DevOps Overview

DevOps combines development (Dev) and operations (Ops) to shorten the development lifecycle and provide continuous delivery with high software quality.

Core DevOps Practices

Infrastructure as Code (IaC)

Managing and provisioning infrastructure through machine-readable definition files rather than physical hardware configuration or interactive configuration tools.

Key Tools: Terraform, Ansible, CloudFormation, Pulumi

Containerization

Packaging applications with all their dependencies into standardized units called containers.

Key Tools: Docker, Podman, BuildKit

Container Orchestration

Managing containerized workloads and services, including deployment, scaling, and networking.

Key Tools: Kubernetes, Docker Swarm, Nomad

Continuous Integration/Continuous Deployment (CI/CD)

Automatically building, testing, and deploying code changes to production.

Key Tools: GitHub Actions, GitLab CI, Jenkins, ArgoCD

Monitoring & Observability

Collecting metrics, logs, and traces to understand system behavior and performance.

Key Tools: Prometheus, Grafana, ELK Stack, Loki

Tool Selection Guide

Category	Tool	When to Use	Best For
Container Runtime	Docker	Standard container platform	Development, small deployments
	Podman	Rootless containers needed	Security-focused environments
Orchestration	Kubernetes	Complex microservices	Large-scale deployments
	Docker Compose	Multi-container apps	Development, simple deployments
IaC	Terraform	Multi-cloud infrastructure	Managing cloud resources
	Ansible	Configuration management	Server provisioning
	Chef	Configuration management	Infrastructure automation
	Puppet	Configuration management	Infrastructure automation
CI/CD	GitHub Actions	GitHub-based projects	Open source, GitHub workflows
	Jenkins	Self-hosted CI/CD	On-premise, custom pipelines
	ArgoCD	GitOps workflows	Kubernetes deployments

Learning Path

1. Foundations

   • Linux command line basics
   • Networking fundamentals
   • Version control with Git

2. Containerization

   • Start with Docker for container basics
   • Learn Docker Compose for multi-container apps
   • Understand container networking and volumes

3. Orchestration

   • Learn Kubernetes basics (pods, deployments, services)
   • Practice with Helm for package management
   • Understand Kubernetes networking and storage

4. Infrastructure as Code

   • Start with Terraform for cloud resources
   • Learn Ansible for server configuration
   • Practice GitOps workflows with ArgoCD

5. CI/CD

   • Build simple pipelines with GitHub Actions
   • Learn Jenkins for enterprise workflows
   • Implement GitOps with ArgoCD

6. Monitoring

   • Set up Prometheus for metrics collection
   • Create dashboards in Grafana
   • Implement logging with ELK or Loki

Common Scenarios

Scenario: Local Development

Tools: Docker, Docker Compose Use Case: Running application stack locally with database and caching

Scenario: Small Team Deployment

Tools: Docker, Docker Compose, GitHub Actions Use Case: Deploying to single server or small cloud instance

Scenario: Large Microservices Architecture

Tools: Kubernetes, Helm, ArgoCD, Prometheus, Grafana Use Case: Managing dozens of services across multiple environments

Scenario: Multi-Cloud Infrastructure

Tools: Terraform, Ansible, Jenkins Use Case: Managing resources across AWS, Azure, and GCP

Key Concepts

Immutable Infrastructure

Servers are never modified after deployment. New versions are built and deployed, replacing old servers.

Declarative vs Imperative

• Declarative: Define desired state (Terraform, Kubernetes)
• Imperative: Define steps to achieve state (Ansible playbooks)

Blue-Green Deployment

Two identical production environments. Traffic switches between them during deployment.

Canary Deployment

Gradually roll out new version to small subset of users before full deployment.

Infrastructure as Code Principles

• Idempotency: Running same code multiple times produces same result
• Reproducibility: Infrastructure can be recreated identically
• Version Control: All infrastructure changes tracked in Git

Further Reading

• IaC Concepts - Infrastructure as Code patterns and best practices
• Containerization Concepts - Container fundamentals
• CI/CD Concepts - Pipeline patterns and workflows
• Monitoring Concepts - Observability and alerting strategies