Kafka on Kubernetes (Strimzi) - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Strimzi Kafka Cluster Custom Resource

Which field in the Strimzi Kafka custom resource defines the number of Kafka broker replicas?

A spec.kafka.brokers.count

B spec.zookeeper.replicas

C metadata.replicas

D spec.kafka.replicas

💡 Hint

Think about where the Kafka broker count is configured inside the Kafka resource spec.

The spec.kafka.replicas field sets how many Kafka broker pods will run. The spec.zookeeper.replicas controls Zookeeper nodes, and metadata.replicas is not a valid field here.

💻 Command Output

intermediate

Output of Kafka Topic List Command in Strimzi

What is the output of this command when run inside a Kafka pod managed by Strimzi?

bin/kafka-topics.sh --bootstrap-server localhost:9092 --list

A No topics found

B Error: Could not connect to bootstrap server

C

my-topic
another-topic

D Usage: kafka-topics.sh [options]

💡 Hint

Assume the Kafka cluster has two topics named 'my-topic' and 'another-topic'.

The command lists all topics in the Kafka cluster. If topics exist, their names are printed line by line.

❓ Configuration

advanced

Correct YAML for Kafka User Authentication with TLS

Which YAML snippet correctly configures a KafkaUser resource with TLS authentication in Strimzi?

A

apiVersion: kafka.strimzi.io/v1beta2
kind: KafkaUser
metadata:
  name: my-user
spec:
  authentication:
    type: tls

B

apiVersion: kafka.strimzi.io/v1beta2
kind: KafkaUser
metadata:
  name: my-user
spec:
  auth:
    type: tls

C

apiVersion: kafka.strimzi.io/v1beta2
kind: KafkaUser
metadata:
  name: my-user
spec:
  authentication:
    tls: true

D

apiVersion: kafka.strimzi.io/v1beta2
kind: KafkaUser
metadata:
  name: my-user
spec:
  authentication:
    type: scram-sha-512

💡 Hint

Look for the correct field names and values for TLS authentication.

The authentication.type field must be set to tls to enable TLS authentication. Option A uses an invalid field auth, B uses invalid tls: true, and D configures SCRAM instead of TLS.

❓ Troubleshoot

advanced

Troubleshooting Kafka Broker CrashLoopBackOff in Strimzi

You see a Kafka broker pod stuck in CrashLoopBackOff after deploying Strimzi Kafka cluster. Which of these is the most likely cause?

A Incorrect TLS certificates or missing secrets for broker authentication

B Zookeeper pods are running normally

C KafkaUser resource is missing

D Kafka topics are empty

💡 Hint

Think about what can cause Kafka broker pods to fail starting repeatedly.

Kafka brokers require valid TLS certificates and secrets to start properly. Missing or invalid certificates cause startup failures and CrashLoopBackOff. Zookeeper running normally or empty topics do not cause broker pod crashes. Missing KafkaUser affects clients, not brokers.

🔀 Workflow

expert

Order of Steps to Upgrade Kafka Cluster with Strimzi

Arrange the correct order of steps to safely upgrade a Kafka cluster managed by Strimzi without downtime.

A 1,3,4,2

B 4,1,2,3

C 4,2,1,3

D 1,4,2,3

💡 Hint

Think about what must be done before changing the cluster and what to verify after.

First, backup data and configs to prevent data loss. Then update the Kafka resource to trigger upgrade. Next, verify new pods are ready. Finally, check cluster health and topic availability to confirm success.