe, you will create Access Control Lists (ACLs) that allow or deny users certain actions on Kafka topics.

🎯 Goal: Build a simple Kafka ACL configuration that grants a user permission to read from a topic and denies another user from writing to the same topic.

📋 What You'll Learn

Create a Kafka topic named orders

Create an ACL that allows user alice to read from the orders topic

Create an ACL that denies user bob from writing to the orders topic

Verify the ACLs by listing them

💡 Why This Matters

🌍 Real World

Kafka ACLs help secure data streams by controlling who can read or write to topics, protecting sensitive information.

💼 Career

Understanding Kafka ACLs is important for roles like DevOps engineers, Kafka administrators, and backend developers working with secure data pipelines.

1

Create the Kafka topic orders

Use the Kafka CLI command to create a topic named orders with 1 partition and a replication factor of 1.

Kafka

# Use kafka-topics.sh to create the topic 'orders'
# Your code here

Hint

Use kafka-topics.sh --create with the right options to create the topic.

2

Create an ACL to allow user alice to read from orders

Use the Kafka CLI command to add an ACL that allows the user alice to perform the READ operation on the orders topic.

Kafka

kafka-topics.sh --create --topic orders --partitions 1 --replication-factor 1 --bootstrap-server localhost:9092
# Add ACL to allow alice to READ from orders
# Your code here

Hint

Use kafka-acls.sh --add with --allow-principal User:alice and --operation READ.

3

Create an ACL to deny user bob from writing to orders

Use the Kafka CLI command to add an ACL that denies the user bob the WRITE operation on the orders topic.

Kafka

kafka-topics.sh --create --topic orders --partitions 1 --replication-factor 1 --bootstrap-server localhost:9092
kafka-acls.sh --add --allow-principal User:alice --operation READ --topic orders --bootstrap-server localhost:9092
# Add ACL to deny bob WRITE access to orders
# Your code here

Hint

Use kafka-acls.sh --add --deny-principal User:bob with --operation WRITE.

4

List all ACLs for the orders topic

Use the Kafka CLI command to list all ACLs for the orders topic to verify the permissions.

Kafka

kafka-topics.sh --create --topic orders --partitions 1 --replication-factor 1 --bootstrap-server localhost:9092
kafka-acls.sh --add --allow-principal User:alice --operation READ --topic orders --bootstrap-server localhost:9092
kafka-acls.sh --add --deny-principal User:bob --operation WRITE --topic orders --bootstrap-server localhost:9092
# List ACLs for topic orders
# Your code here

Hint

Use kafka-acls.sh --list --topic orders to see the ACLs.

Practice

1. What is the main purpose of ACL-based authorization in Kafka?

easy

A. To control who can access Kafka topics and perform operations

B. To speed up message processing in Kafka

C. To store messages in a compressed format

D. To monitor Kafka cluster health

Solution

1. Step 1: Understand ACL-based authorization

   ACL-based authorization is used to manage permissions for users or clients in Kafka.

2. Step 2: Identify its main role

   Its main role is to control access to Kafka topics and operations, ensuring security.

3. Final Answer:

   To control who can access Kafka topics and perform operations -> Option A

4. Quick Check:

   ACL controls access = B [OK]

Hint: ACL means controlling access rights in Kafka [OK]

Common Mistakes:

• Confusing ACL with performance tuning
• Thinking ACL compresses data
• Assuming ACL monitors cluster health

2. Which of the following is the correct command to add an ACL for a user named alice to read from topic orders?

easy

A. kafka-acls --add --allow-principal User:alice --operation Read --topic orders

B. kafka-acls --remove --allow-principal User:alice --operation Read --topic orders

C. kafka-acls --add --deny-principal User:alice --operation Write --topic orders

D. kafka-acls --add --allow-principal User:bob --operation Read --topic orders

Solution

1. Step 1: Identify the command to add ACL

   The command to add an ACL uses --add and specifies the principal and operation.

2. Step 2: Match user, operation, and topic

   We want to add read permission for user alice on topic orders, so the command must include these exactly.

3. Final Answer:

   kafka-acls --add --allow-principal User:alice --operation Read --topic orders -> Option A

4. Quick Check:

   Add ACL for alice to read orders = D [OK]

Hint: Add ACL uses --add and --allow-principal [OK]

Common Mistakes:

• Using --remove instead of --add
• Using deny instead of allow
• Specifying wrong user or operation

3. Given the following ACLs:

kafka-acls --add --allow-principal User:bob --operation Write --topic payments
kafka-acls --add --allow-principal User:bob --operation Read --topic payments

What will happen if user bob tries to consume messages from topic payments?

medium

A. Bob can only produce messages but not consume

B. Bob will get a permission denied error when consuming messages

C. Bob can neither produce nor consume messages

D. Bob will be able to consume messages from the payments topic

Solution

1. Step 1: Analyze the ACLs for user bob

   Bob has both Write and Read permissions on the payments topic.

2. Step 2: Understand consuming messages requires Read permission

   Since Bob has Read permission, he can consume messages from the payments topic.

3. Final Answer:

   Bob will be able to consume messages from the payments topic -> Option D

4. Quick Check:

   Read permission allows consume = C [OK]

Hint: Read permission lets user consume messages [OK]

Common Mistakes:

• Assuming Write permission alone allows consuming
• Confusing produce and consume permissions
• Ignoring the Read permission present

4. You run the command:

kafka-acls --add --allow-principal User:carol --operation Read --topic sales

But Carol still cannot read from the sales topic. What is the most likely cause?

medium

A. The ACL was added but the Kafka broker was not restarted

B. Carol needs Write permission to read messages

C. Carol's client is not authenticating as User:carol

D. The ACL was added for the wrong user

Solution

1. Step 1: Check if ACL command syntax is correct

   The command correctly adds Read permission for User:carol on topic sales.

2. Step 2: Consider authentication and identity

   If Carol cannot read despite ACL, likely her client is not authenticating as User:carol, so ACL does not apply.

3. Final Answer:

   Carol's client is not authenticating as User:carol -> Option C

4. Quick Check:

   ACL needs matching user identity = A [OK]

Hint: ACLs depend on correct user authentication [OK]

Common Mistakes:

• Thinking Write permission is needed to read
• Assuming Kafka broker restart is required for ACL changes
• Confusing user names in ACL commands

5. You want to allow a group of users to produce messages to topic logs but deny them from deleting the topic. Which ACL commands correctly achieve this?

hard

A. Add allow ACL for Produce operation only; deny is not needed because deny is default

B. Add allow ACL for Produce operation and add deny ACL for Delete operation for the user group

C. Add allow ACL for Produce and Delete operations for the user group

D. Add deny ACL for Produce and allow ACL for Delete operations for the user group

Solution

1. Step 1: Understand permission requirements

   The users should be allowed to produce messages but denied from deleting the topic.

2. Step 2: Use allow and deny ACLs appropriately

   We add an allow ACL for Produce operation and explicitly add a deny ACL for Delete operation to prevent deletion.

3. Final Answer:

   Add allow ACL for Produce operation and add deny ACL for Delete operation for the user group -> Option B

4. Quick Check:

   Allow produce + deny delete = A [OK]

Hint: Use allow for produce and deny for delete explicitly [OK]

Common Mistakes:

• Assuming deny is default without adding deny ACL
• Allowing delete by mistake
• Mixing up allow and deny commands