> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Core Concepts Section Introduction > This article introduces essential concepts of modern Cluster Architecture, covering key API primitives for managing containerized applications. This article introduces the essential concepts underpinning modern Cluster Architecture. We start with a high-level overview to help you understand how various components form a cohesive structure. Following the overview, the discussion advances to key API primitives—including Pods, ReplicaSets, Deployments, and Services—that are integral to managing containerized applications. If you already have foundational training or have completed certification-level learning for Application Developers, you may opt to bypass some sections and focus solely on the practice tests. Let’s embark on our exploration of Cluster Architecture and uncover how these components interact to deliver a robust deployment environment.