Kafka on Kubernetes (Strimzi) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Strimzi in the context of Kafka on Kubernetes?

Strimzi is an open-source project that makes it easy to run Apache Kafka on Kubernetes by providing operators to manage Kafka clusters automatically.

intermediate

What is the role of the Kafka Operator in Strimzi?

The Kafka Operator watches for Kafka custom resources and manages the Kafka cluster lifecycle, including deployment, scaling, and upgrades.

beginner

Which Kubernetes resource does Strimzi use to define a Kafka cluster?

Strimzi uses a Custom Resource Definition (CRD) called Kafka to define the desired state of a Kafka cluster.

intermediate

How does Strimzi handle Kafka broker configuration changes?

Strimzi updates the Kafka brokers automatically by rolling restarts when configuration changes are applied to the Kafka custom resource.

beginner

Name one benefit of running Kafka on Kubernetes with Strimzi.

One benefit is automated management of Kafka clusters, reducing manual work and improving reliability through Kubernetes-native tools.

What does Strimzi primarily provide for Kafka on Kubernetes?

A A new Kafka client library

B A Kafka message broker replacement

C Operators to manage Kafka clusters

D A Kubernetes networking plugin

Strimzi provides operators that automate Kafka cluster management on Kubernetes.

Which Kubernetes object type does Strimzi use to represent a Kafka cluster?

A Service

B Custom Resource (Kafka CRD)

C Pod

D ConfigMap

Strimzi uses a Custom Resource Definition (CRD) named Kafka to define Kafka clusters.

How does Strimzi apply configuration changes to Kafka brokers?

A Rolling restart managed by the operator

B No restarts needed

C Manual restart by the user

D Delete and recreate the cluster

Strimzi performs rolling restarts automatically to apply configuration changes without downtime.

Which component in Strimzi watches Kafka custom resources and manages cluster lifecycle?

A Kafka Operator

B Kafka Broker

C Zookeeper

D Kubernetes Scheduler

The Kafka Operator is responsible for managing Kafka clusters based on custom resources.

What is a key advantage of using Strimzi for Kafka on Kubernetes?

A It replaces Kafka with a simpler system

B It provides a GUI for Kafka

C It removes the need for Zookeeper

D It automates Kafka cluster management

Strimzi automates deployment, scaling, and upgrades of Kafka clusters on Kubernetes.

Explain how Strimzi simplifies running Kafka on Kubernetes.

Think about what tasks Strimzi automates for you.

Describe the role of Custom Resource Definitions (CRDs) in Strimzi.

CRDs tell Kubernetes about new resource types like Kafka.

Practice

1. What is the main purpose of Strimzi when running Kafka on Kubernetes?

easy

A. To simplify and automate Kafka cluster management on Kubernetes

B. To replace Kubernetes with a new container orchestration system

C. To provide a graphical user interface for Kafka topics

D. To convert Kafka messages into SQL queries automatically

Solution

1. Step 1: Understand Strimzi's role

   Strimzi is designed to help run Kafka on Kubernetes by managing Kafka clusters easily.

2. Step 2: Identify the correct purpose

   It automates pod management, storage, and recovery, simplifying Kafka operations on Kubernetes.

3. Final Answer:

   To simplify and automate Kafka cluster management on Kubernetes -> Option A

4. Quick Check:

   Strimzi = Kafka automation on Kubernetes [OK]

Hint: Strimzi automates Kafka on Kubernetes, not replaces or adds UI [OK]

Common Mistakes:

• Thinking Strimzi replaces Kubernetes
• Confusing Strimzi with Kafka UI tools
• Assuming Strimzi converts Kafka messages to SQL

2. Which of the following is the correct command to apply a Kafka cluster YAML file named kafka-cluster.yaml using Strimzi on Kubernetes?

easy

A. kubectl run kafka-cluster.yaml

B. strimzi create kafka-cluster.yaml

C. kubectl apply -f kafka-cluster.yaml

D. kafka apply kafka-cluster.yaml

Solution

1. Step 1: Recall how Kubernetes applies YAML files

   Kubernetes uses kubectl apply -f filename.yaml to create or update resources.

