Standalone vs distributed mode in Kafka - Quick Revision & Key Differences

Recall & Review

beginner

What is standalone mode in Kafka?

Standalone mode runs Kafka on a single machine where all components (broker, zookeeper) run together. It is simple and used for development or testing.

beginner

What is distributed mode in Kafka?

Distributed mode runs Kafka across multiple machines. Brokers and Zookeeper run separately to provide fault tolerance and scalability.

intermediate

Why use distributed mode instead of standalone mode?

Distributed mode allows Kafka to handle more data, stay available if some machines fail, and scale by adding more servers.

beginner

Name one limitation of standalone mode.

Standalone mode cannot handle large workloads or provide fault tolerance because it runs on a single machine.

intermediate

How does Kafka ensure reliability in distributed mode?

Kafka replicates data across multiple brokers and uses Zookeeper to manage cluster state, so if one broker fails, others keep working.

What does Kafka run in standalone mode?

A Only brokers on multiple machines

B Multiple brokers on different machines

C Only Zookeeper on one machine

D All components on one machine

Standalone mode runs all Kafka components on a single machine.

Which mode provides fault tolerance in Kafka?

A Neither mode

B Standalone mode

C Distributed mode

D Both modes

Distributed mode replicates data and runs on multiple machines to provide fault tolerance.

Why is standalone mode mainly used?

A For production with high traffic

B For development and testing

C For distributed computing

D For cloud deployment

Standalone mode is simple and used mainly for development or testing.

What role does Zookeeper play in distributed mode?

A Manages cluster state and coordination

B Stores all Kafka messages

C Runs the Kafka producer

D Manages client connections

Zookeeper manages cluster state and helps coordinate brokers in distributed mode.

Which is a key benefit of distributed mode?

A Scalability and fault tolerance

B No need for replication

C Runs on a single machine

D Simpler setup

Distributed mode allows Kafka to scale and stay available even if some machines fail.

Explain the difference between standalone and distributed mode in Kafka.

Think about how many machines run Kafka components and what benefits that brings.

Why is distributed mode preferred for production Kafka deployments?

Consider what happens if one machine fails in production.

Practice

1. What is the main purpose of running Kafka Connect in standalone mode?

easy

A. To run multiple workers for high scalability

B. To run Kafka Connect in a single process for simple or testing use

C. To enable fault tolerance across multiple machines

D. To connect Kafka with distributed databases automatically

Solution

1. Step 1: Understand standalone mode context

   Standalone mode runs Kafka Connect in one process, suitable for simple or testing scenarios.

2. Step 2: Compare with distributed mode

   Distributed mode runs multiple workers for scalability and fault tolerance, unlike standalone mode.

3. Final Answer:

   To run Kafka Connect in a single process for simple or testing use -> Option B

4. Quick Check:

   Standalone mode = single process for testing [OK]

Hint: Standalone = single process, simple use [OK]

Common Mistakes:

• Confusing standalone with distributed mode
• Thinking standalone supports fault tolerance
• Assuming standalone is for large scale pipelines

2. Which of the following is the correct command to start Kafka Connect in distributed mode?

easy

A. kafka-connect.sh start-standalone

B. connect-standalone.sh config/connect-standalone.properties

C. kafka-connect.sh start-distributed

D. connect-distributed.sh config/connect-distributed.properties

Solution

1. Step 1: Identify the script for distributed mode

   The script connect-distributed.sh is used to start Kafka Connect in distributed mode.

2. Step 2: Confirm the configuration file

   The configuration file config/connect-distributed.properties is the standard config for distributed mode.

3. Final Answer:

   connect-distributed.sh config/connect-distributed.properties -> Option D

4. Quick Check:

   Distributed mode uses connect-distributed.sh [OK]

Hint: Distributed mode uses connect-distributed.sh script [OK]

Common Mistakes:

• Using connect-standalone.sh for distributed mode
• Mixing config files between modes
• Assuming kafka-connect.sh is a valid command

3. Given the following scenario: You start Kafka Connect with connect-standalone.sh and add two connectors. What will happen if the process crashes?

medium

A. Both connectors will automatically restart on another worker

B. Connectors will continue running without interruption

C. The connectors will stop and require manual restart

D. Kafka Connect will switch to distributed mode automatically

Solution

1. Step 1: Understand standalone mode fault tolerance

   Standalone mode runs in a single process without fault tolerance or automatic recovery.

2. Step 2: Consequence of process crash

   If the process crashes, connectors stop and need manual restart because no other worker is available.

3. Final Answer:

   The connectors will stop and require manual restart -> Option C

4. Quick Check:

   Standalone mode lacks automatic recovery [OK]

Hint: Standalone mode needs manual restart after crash [OK]

Common Mistakes:

• Assuming automatic failover in standalone mode
• Thinking distributed mode starts automatically
• Believing connectors run independently of the process

4. You configured Kafka Connect in distributed mode but notice that only one worker is running and no failover happens. What is the likely cause?

medium

A. You started Kafka Connect with connect-standalone.sh instead of connect-distributed.sh

B. You did not configure the Kafka cluster correctly

C. You forgot to add connectors to the worker

D. Distributed mode does not support multiple workers

Solution

1. Step 1: Check the startup script used

   If connect-standalone.sh is used, only one worker runs without failover, even if config is for distributed mode.

2. Step 2: Understand distributed mode requirements

   Distributed mode requires starting with connect-distributed.sh to run multiple workers and enable failover.

3. Final Answer:

   You started Kafka Connect with connect-standalone.sh instead of connect-distributed.sh -> Option A

4. Quick Check:

   Wrong startup script causes single worker [OK]

Hint: Use connect-distributed.sh to run multiple workers [OK]

Common Mistakes:

• Assuming config alone enables distributed mode
• Believing distributed mode runs with standalone script
• Ignoring startup script importance

5. You have a data pipeline that must handle high volume and remain available even if one worker fails. Which Kafka Connect mode should you choose and why?

hard

A. Distributed mode, because it supports multiple workers and fault tolerance

B. Standalone mode, because it is simpler to configure

C. Standalone mode, because it automatically restarts connectors on failure

D. Distributed mode, because it runs connectors in a single process

Solution

1. Step 1: Analyze pipeline requirements

   High volume and availability require scalability and fault tolerance.

2. Step 2: Match requirements to Kafka Connect modes

   Distributed mode runs multiple workers and supports fault tolerance, meeting these needs.

3. Final Answer:

   Distributed mode, because it supports multiple workers and fault tolerance -> Option A

4. Quick Check:

   High volume + fault tolerance = distributed mode [OK]

Hint: Choose distributed mode for scalability and fault tolerance [OK]

Common Mistakes:

• Choosing standalone for high availability
• Thinking standalone auto-restarts connectors
• Misunderstanding distributed mode runs single process