ZooKeeper role (and KRaft replacement) in Kafka - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start a Kafka broker with ZooKeeper connection.

Kafka

bin/kafka-server-start.sh config/server.properties --override zookeeper.connect=[1]

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

Alocalhost:9092

Blocalhost:2181

Clocalhost:9093

Dlocalhost:9094

Attempts:

3 left

💡 Hint

Common Mistakes

Using Kafka broker port instead of ZooKeeper port.

The Kafka broker connects to ZooKeeper at the default port 2181 on localhost.

2fill in blank

medium

Complete the configuration to enable KRaft mode in Kafka broker.

Kafka

process.roles=[1]

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

Acontroller

Bbroker

Cbroker,controller

Dzookeeper

Attempts:

3 left

💡 Hint

Common Mistakes

Setting only 'broker' or 'controller' role alone.

In KRaft mode, the broker acts as both broker and controller, so both roles are set.

3fill in blank

hard

Fix the error in the KRaft controller quorum configuration.

Kafka

controller.quorum.voters=[1]

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

A1@localhost:9093,2@localhost:9094,3@localhost:9095

Blocalhost:9093,localhost:9094,localhost:9095

Clocalhost:9093;localhost:9094;localhost:9095

D1:localhost:9093,2:localhost:9094,3:localhost:9095

Attempts:

3 left

💡 Hint

Common Mistakes

Using colons instead of '@', or missing voter ids.

The correct format for voters is 'id@host:port' separated by commas.

4fill in blank

hard

Fill both blanks to configure the KRaft metadata log directory and cluster id.

Kafka

metadata.log.dir=[1]
cluster.id=[2]

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A/var/lib/kafka/kraft-combined-logs

B/tmp/kafka-logs

C"A1B2C3D4-E5F6-7890-1234-56789ABCDEF0"

D"12345678-1234-1234-1234-123456789abc"

Attempts:

3 left

💡 Hint

Common Mistakes

Using default log directory or invalid cluster id format.

The metadata log directory is set to a dedicated KRaft logs folder, and the cluster id is a UUID string.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps broker ids to their ports in KRaft mode.

Kafka

broker_ports = [1]: [2] for [3] in range(1, 4)}

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

Aid

Bid * 1000 + 9092

Dport

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names or incorrect port calculation.

This comprehension creates a dictionary where keys are broker ids and values are ports calculated by adding 9092 to 1000 times the id.

Practice

1. What is the main role of ZooKeeper in a Kafka cluster?

easy

A. To store Kafka messages permanently

B. To replace Kafka brokers in the cluster

C. To serve as a Kafka client for producers

D. To manage cluster coordination and metadata

Solution

1. Step 1: Understand ZooKeeper's purpose

   ZooKeeper is used to manage coordination tasks like leader election and metadata storage in Kafka clusters.

2. Step 2: Identify what ZooKeeper does not do

   ZooKeeper does not store Kafka messages or act as a client or broker replacement.

3. Final Answer:

   To manage cluster coordination and metadata -> Option D

4. Quick Check:

   ZooKeeper = cluster coordination [OK]

Hint: ZooKeeper manages coordination, not message storage [OK]

Common Mistakes:

• Thinking ZooKeeper stores Kafka messages
• Confusing ZooKeeper with Kafka brokers
• Assuming ZooKeeper acts as a client

2. Which of the following is the correct way to enable KRaft mode in Kafka's configuration?

easy

A. set kafka.broker.only=true

B. set kafka.zk.enabled=true

C. set process.roles=controller,broker

D. set zookeeper.connect=localhost:2181

Solution

1. Step 1: Identify KRaft configuration property

   KRaft mode requires setting the process.roles property to include controller and broker roles.

2. Step 2: Eliminate incorrect options

   ZooKeeper-related settings like kafka.zk.enabled=true and zookeeper.connect=localhost:2181 are not for KRaft. kafka.broker.only=true is not a valid Kafka config.

3. Final Answer:

   set process.roles=controller,broker -> Option C

4. Quick Check:

   process.roles = controller,broker [OK]

Hint: KRaft uses process.roles, not zookeeper.connect [OK]

Common Mistakes:

• Confusing ZooKeeper settings with KRaft
• Using deprecated or invalid config keys
• Assuming KRaft disables brokers

3. Given the following Kafka broker configuration snippet in KRaft mode:

process.roles=broker,controller
node.id=1
controller.quorum.voters=1@localhost:9093

What is the role of this broker?

medium

A. It acts as both broker and controller

B. It acts only as a controller, not a broker

C. It acts neither as broker nor controller

D. It acts only as a broker, not a controller

Solution

1. Step 1: Analyze process.roles value

   The value 'broker,controller' means this node acts as both broker and controller.

2. Step 2: Confirm node.id and quorum voters

   node.id=1 and controller.quorum.voters=1@localhost:9093 confirm this node is part of the controller quorum.

3. Final Answer:

   It acts as both broker and controller -> Option A

4. Quick Check:

   process.roles includes both roles [OK]

Hint: process.roles lists all roles this node performs [OK]

Common Mistakes:

• Ignoring multiple roles in process.roles
• Confusing node.id with role type
• Assuming controller.quorum.voters disables broker role

4. You try to start a Kafka cluster in KRaft mode but get an error about missing controller quorum voters. Which configuration is missing or incorrect?

medium

A. Incorrect 'process.roles' without 'broker'

B. Missing or incorrect 'controller.quorum.voters' setting

C. Missing 'zookeeper.connect' setting

D. Missing 'log.dirs' setting

Solution

1. Step 1: Understand error context

   KRaft mode requires 'controller.quorum.voters' to define controller nodes.

2. Step 2: Identify missing or wrong config

   If this setting is missing or wrong, Kafka cannot form the controller quorum, causing startup errors.

3. Final Answer:

   Missing or incorrect 'controller.quorum.voters' setting -> Option B

4. Quick Check:

   controller.quorum.voters required in KRaft [OK]

Hint: KRaft needs controller.quorum.voters set [OK]

Common Mistakes:

• Confusing ZooKeeper settings with KRaft
• Ignoring controller quorum config
• Assuming log.dirs causes quorum errors

5. You want to migrate a Kafka cluster from ZooKeeper mode to KRaft mode. Which of the following steps is essential for a successful migration?

hard

A. Configure 'process.roles' and 'controller.quorum.voters' and migrate metadata to KRaft

B. Remove all brokers and restart ZooKeeper only

C. Disable KRaft and keep using ZooKeeper indefinitely

D. Set 'zookeeper.connect' to empty string and restart brokers

Solution

1. Step 1: Understand migration requirements

   Moving to KRaft requires configuring roles and controller quorum voters and migrating metadata from ZooKeeper.

2. Step 2: Eliminate incorrect options

   The other options do not perform a proper migration to KRaft or incorrectly suggest keeping or modifying ZooKeeper.

3. Final Answer:

   Configure 'process.roles' and 'controller.quorum.voters' and migrate metadata to KRaft -> Option A

4. Quick Check:

   Migration needs roles, quorum, and metadata move [OK]

Hint: Set roles, quorum, migrate metadata for KRaft migration [OK]

Common Mistakes:

• Skipping metadata migration step
• Trying to run ZooKeeper and KRaft simultaneously
• Misconfiguring controller quorum voters