Amazon Web Services (AWS) is the world’s most widely adopted cloud platform, offering 200+ fully featured services across compute, storage, databases, networking, analytics, machine learning, and security. Whether you are migrating a legacy monolith or building a greenfield serverless API, AWS provides the building blocks.

What is Cloud Computing?

Cloud computing delivers IT resources over the internet on a pay-as-you-go basis. Instead of buying and maintaining physical servers, you rent capacity from AWS data centers and scale up or down in minutes.

Traditional Cloud (AWS)
CapEx — buy hardware upfront OpEx — pay monthly for what you use
Weeks to provision servers Minutes to launch instances
Over-provision for peak load Auto Scaling matches demand
Single data center Global regions and edge locations

AWS Global Infrastructure

Understanding regions and availability zones (AZs) is foundational:

  • Region — a geographic area (e.g., us-east-1, eu-west-1). Choose based on latency, compliance, and service availability.
  • Availability Zone — one or more discrete data centers within a region, connected by low-latency networking. Deploy across multiple AZs for high availability.
  • Edge Locations — used by CloudFront CDN to cache content closer to users.
  # List available regions
aws ec2 describe-regions --query 'Regions[*].RegionName' --output table

# Check your current default region
aws configure get region

Core Service Categories

Category Key Services Typical Use Case
Compute EC2, Lambda, ECS, EKS Run applications and workloads
Storage S3, EBS, EFS, Glacier Files, backups, static assets
Database RDS, DynamoDB, Aurora, ElastiCache Structured and NoSQL data
Networking VPC, Route 53, CloudFront, ALB Isolation, DNS, CDN, load balancing
Security IAM, KMS, WAF, GuardDuty Identity, encryption, threat detection
DevOps CodePipeline, CloudFormation, ECS CI/CD and infrastructure as code

The Shared Responsibility Model

AWS secures the cloud (hardware, hypervisor, physical data centers). You secure in the cloud (OS patches, network rules, application code, data encryption).

AWS Responsibility Your Responsibility
Physical security of data centers IAM policies and MFA
Hypervisor and host infrastructure Security groups and NACLs
Managed service patching (RDS, Lambda) Application vulnerabilities
Global network infrastructure Data classification and encryption

Real-World Scenario: Startup Web App

A typical three-tier architecture on AWS:

  1. Route 53 — DNS pointing to your domain
  2. CloudFront + S3 — static frontend assets
  3. Application Load Balancer — distributes traffic to EC2 or ECS
  4. RDS PostgreSQL — managed database in private subnets
  5. CloudWatch — metrics, logs, and alarms

This pattern scales from a single t3.micro to thousands of instances without redesigning the architecture.

Getting Started Checklist

  1. Create an AWS account at aws.amazon.com
  2. Enable MFA on the root account immediately
  3. Create an IAM admin user — never use root for daily work
  4. Set up billing alerts in AWS Budgets (alert at 50%, 80%, 100%)
  5. Install the AWS CLI and configure credentials
  6. Explore the AWS Free Tier — 12 months of limited free usage on many services
  # Verify your identity after CLI setup
aws sts get-caller-identity

# Expected output:
# {
#     "UserId": "AIDAXXXXXXXXXXXXXXXX",
#     "Account": "123456789012",
#     "Arn": "arn:aws:iam::123456789012:user/admin"
# }

AWS vs Azure vs GCP (Quick Comparison)

Feature AWS Azure GCP
Market share Largest Second Third, strong in data/ML
Compute VM EC2 Virtual Machines Compute Engine
Serverless Lambda Azure Functions Cloud Functions
Object storage S3 Blob Storage Cloud Storage
Managed K8s EKS AKS GKE
Identity IAM Azure AD / Entra ID Cloud IAM

Common Mistakes for Beginners

  1. Using the root account for development — create IAM users with least privilege instead.
  2. Ignoring region selection — data residency and latency matter; some services are region-specific.
  3. No billing alerts — a misconfigured Auto Scaling group can generate surprise bills.
  4. Public S3 buckets — default since 2023 blocks public access, but verify bucket policies.
  5. Single AZ deployments — production workloads should span at least two availability zones.

Best Practices from Day One

  • Tag all resources (Environment, Project, Owner) for cost allocation
  • Use AWS Organizations for multi-account strategies in production
  • Enable CloudTrail in all regions for audit logging
  • Prefer managed services (RDS over self-managed MySQL on EC2) unless you have a specific reason
  • Document your architecture with diagrams — AWS Architecture Icons are free to use

Troubleshooting Tips

Problem Likely Cause Fix
“Access Denied” on CLI Missing IAM permissions or wrong profile Check aws sts get-caller-identity and attached policies
Service not available in region Regional service launch Switch region or check AWS Regional Services
Unexpected charges Idle resources (EIPs, EBS volumes) Use Cost Explorer and AWS Trusted Advisor

This track takes you from account setup through production architecture. Next: AWS Account Setup.