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Beginner40 questions Not started. #1 What is Apache Kafka and what problem does it solve? Not started. #2 What is a Kafka topic and how is it different from a traditional queue? Not started. #3 What is a partition in Kafka and why are they important? Not started. #4 What is an offset in Kafka? Not started. #5 What is the role of a Kafka broker? Not started. #6 What is a consumer group? Not started. #7 What is the difference between at-most-once, at-least-once, and exactly-once delivery? Not started. #8 What is the replication factor? Not started. #9 What are acks in Kafka producer configuration? Not started. #10 What is the High Watermark (HWM)? Not started. #11 What is consumer lag? Not started. #12 How do you increase the throughput of a Kafka consumer? Not started. #13 What does auto.offset.reset=earliest vs latest do? Not started. #14 What is enable.auto.commit and why is it dangerous? Not started. #15 What is Kafka's data retention and how is it configured? Not started. #16 How does Kafka differ from a traditional message queue? Not started. #17 What is a Kafka producer and how does key-based partitioning work? Not started. #18 How does Kafka guarantee message ordering? Not started. #19 What are Kafka's built-in compression types? Not started. #20 What is a dead letter queue (DLT) in Kafka? Not started. #21 What is the ISR (In-Sync Replicas) set? Not started. #22 What is ZooKeeper's role in traditional Kafka and what replaced it? Not started. #23 What is the default log retention period in Kafka? Not started. #24 How do you view Kafka consumer group lag? Not started. #25 What is min.insync.replicas and when does it matter? Not started. #26 What is a Kafka record/message structure? Not started. #27 What happens when a Kafka broker goes down? Not started. #28 What is log compaction and when would you use it? Not started. #29 What is the difference between kafka-console-producer and kafka-console-consumer? Not started. #30 What serialization formats are commonly used with Kafka? Not started. #31 What is the bootstrap.servers configuration on a Kafka client? Not started. #32 What ports does a Kafka broker listen on by default, and how are they configured? Not started. #33 How does a consumer know which offset to start from? Not started. #34 What is Kafka Streams? Not started. #35 What is Kafka Connect? Not started. #36 What is the difference between Kafka's @KafkaListener and manual polling? Not started. #37 How are records converted to and from bytes in Kafka clients and in Kafka Connect? Not started. #38 What is the purpose of the __consumer_offsets topic? Not started. #39 What is the kafka-topics.sh tool used for? Not started. #40 What happens if a consumer group has more consumers than partitions? Intermediate35 questions Not started. #41 Explain the producer request lifecycle with acks=all in detail. Not started. #42 What is the difference between LEO and HWM? Why does it matter for consumers? Not started. #43 How does Kafka handle leader election when a broker fails? Not started. #44 How would you tune a Kafka producer for maximum throughput? Not started. #45 What causes consumer rebalancing and how can you minimize it? Not started. #46 What is the difference between Kafka's request queue and the Purgatory? Not started. #47 How do you safely perform a rolling upgrade of a Kafka cluster? Not started. #48 What is the significance of max.in.flight.requests.per.connection in relation to ordering? Not started. #49 Explain the Kafka controller's responsibilities in KRaft mode. Not started. #50 What is the OS page cache and why does it matter for Kafka performance? Not started. #51 How does Kafka use sendfile() for zero-copy transfer? Not started. #52 What is partition reassignment and when do you need it? Not started. #53 What is the difference between sticky and cooperative sticky partition assignment? Not started. #54 How do you prevent consumer lag from growing under high load? Not started. #55 What is Kafka's log segment and why does it matter? Not started. #56 How would you debug a 'LEADER_NOT_AVAILABLE' error in production? Not started. #57 What is unclean leader election and why is it dangerous? Not started. #58 What is the significance of num.partitions for a topic? Not started. #59 How do you reset consumer offsets to reprocess messages? Not started. #60 What is Kafka's inter-broker replication protocol? Not started. #61 How does Kafka guarantee message ordering with multiple producers? Not started. #62 What is the impact of increasing Kafka's JVM heap size? Not started. #63 What is Kafka's wire protocol and how does versioning work? Not started. #64 What are the main JMX metrics to monitor for a healthy Kafka cluster? Not started. #65 How does a Kafka producer handle a NOT_LEADER_OR_FOLLOWER error? Not started. #66 How does Kafka achieve low latency with acks=all? Not started. #67 What is rack awareness in Kafka and why is it important? Not started. #68 What is Kafka's RecordAccumulator and how does it buffer messages? Not started. #69 How does Kafka handle message schema evolution, and what do teams do about it? Not started. #70 What is the difference between Kafka's Fetch API and consumer.poll()? Not started. #91 Why can a handful of failures flood a dead letter queue with thousands of messages? Not started. #92 What does a minimum-viable DLQ configuration need, and why does each setting matter? Not started. #93 How does Kafka's design deal with failing nodes and the cost of the network? Not started. #161 What did Kafka 4.0 remove regarding ZooKeeper, and what must a ZooKeeper-mode cluster do before it can upgrade to 4.0? Not started. #163 What are Kafka share groups, and when would you use one instead of a consumer group? Advanced22 questions Not started. #71 Explain Kafka's exactly-once semantics implementation end-to-end. Not started. #72 What is the Kafka Raft (KRaft) consensus algorithm and how does it differ from ZooKeeper-based metadata management? Not started. #73 How does Kafka handle log truncation during replica recovery? Not started. #74 What is the epoch fencing mechanism in Kafka transactions? Not started. #75 How does Kafka's TimingWheel work and why is it used in Purgatory? Not started. #76 Explain the Kafka consumer's heartbeat threading model and how it relates to max.poll.interval.ms. Not started. #77 What is Kafka's sparse index format and how does binary search work on it? Not