Kafka Cluster Setup & Internals Explained | Leader, Replica, ISR Deep Dive | Kafka Tutorial #4

Selenium Express July 1, 2025
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Welcome to the ultimate Apache Kafka Cluster Setup and Internals Deep Dive — a 2.5-hour hands-on tutorial covering everything you need to know to set up and truly understand a Kafka cluster in both Zookeeper-based and KRaft mode (no Zookeeper) environments. This video is designed to help you master Kafka architecture, leader-follower mechanics, replica assignment, in-sync replica (ISR) logic, and much more — from the ground up. 📌 What’s Covered: Kafka cluster setup (3-node configuration) Topics, partitions, leaders, and replicas Kafka Controller internals ISR and how failover happens Kafka metadata and controller quorum Kafka 4.x cluster setup (No Zookeeper / KRaft Mode) ✅ Whether you're preparing for an interview, running Kafka in production, or just want to understand the internals the way they were meant to be, this deep dive will help you build solid Kafka intuition. Timestamp ------------------- 00:00:00 Intro -Kafka Foundations Tutorial 00:01:15 Start Kafka (KRaft mode) 00:03:27 3‑Partition Topic on Single Broker 00:06:04 Topic inside a Cluster 00:12:20 3‑Node Cluster Setup (Zookeeper Demo) 00:23:38 Cluster Topic Creation Demo 00:28:44 First Look at Leaders 00:30:59 First Look at Replicas 00:35:12 Leader vs Replica : Duties 00:41:34 Replication Factor vs Broker Count 00:43:50 Leader & Follower on Same Broker? 00:50:14 One Leader per Partition Rule 00:52:13 KAFKA 4 UPGRADE – KRaft (No Zookeeper) 00:54:16 Kafka Controller Explained 00:57:13 Broker/Controller Failure Demo 00:58:44 3‑Broker KRaft Cluster Spin‑up 01:01:00 Reading `kafka-metadata-quorum` 01:05:23 Controller Election Walk‑through 01:08:47 Leader Allocation Logic 01:11:07 Controller Responsibilities Recap 01:12:05 Producer Metadata Request Path 01:16:32 Allocating Follower Replicas 01:21:38 Producer–Leader–Follower Demo 01:26:15 Follower Work Explained 01:27:45 Follower‑to‑Leader Failover 01:28:35 In‑Sync Replicas Hands‑On 01:35:11 Inside the ISR Mechanism 01:39:35 Staying in the ISR List 01:44:49 End‑to‑End Produce/Consume 01:47:04 Min‑ISR Concept 01:48:47 Setting Min‑ISR on a Topic 01:59:43 Full Kafka 4 Cluster Setup (No ZK) 02:04:06 Broker 1 `server.properties` 02:07:12 Controller Port Config 02:08:45 Broker 2 & 3 Configs 02:11:33 Initial Controller IDs 02:16:28 Generating Cluster & Broker IDs 02:22:28 Controller Quorum Voters 02:26:47 Launch All 3 Nodes #apachekafka #kafkatutorial #kafkaforbeginners For More free/paid courses visit www.seleniumexpress.com LINKS AND FREE LEARNING RESOURCES ======== Watch my new mock interview series for java developers https://youtu.be/yX2w-Sof95s Watch Spring boot Hot topics https://youtu.be/CUQWZHjuq-w Java Interview / Question and Answer series https://youtu.be/Y1uGGTrBYKw Explain spring Bean Lifecycle https://youtu.be/hUYGGqoXEPc spring core https://www.youtube.com/watch?v=r2Q0Jzl2qMQ&list=PL3NrzZBjk6m-nYX072dSaGfyCJ59Q5TEi spring mvc https://www.youtube.com/watch?v=zCHrZdJODg4&list=PL3NrzZBjk6m-OSeL3DRMD_ISa0u-9c1l1 spring mvc intermediate https://www.youtube.com/watch?v=40YaLHbrwrY&list=PL3NrzZBjk6m_2jw8sC0BkEwSPFHxgQDWr Spring JDBC https://www.youtube.com/watch?v=5j_vh1b9dV8&list=PL3NrzZBjk6m-rYTKze-5Y5RvU8eykal4j spring live project https://www.youtube.com/watch?v=m_b_FwDjAXM&list=PL3NrzZBjk6m-9CVPueDLLermojwtfuW_f SPRING SECURITY COURSE[NEW] https://youtu.be/NMNLozLGT1s For more courses visit https://www.seleniumexpress.com Any time you are getting stuck with issues, Feel free to ask for support. You can send mail to [email protected] you can ping me on my Facebook page https://www.facebook.com/seleniumexpress Make sure to join my private Facebook page (Ask me here) “SeleniumExpress - Support" https://www.facebook.com/groups/187000222361579/ you can ask for support in my website forum https://www.seleniumexpress.com Subscribe to my youtube channel Follow me on Insta https://www.instagram.com/selenium_express/

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