Cover image for Day 1: Understanding Cloud Computing — Service and Deployment Models Explained with a Biryani Analogy

Soumyaranjan Palatasingh

Yesterday I announced I'm blogging daily on AWS & DevOps. Here's Day 1 — the fundamentals everything else builds on.

## What is Cloud Computing?

  • Instead of setting up and maintaining infrastructure on-premises, you now access computing resources remotely over the internet — this is Cloud Computing.

  • "Cloud" refers to a network that provides resources over the internet, accessible whenever needed. It evolved from grid computing, virtualization, and distributed computing. All you need to use it is a web browser.

  • As per NIST, cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (networks, servers, storage, applications, services) that can be rapidly provisioned and released with minimal management effort.

  • Key characteristics: uses virtualization, enables on-demand access, and offers "pay-as-you-use" pricing.

  • Traditional companies had to spend heavily on infrastructure, hardware, and operations. With cloud computing, providers manage all of this — handling troubleshooting, recording activity, and sending analytics data to users.

Service Models — IaaS, PaaS, SaaS

IaaS :

  • Providers offer databases, servers, storage, and networking as a service, and you pay per use.
  • Examples: AWS, Azure, GCP.

PaaS :

  • Gives you an on-demand environment for developing, testing, and delivering apps, with ready dev tools already set up.
  • Examples: Heroku, Google App Engine.

SaaS :

  • Delivers ready-to-use software over the internet, usually via subscription, with the provider managing everything underneath. - Examples: Gmail, Microsoft 365, Google Drive.

The layered view:

  • moving from On-Premise to IaaS to PaaS to SaaS, each model hands you a bigger pre-managed slice.
  • On-premise means you manage everything yourself.
  • IaaS shifts virtualization, servers, storage, and networking to the vendor.
  • PaaS additionally hands over OS, middleware, and runtime.
  • SaaS means the vendor manages everything — you just use the app.

The biryani analogy:

  • IaaS is buying raw ingredients and cooking the biryani yourself.
  • PaaS is eating at a restaurant — it's already cooked, you just show up and eat.
  • SaaS is ordering through Swiggy or Zomato — it arrives fully ready, zero effort.

Deployment Models — Public, Private, Hybrid, Community

Public Cloud :

  • Available to everyone over the internet, free or pay-per-use. -- Cheap and easy to set up since the provider covers hardware and bandwidth costs.
  • Pros: cost-effective, scalable, flexible.
  • Cons: lower security, less customizable.

Private Cloud :

  • Dedicated to one organization, behind a firewall, for a limited set of people.
  • Pros: good for sensitive data, controlled security.
  • Cons: costly, limited remote access.

Hybrid Cloud :

  • A mix of public and private, giving agility for developing and testing new apps.
  • Pros: scalable, cost-effective.
  • Cons: more maintenance, higher setup cost.

Community Cloud :

  • A shared solution for businesses with common concerns like security and compliance.
  • Pros: flexible, compliance-friendly, controlled configuration. - Cons: shared storage/bandwidth limits, harder shared responsibility.

The biryani analogy:

  • Public cloud is like eating at a public food court — open to anyone, no control over standards.
  • Private cloud is like cooking in your own kitchen — full control, but you bear all the cost.
  • Hybrid cloud is cooking at home daily but ordering out for big events.
  • Community cloud is a shared kitchen for one apartment or complex - a defined group sharing space and rules together.

Coming up on Day 2: Client-server architecture and virtualization — two more networking/infra fundamentals before we head into AWS.