Complete Kubernetes Course Notes

Introduction

• Speaker: Sid from DevOps Directive
• Purpose: A complete course to teach Kubernetes to software engineers wanting to enhance their DevOps and infrastructure skills.

Course Structure

• Duration: A few hours.
• Levels: From beginner to pro.
• Components:
  • Video lectures
  • Companion GitHub repo with code samples
  • Written modules available online
  • Discord community for interaction and Q&A
• Time invested: 150 hours
• Course offered free of charge for accessibility.

Prerequisites

1. Familiarity with web applications (JavaScript, Go, Python).
2. Basic shell commands and comfort with Linux shell.
3. Basic cloud infrastructure knowledge.
4. Intermediate containerization knowledge (Docker).

Course Sections Overview

Section 1: Theory

• Motivation and history behind Kubernetes
• Overview of Kubernetes architecture and components
• Setting up development environment with tools and dependencies
• Provisioning local and cloud clusters
• Built-in Kubernetes resource types and introduction to Helm.

Section 2: Hands-On

• Deploying a demo application on Kubernetes
• Extending built-in resources with custom resources
• Enhancing developer experience in Kubernetes
• Debugging broken applications
• Deploying to multiple environments

Kubernetes History

• 2000s:

  • On-premises deployments, system administrators managing servers.
  • Challenges with microservices architecture.

• 2010s:

  • Emergence of cloud infrastructure, VMs created/destroyed rapidly.
  • Introduction of configuration management tools (Puppet, Chef).
  • Challenges of managing cloud resources.

• Recent Years:

  • Containers becoming standard, orchestrators like Kubernetes for management.
  • Features include efficient scheduling, health checks, service discovery, scaling, and storage provisioning.

Kubernetes Architecture

• Key Terms: Cluster, Node, Control Plane, Data Plane.
• System Components:
  • Cloud Controller Manager: Interfaces with cloud provider for resources (e.g., load balancers).
  • Controller Manager: Regulates cluster state.
  • Kubernetes API: Main interface for interacting with Kubernetes.
  • etcd: Data store for managing cluster resources.
  • Scheduler: Decides which nodes will run pods.

Custom Resources and Controllers

• Custom Resource Definitions (CRDs): Extend Kubernetes API with new resource types.
• Example projects: Cloud native PG for PostgreSQL, cert-manager for TLS management, Crossplane for infrastructure as code.

Deploying Applications with Helm

• Helm: Package manager for Kubernetes applications.
• Structure of Helm charts: metadata, templates, values.yaml.
• Helm commands: install, upgrade, rollback, template, package, push.
• Example: Using Helm to deploy PostgreSQL and other services.

Continuous Integration & Delivery

• CI with GitHub Actions: Testing, building, and pushing container images.
• CD with GitOps: Syncing Git repository to Kubernetes cluster.
• Tools: Tilt for local development, GitOps tools like Argo CD, Flux, and Clue Control.

Debugging Applications

• Tools for debugging: K9s, kubectl logs, describe, port forward, etc.
• Example: Deploying a broken microservices demo and troubleshooting issues.

Managing Secrets

• Challenges in secret management: avoiding storing secrets in version control.
• Approaches: External Secrets Operator, Sops, sealed secrets, using cloud secret managers.

Upgrading Kubernetes Clusters

• Upgrade procedure: Check for deprecated APIs, upgrade control plane, then worker nodes.
• Recommended method: Create new node pool with the updated version and migrate workloads.

Conclusion

• Course summary: Building a foundational knowledge of Kubernetes, deploying and managing applications, and automation practices with CI/CD and GitOps.

Next Steps

• Explore networking topics, resource optimization, disaster recovery, operator building, and other advanced features.