☁️ Cloud Computing Service Models – AWS

#aws #cloud

In cloud computing, service models define how resources and services are delivered to users.

The three primary service models are:

1. Infrastructure as a Service (IaaS)

Definition:

Provides virtualized computing resources over the internet. Users can rent servers, storage, and networking infrastructure without owning physical hardware.

Key Features:

Complete control over infrastructure (OS, runtime, apps)
Highly scalable and flexible
Pay-as-you-go pricing
Ideal for sysadmins, DevOps, and IT teams

Examples in AWS:

🖥️ Amazon EC2 – Virtual servers (compute)
💾 Amazon S3 – Object storage
🛜 Amazon VPC – Virtual networking
📦 Amazon EBS – Block storage
🔐 AWS IAM – Access control

✅ Use Case:

Hosting web applications
Running enterprise workloads
Creating testing and development environments

2. Platform as a Service (PaaS)

Definition:

Provides a platform with pre-configured environments for building, testing, and deploying applications without managing underlying infrastructure.

Key Features:

Developers focus on application logic, not infrastructure
Auto-scaling and easy deployment
Integrated development tools and frameworks

Examples in AWS:

🧱 AWS Elastic Beanstalk – Deploy and manage apps easily
🧪 AWS Lambda (serverless) – Run code without managing servers
🗄️ Amazon RDS – Managed relational database service
🔔 Amazon API Gateway – Build and manage APIs

✅ Use Case:

Building scalable web apps quickly
Continuous deployment pipelines
Serverless application development

3. Software as a Service (SaaS)

Definition:

Delivers fully functional software over the internet on a subscription basis. The provider manages everything (infrastructure, platform, app, security).

Key Features:

Ready-to-use applications
No installation or maintenance
Accessible from any device via browser

Examples in AWS:

💻 Amazon WorkMail – Business email service
🧑‍💼 Amazon Chime – Online meetings and communication
📊 Third-party SaaS apps hosted on AWS (e.g., Salesforce, Zoom)

✅ Use Case:

Email services, CRM, collaboration tools
Productivity and business software

🧭 Comparison Table

Feature	IaaS	PaaS	SaaS
Control Level	High (infra & OS)	Medium (app only)	Low (end-user access)
Target User	IT Admin, DevOps	Developers	End Users
Example in AWS	EC2, S3, VPC	Elastic Beanstalk, Lambda, RDS	WorkMail, Chime, Salesforce
Scalability	Manual or auto scaling	Auto-scaling built-in	Provider managed
Maintenance	User-managed	Shared	Provider-managed

🏁 Additional Models (Emerging)

Function as a Service (FaaS) — e.g., AWS Lambda (a part of PaaS but more fine-grained)
Container as a Service (CaaS) — e.g., Amazon ECS and Amazon EKS