2. Step 2: Match the command to Strimzi usage

   Strimzi uses Kubernetes resources, so applying the Kafka cluster YAML is done with kubectl apply -f.

3. Final Answer:

   kubectl apply -f kafka-cluster.yaml -> Option C

4. Quick Check:

   Apply YAML with kubectl apply -f [OK]

Hint: Use kubectl apply -f for YAML files on Kubernetes [OK]

Common Mistakes:

• Using non-existent 'strimzi create' command
• Confusing kubectl run with apply
• Trying to use kafka CLI for Kubernetes YAML

3. Given the following YAML snippet for a Kafka cluster managed by Strimzi:

apiVersion: kafka.strimzi.io/v1beta2
kind: Kafka
metadata:
  name: my-cluster
spec:
  kafka:
    replicas: 3
    storage:
      type: ephemeral
  zookeeper:
    replicas: 3
    storage:
      type: ephemeral

What will be the number of Kafka broker pods created in the Kubernetes cluster?

medium

A. 3

B. 0

C. 6

D. 1

Solution

1. Step 1: Identify Kafka replicas in YAML

   The replicas field under kafka is set to 3, meaning 3 Kafka broker pods.

2. Step 2: Understand pod creation

   Strimzi creates one pod per replica, so 3 Kafka broker pods will be created.

3. Final Answer:

   3 -> Option A

4. Quick Check:

   Kafka replicas = 3 pods [OK]

Hint: Kafka replicas number = Kafka pods count [OK]

Common Mistakes:

• Adding Kafka and Zookeeper replicas together
• Confusing ephemeral storage with pod count
• Assuming default pod count if replicas missing

4. You applied a Kafka cluster YAML with 3 replicas, but only 1 Kafka pod is running. Which of the following is the most likely cause?

medium

A. Kafka storage type is set to ephemeral

B. The YAML file has replicas: 1 under Kafka section

C. Zookeeper replicas are set to 1

D. Strimzi operator is not installed or running

Solution

1. Step 1: Check Kafka replicas in YAML

   If YAML specifies 3 replicas, pod count should be 3, so replicas: 1 is unlikely.

2. Step 2: Consider Strimzi operator role

   Strimzi operator manages Kafka pods. If it is missing or not running, pods won't be created properly.

3. Final Answer:

   Strimzi operator is not installed or running -> Option D

4. Quick Check:

   Operator missing = pods not managed [OK]

Hint: Check Strimzi operator status if pods don't match replicas [OK]

Common Mistakes:

• Blaming Zookeeper replicas for Kafka pod count
• Thinking ephemeral storage stops pod creation
• Assuming YAML replicas value is always correct

5. You want to update your Kafka cluster managed by Strimzi to use persistent storage instead of ephemeral. Which YAML snippet correctly changes the Kafka storage to persistent with 10Gi volume size?

hard

A. storage:
type: persistent-claim
size: 10Gi

B. storage:
type: persistent-claim
volumeClaimTemplate:
spec:
resources:
requests:
storage: 10Gi

C. storage:
type: persistent
size: 10Gi

D. storage:
persistentVolume:
size: 10Gi

Solution

1. Step 1: Understand Strimzi persistent storage syntax

   Strimzi uses persistent-claim type with a volumeClaimTemplate to define PVC size.

2. Step 2: Identify correct YAML structure

   storage: type: persistent-claim volumeClaimTemplate: spec: resources: requests: storage: 10Gi correctly uses volumeClaimTemplate.spec.resources.requests.storage: 10Gi to request 10Gi persistent volume.

3. Final Answer:

   storage: type: persistent-claim volumeClaimTemplate: spec: resources: requests: storage: 10Gi -> Option B

4. Quick Check:

   Persistent storage needs volumeClaimTemplate with size [OK]

Hint: Use volumeClaimTemplate for persistent storage size in Strimzi [OK]

Common Mistakes:

• Using 'size' directly under storage without volumeClaimTemplate
• Using wrong storage type like 'persistent'
• Confusing persistentVolume with persistent-claim