Cloud computing lets you rent computing resources instead of buying and operating your own hardware.

Why cloud exists

Cloud providers let teams create infrastructure on demand.

Benefits:

• Faster provisioning.
• Pay-as-you-go pricing.
• Managed services.
• Global reach.
• Elastic scaling.
• Less physical hardware management.

Cloud does not remove engineering responsibility. It changes what you manage.

AWS account

An AWS account is the boundary for billing, permissions, and resources.

Production systems often use multiple accounts:

• Development.
• Staging.
• Production.
• Security or logging.

This reduces blast radius.

Regions

A Region is a geographic area where AWS has multiple data centers.

Examples:

• us-east-1.
• eu-west-1.
• ap-south-1.

Choose a Region based on latency, service availability, compliance, and cost.

Availability Zones

An Availability Zone is one or more isolated data centers inside a Region.

Deploying across multiple Availability Zones improves availability because one zone can fail without taking down the whole system.

Edge locations

Edge locations are used by services like CloudFront to cache content closer to users.

They reduce latency for static assets, downloads, and global delivery.

Backend architecture view

A typical backend may use:

• EC2 or containers for compute.
• RDS for relational data.
• S3 for files.
• VPC for networking.
• IAM for permissions.
• CloudWatch for monitoring.

Quick revision

• Cloud means renting infrastructure and managed services.
• AWS accounts isolate billing and resources.
• Regions are geographic areas.
• Availability Zones improve resilience inside a Region.
• Pick Regions based on latency, compliance, service support, and cost.