Prev Next

Integration / Apache Kafka Interview questions

Define replication in Kafka?

Replication means each partition's data is copied to multiple brokers, not just stored on one, so the cluster can survive a broker failure without losing data or availability. The number of copies is set per topic via the replication factor — a replication factor of 3 means every partition has one leader replica and two follower replicas, each living on a different broker.

kafka-topics.sh --create --topic orders --partitions 3 --replication-factor 3 --bootstrap-server localhost:9092

Followers continuously fetch new records from their partition's leader to stay caught up; a follower that's fully caught up is considered part of the in-sync replica (ISR) set. If the broker hosting the leader fails, Kafka can promote one of the in-sync followers to be the new leader, so the partition keeps serving reads and writes with no data loss, as long as at least one in-sync replica survived the failure.

What does a replication factor of 3 mean for a partition?
What can happen if the broker hosting a partition's leader fails?

More Related questions...

What is a Kafka topic? Mention some of the Apache Kafka terminologies. What is the Global Unique identifier of a Kafka Message? What is a partition in Kafka? What is a Kafka producer? What is Apache Kafka? Explain the role of the ZooKeeper in Kafka. What is a Kafka consumer? What is Apache ZooKeeper? What is a consumer group in Kafka? What is a Kafka broker? Difference between Apache Kafka and Confluent Kafka. Define replication in Kafka? Kafka's zero-copy principle. What is KRaft mode in Kafka? Explain sequential I/O principle in Kafka. What are the types of message delivery semantics in Kafka? What is a Kafka offset used for? List the core APIs provided by Kafka? What is the purpose of a Kafka topic's retention policy? Describe the role of a partition leader in Kafka? What is a Kafka Connect connector? What are Kafka Streams used for? How do you create a topic using the Kafka CLI? What is a serializer in Kafka producer configuration? How do you list existing topics in a Kafka cluster? Why is Kafka better suited than a traditional message queue for high-throughput event streaming? How does Kafka differ from RabbitMQ? What is the difference between at-least-once, at-most-once, and exactly-once delivery semantics? How does Kafka's KRaft controller quorum manage cluster metadata? Why should you configure min.insync.replicas alongside acks=all? How does Kafka handle partition leader election? When should you increase the number of partitions for a topic? What happens when a consumer in a group fails to send a heartbeat in time? Explain the execution flow of a Kafka producer sending a message to a broker? How can you optimize Kafka producer throughput? How do you troubleshoot consumer lag in a Kafka application? Why is the in-sync replica (ISR) set important for durability? Explain the lifecycle of a Kafka consumer group rebalance? How does Kafka achieve exactly-once semantics with idempotent producers and transactions? What is the difference between log compaction and log deletion cleanup policies? How do you implement a custom partitioner in Kafka? How does Kafka Streams manage local state using state stores? Which is better and why: the classic consumer rebalance protocol or the new KIP-848 protocol? How do you integrate a schema registry with Kafka producers and consumers? Explain the internal working of Kafka's replication protocol between leader and follower brokers? How do you configure tiered storage for a Kafka topic? What is the difference between Kafka Connect source and sink connectors? How does Kafka support message compression? When would you choose the cooperative sticky partition assignment strategy? How do you secure a Kafka cluster with SASL and ACLs? Why should unclean leader election be disabled in most production clusters? How do you configure MirrorMaker for cross-cluster replication? Explain the execution flow of a Kafka Streams topology processing a record? How does Kafka report and expose broker and consumer metrics for monitoring? Why doesn't increasing partition count always improve throughput? How do you migrate a Kafka cluster from ZooKeeper mode to KRaft mode? What is the difference between Kafka's Queues feature (KIP-932) and traditional partitioned consumption?
Show more question and Answers...

Akka interview questions

Comments & Discussions

Interviews Questions

About Javapedia.net

Javapedia.net is for Java and J2EE developers, technologist and college students who prepare of interview. Also this site includes many practical examples.

This site is developed using J2EE technologies by Steve Antony, a senior Developer/lead at one of the logistics based company.

Follow Javapedia updates

contact: javatutorials2016[at]gmail[dot]com

Kindly consider donating for maintaining this website. Thanks.

Copyright © 2026, javapedia.net, all rights reserved. · .

DMCA.com Protection Status