SASL authentication in Kafka - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

SASL PLAIN Authentication Configuration Output

What will be the output of the following Kafka client configuration snippet when connecting with SASL PLAIN?

Kafka

props = {
  'security.protocol': 'SASL_PLAINTEXT',
  'sasl.mechanism': 'PLAIN',
  'sasl.jaas.config': 'org.apache.kafka.common.security.plain.PlainLoginModule required username="user1" password="pass1";'
}
print(props['security.protocol'], props['sasl.mechanism'])

A PLAINTEXT SASL_PLAIN

B SASL_PLAINTEXT PLAIN

C SASL_SSL PLAIN

D SSL SASL_PLAINTEXT

💡 Hint

Check the values assigned to 'security.protocol' and 'sasl.mechanism' keys.

The configuration sets 'security.protocol' to 'SASL_PLAINTEXT' and 'sasl.mechanism' to 'PLAIN', so printing these keys outputs 'SASL_PLAINTEXT PLAIN'.

❓ Predict Output

intermediate

SASL SCRAM Authentication Error Message

What error message will be raised if the Kafka client tries to connect using SASL SCRAM with an incorrect password?

Kafka

try:
  # Simulated connection attempt
  raise Exception('SASL authentication failed: Invalid credentials')
except Exception as e:
  print(e)

A No such mechanism supported

B Connection timeout error

C SASL authentication failed: Invalid credentials

D SSL handshake failed

💡 Hint

Focus on the exception message raised during authentication failure.

When SASL SCRAM authentication fails due to wrong password, the client typically receives an 'Invalid credentials' error message.

🔧 Debug

advanced

Identify the SASL Authentication Bug

Given the following Kafka client configuration, which option correctly identifies the bug causing SASL authentication to fail?

Kafka

props = {
  'security.protocol': 'SASL_SSL',
  'sasl.mechanism': 'PLAIN',
  'sasl.jaas.config': 'org.apache.kafka.common.security.plain.PlainLoginModule required username="admin" password="admin123"'
}
# Connection fails with authentication error

A Missing semicolon at the end of 'sasl.jaas.config' string

B Incorrect 'security.protocol' value; should be 'PLAINTEXT'

C Wrong SASL mechanism; should be 'SCRAM-SHA-256'

D Username and password must be integers

💡 Hint

Check the syntax of the JAAS config string carefully.

The JAAS config string requires a semicolon at the end to separate statements. Missing it causes authentication failure.

📝 Syntax

advanced

SASL JAAS Configuration Syntax Error

Which option contains a syntax error in the SASL JAAS configuration string?

A org.apache.kafka.common.security.plain.PlainLoginModule required username=user password=pass;

B org.apache.kafka.common.security.plain.PlainLoginModule required username='user' password='pass';

C org.apache.kafka.common.security.plain.PlainLoginModule required username="user" password="pass";

D org.apache.kafka.common.security.plain.PlainLoginModule required username="user" password="pass"

💡 Hint

Look at how username and password values are quoted.

In JAAS config, username and password must be quoted strings. Option A lacks quotes, causing syntax error.

🚀 Application

expert

Determine the Number of SASL Mechanisms Supported

Given a Kafka broker configured with SASL mechanisms: PLAIN, SCRAM-SHA-256, SCRAM-SHA-512, and GSSAPI, how many SASL mechanisms can a client choose from to authenticate?

A 2

B 3

C 5

D 4

💡 Hint

Count all listed mechanisms available for SASL authentication.

The broker supports four SASL mechanisms: PLAIN, SCRAM-SHA-256, SCRAM-SHA-512, and GSSAPI, so clients can choose any of these four.