started. #78 How would you diagnose and fix high producer latency (P99 > 500ms)? Not started. #79 What is the Outbox Pattern and how does Kafka enable it? Not started. #80 How would you implement the Saga pattern using Kafka? Not started. #81 Explain event sourcing with Kafka. What are the trade-offs? Not started. #82 What is the __transaction_state topic and how does it work? Not started. #83 How would you handle a Kafka cluster with millions of partitions? Not started. #84 What is the Kafka Mirror Maker 2 (MM2) and how does multi-cluster replication work? Not started. #85 Explain the Kafka consumer group coordinator and rebalance protocol in detail. Not started. #86 How does Kafka handle backpressure from slow consumers? Not started. #87 How does event sourcing relate to read-optimized state in Kafka, and how does CQRS fit in? Not started. #88 How does Kafka's compaction work internally? What is the cleaner thread? Not started. #89 What is the effect of fsync on Kafka performance and when should you configure it? Not started. #90 How would you design a Kafka-based event-driven microservices architecture? Not started. #162 How does the KIP-848 consumer rebalance protocol differ from the classic protocol, and how does a consumer opt in? Not started. #165 What does Kafka 4.2 add to Kafka Streams for failing records, and what limits does the new Streams rebalance protocol have? Spring30 questions Not started. #101 How do you configure a Kafka consumer in Spring Boot? Not started. #102 How do you produce messages with KafkaTemplate? Not started. #103 How do you configure retry and dead letter topics in Spring Kafka? Not started. #104 How do you configure Kafka transactions in Spring Kafka? Not started. #105 How do you set up manual offset commits in Spring Kafka? Not started. #106 What is the difference between concurrency and partitions in Spring Kafka's listener container? Not started. #107 How do you handle deserialization errors in Spring Kafka? Not started. #108 How do you implement a batch @KafkaListener in Spring Kafka? Not started. #109 What is spring.kafka.consumer.isolation-level and when do you need it? Not started. #110 How do you test Kafka listeners in Spring Boot? Not started. #111 How do you configure Spring Kafka for JSON serialization with type information? Not started. #112 What is SeekToCurrentErrorHandler (now DefaultErrorHandler) in Spring Kafka? Not started. #113 How do you configure multiple @KafkaListener annotations for the same topic with different group IDs? Not started. #114 What is spring.kafka.listener.missing-topics-fatal? Not started. #115 How does @KafkaListener handle partition assignment and offset control? Not started. #116 What is the KafkaAdmin bean and how do you use it to manage topics? Not started. #117 How do you write a Spring Kafka integration test without external Kafka? Not started. #118 How do you configure the consumer to start from the beginning for a new application deployment? Not started. #119 What is spring.kafka.listener.ack-mode RECORD vs BATCH vs MANUAL? Not started. #120 How does Spring Kafka's @RetryableTopic differ from blocking retries with DefaultErrorHandler? Not started. #121 How do you implement request-reply pattern with Spring Kafka? Not started. #122 What is the difference between ProducerFactory and KafkaTemplate in Spring Kafka? Not started. #123 How do you use Kafka headers in Spring Kafka? Not started. #124 How do you configure consumer listener concurrency for optimal throughput? Not started. #125 What happens if a @KafkaListener throws an uncaught exception? Not started. #126 How do you configure Spring Kafka consumer groups for multi-tenancy? Not started. #127 What is the difference between DefaultErrorHandler and CommonErrorHandler in Spring Kafka? Not started. #128 How do you configure Spring Kafka for Avro with Confluent Schema Registry? Not started. #129 What is spring.kafka.streams and how do you use Kafka Streams in Spring Boot? Not started. #130 How do you control the number of messages processed per @KafkaListener invocation? Scenario23 questions Not started. #94 Your DLQ has 25,000 unread messages that built up over the last week. Walk through how you'd triage it. Not started. #141 Your Kafka cluster shows UnderReplicatedPartitions > 0. Walk through your debugging steps. Not started. #142 A consumer group suddenly shows 100,000 messages of consumer lag. How do you respond? Not started. #143 You're seeing duplicate messages in your consumer application. How do you identify the source and fix it? Not started. #144 How do you safely add a new topic and deploy a new consumer without downtime? Not started. #145 A production broker runs out of disk space. What happens and how do you recover? Not started. #146 Your Spring Boot Kafka consumer stops consuming after processing a malformed message. How do you fix it? Not started. #147 How do you migrate a Kafka topic to a new cluster with zero data loss? Not started. #148 Design a Kafka topic schema for an e-commerce order processing system. Not started. #149 A Kafka Streams application is falling behind. How do you scale it? Not started. #150 How do you implement exactly-once delivery in a Kafka-to-database pipeline? Not started. #151 What would you check first if consumers are reading the same messages multiple times after a deployment? Not started. #152 Design a high-throughput event ingestion pipeline with Kafka. Not started. #153 A Kafka producer is experiencing high p99 latency. List 5 potential causes and fixes. Not started. #154 How would you implement an audit log system using Kafka? Not started. #155 Explain how you'd handle a multi-region Kafka deployment for disaster recovery. Not started. #156 How do you handle schema evolution when you have 50 consumers reading a Kafka topic? Not started. #157 What's your strategy for monitoring Kafka in production with 100+ topics? Not started. #158 How do you safely increase the partition count of an existing Kafka topic? Not started. #159 What is the maximum number of consumer groups that can read the same Kafka topic simultaneously? Not started. #160 How would you debug a 'Network Exception: Disconnected' error in a Kafka producer? Not started. #164 A colleague says "Kafka has diskless topics now, so we can drop the broker disks." How do you respond? Not started. #166 A team wants to move a running consumer group to the new rebalance protocol without downtime. What do they do, and what do they check first?