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MODULE 2 - Kubernetes Architecture and Components

Overview​

This module dives deep into the internal architecture of Kubernetes. You will discover how the Control Plane and Worker Node components actually work, their interactions, and how they work together to orchestrate your applications.

Learning Objectives​

By the end of this module, you will be able to:

  • Understand the role and operation of each Control Plane component
  • Identify Worker Node components and their responsibilities
  • Visualize the communication flows between components
  • Inspect and monitor system components
  • Understand how Kubernetes makes decisions

Estimated Duration​

Theory: 4-5 hours
Practice: 3-4 hours
Total: 7-9 hours

Table of Contents​

Part 1: Control Plane​

  1. Chapter 2.1 - Architecture Overview
  2. Chapter 2.2 - API Server
  3. Chapter 2.3 - etcd
  4. Chapter 2.4 - Controller Manager
  5. Chapter 2.5 - Scheduler

Part 2: Worker Nodes​

  1. Chapter 2.6 - kubelet
  2. Chapter 2.7 - kube-proxy
  3. Chapter 2.8 - Container Runtime

Part 3: Communication and Add-ons​

  1. Chapter 2.9 - Inter-Component Communication
  2. Chapter 2.10 - Add-ons and Extensions

Hands-on Labs​

Validation​

Kubernetes Architecture: Overview​

A Kubernetes cluster is composed of two main types of machines:

Control Plane (Master)​

The Control Plane is the brain of the cluster. It makes all decisions and maintains the desired state.

Components:

  • API Server: Single entry point, exposes the REST API
  • etcd: Distributed database, stores the cluster state
  • Controller Manager: Runs controllers that maintain the desired state
  • Scheduler: Assigns Pods to nodes

Worker Nodes​

Worker Nodes run the applications (Pods).

Components:

  • kubelet: Agent that manages Pods on the node
  • kube-proxy: Manages networking and load balancing
  • Container Runtime: Runs the containers (Docker, containerd, etc.)

Why Understand the Architecture?​

Understanding the internal architecture allows you to:

  • Debug effectively: Know where to look when something is not working
  • Optimize performance: Understand potential bottlenecks
  • Plan capacity: Know which components require more resources
  • Secure the cluster: Understand entry points and communications
  • Troubleshoot: Quickly identify the source of problems

Next Steps​

Now that you have an overview, dive into the details:

Chapter 2.1: Architecture Overview
Chapter 2.2: API Server - The Entry Point

Module created: December 2024