SASL authentication in Kafka - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the SASL mechanism to use SCRAM-SHA-256.

Kafka

props.put("sasl.mechanism", "[1]");

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

ASCRAM-SHA-256

BPLAIN

CGSSAPI

DOAUTHBEARER

Attempts:

3 left

💡 Hint

Common Mistakes

Using PLAIN instead of SCRAM-SHA-256

Misspelling the mechanism name

The SASL mechanism must be set to SCRAM-SHA-256 to use that authentication method.

2fill in blank

medium

Complete the code to set the SASL JAAS config with username and password.

Kafka

props.put("sasl.jaas.config", "org.apache.kafka.common.security.scram.ScramLoginModule required username=\"[1]\" password=\"secret\";");

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

Aadmin

Buser1

Cguest

Dkafka

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong username

Forgetting to escape quotes properly

The username in the JAAS config must match the Kafka user, here kafka.

3fill in blank

hard

Fix the error in the SASL mechanism property key name.

Kafka

props.put("[1]", "SCRAM-SHA-512");

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

Asasl.mech

Bsasl.mechanisms

Csasl.mechanism

Dsasl.mechanism.name

Attempts:

3 left

💡 Hint

Common Mistakes

Using plural or incorrect property keys

Adding extra suffixes to the key

The correct property key for SASL mechanism is sasl.mechanism.

4fill in blank

hard

Fill both blanks to configure SASL with SCRAM-SHA-512 and set the username.

Kafka

props.put("sasl.mechanism", "[1]");
props.put("sasl.jaas.config", "org.apache.kafka.common.security.scram.ScramLoginModule required username=\"[2]\" password=\"mypassword\";");

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

ASCRAM-SHA-512

BSCRAM-SHA-256

CkafkaUser

DadminUser

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing mechanism names

Using wrong usernames

Use SCRAM-SHA-512 for the mechanism and kafkaUser as the username.

5fill in blank

hard

Fill all three blanks to complete the SASL configuration with SCRAM-SHA-256, username, and password.

Kafka

props.put("sasl.mechanism", "[1]");
props.put("security.protocol", "[2]");
props.put("sasl.jaas.config", "org.apache.kafka.common.security.scram.ScramLoginModule required username=\"[3]\" password=\"pass123\";");

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

ASCRAM-SHA-512

BSASL_SSL

CkafkaUser

DSCRAM-SHA-256

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong security protocol

Confusing SCRAM-SHA-256 with SCRAM-SHA-512

Incorrect username

The SASL mechanism is SCRAM-SHA-256, the security protocol is SASL_SSL, and the username is kafkaUser.

Practice

1. What is the main purpose of SASL authentication in Kafka?

easy

A. To compress messages for faster transmission

B. To verify user identity before allowing access

C. To balance load between Kafka brokers

D. To encrypt data stored on disk

Solution

1. Step 1: Understand SASL role in Kafka

   SASL is a protocol used to verify who is connecting to Kafka, ensuring only authorized users can access it.

2. Step 2: Differentiate from other Kafka features

   Compression, load balancing, and disk encryption are unrelated to SASL authentication.

3. Final Answer:

   To verify user identity before allowing access -> Option B

4. Quick Check:

   SASL = user verification [OK]

Hint: SASL is about user identity, not data or load [OK]

Common Mistakes:

• Confusing SASL with encryption
• Thinking SASL manages data compression
• Mixing SASL with load balancing

2. Which of the following is the correct way to specify SASL mechanism in Kafka client configuration?

easy

A. security.protocol = SASL_PLAINTEXT

B. sasl.config = PLAIN

C. sasl.mechanism = PLAIN

D. security.mechanism = SASL

Solution

1. Step 1: Identify correct property for SASL mechanism

   The Kafka client uses sasl.mechanism to specify the SASL mechanism like PLAIN, SCRAM, etc.

2. Step 2: Check other options for correctness

   security.protocol sets protocol type, not mechanism; sasl.config is invalid; security.mechanism is not a valid property.

3. Final Answer:

   sasl.mechanism = PLAIN -> Option C

4. Quick Check:

   sasl.mechanism sets SASL type [OK]

Hint: Use sasl.mechanism to set SASL type like PLAIN [OK]

Common Mistakes:

• Using security.protocol instead of sasl.mechanism
• Writing sasl.config instead of sasl.mechanism
• Confusing property names

3. Given this Kafka client configuration snippet:

props.put("security.protocol", "SASL_SSL");
props.put("sasl.mechanism", "SCRAM-SHA-256");
props.put("sasl.jaas.config", "org.apache.kafka.common.security.scram.ScramLoginModule required username=\"user1\" password=\"pass1\";");

What will happen when the client tries to connect?

medium

A. Client connects using PLAINTEXT mechanism

B. Client connects but without encryption

C. Client fails due to missing SSL configuration

D. Client connects securely using SCRAM-SHA-256 with encrypted channel

Solution

1. Step 1: Analyze security.protocol setting

   Setting security.protocol to SASL_SSL means the client uses SASL authentication over SSL encrypted connection.

2. Step 2: Check SASL mechanism and JAAS config

   The mechanism is SCRAM-SHA-256 with proper JAAS config providing username and password, so authentication will succeed if credentials are correct.

3. Final Answer:

   Client connects securely using SCRAM-SHA-256 with encrypted channel -> Option D

4. Quick Check:

   SASL_SSL + SCRAM = secure auth [OK]

Hint: SASL_SSL means secure auth with encryption [OK]

Common Mistakes:

• Assuming SASL_SSL means no encryption
• Ignoring JAAS config for credentials
• Confusing SCRAM with PLAINTEXT

4. You have this Kafka client config:

props.put("security.protocol", "SASL_PLAINTEXT");
props.put("sasl.mechanism", "PLAIN");
props.put("sasl.jaas.config", "org.apache.kafka.common.security.plain.PlainLoginModule required username=\"admin\" password=\"admin123\";");

The client fails to authenticate. What is the most likely cause?

medium

A. Broker does not support SASL_PLAINTEXT

B. Incorrect sasl.mechanism value

C. Wrong format in sasl.jaas.config string

D. Missing SSL configuration causes failure

Solution

1. Step 1: Check security.protocol compatibility

   SASL_PLAINTEXT means SASL without encryption. Many brokers disable this for security reasons.

2. Step 2: Consider broker support

   If the broker is configured to reject SASL_PLAINTEXT connections, authentication will fail even if credentials and mechanism are correct.

3. Final Answer:

   Broker does not support SASL_PLAINTEXT -> Option A

4. Quick Check:

   Broker must allow SASL_PLAINTEXT [OK]

Hint: Check if broker allows SASL_PLAINTEXT connections [OK]

Common Mistakes:

• Assuming SSL is required for SASL_PLAINTEXT
• Misformatting sasl.jaas.config string
• Using wrong sasl.mechanism value

5. You want to configure a Kafka client to use SASL_SSL with SCRAM-SHA-512 mechanism. Which of the following is the correct minimal configuration snippet in Java?

hard

A. props.put("security.protocol", "SASL_SSL");
props.put("sasl.mechanism", "SCRAM-SHA-512");
props.put("sasl.jaas.config", "org.apache.kafka.common.security.scram.ScramLoginModule required username=\"user\" password=\"pass\";");

B. props.put("security.protocol", "SSL");
props.put("sasl.mechanism", "SCRAM-SHA-512");
props.put("sasl.jaas.config", "org.apache.kafka.common.security.scram.ScramLoginModule required username=\"user\" password=\"pass\";");

C. props.put("security.protocol", "SASL_PLAINTEXT");
props.put("sasl.mechanism", "SCRAM-SHA-256");
props.put("sasl.jaas.config", "org.apache.kafka.common.security.scram.ScramLoginModule required username=\"user\" password=\"pass\";");

D. props.put("security.protocol", "SASL_SSL");
props.put("sasl.mechanism", "PLAIN");
props.put("sasl.jaas.config", "org.apache.kafka.common.security.plain.PlainLoginModule required username=\"user\" password=\"pass\";");

Solution

1. Step 1: Match security.protocol with SASL_SSL

   To use encrypted SASL, security.protocol must be SASL_SSL.

2. Step 2: Confirm sasl.mechanism and JAAS config

   For SCRAM-SHA-512, sasl.mechanism must be SCRAM-SHA-512 and JAAS config must use ScramLoginModule with username and password.

3. Step 3: Eliminate incorrect options

   props.put("security.protocol", "SSL"); props.put("sasl.mechanism", "SCRAM-SHA-512"); props.put("sasl.jaas.config", "org.apache.kafka.common.security.scram.ScramLoginModule required username=\"user\" password=\"pass\";"); uses SSL without SASL, C uses wrong mechanism and protocol, D uses PLAIN mechanism instead of SCRAM-SHA-512.

4. Final Answer:

   Correct SASL_SSL with SCRAM-SHA-512 and proper JAAS config -> Option A

5. Quick Check:

   SASL_SSL + SCRAM-SHA-512 + JAAS = props.put("security.protocol", "SASL_SSL"); props.put("sasl.mechanism", "SCRAM-SHA-512"); props.put("sasl.jaas.config", "org.apache.kafka.common.security.scram.ScramLoginModule required username=\"user\" password=\"pass\";"); [OK]

Hint: Match protocol, mechanism, and JAAS module exactly [OK]

Common Mistakes:

• Using SSL instead of SASL_SSL
• Mismatching mechanism and JAAS module
• Using wrong SASL mechanism version