Introduction to Cloud Computing
Quick‑reference guide for students, professionals, and anyone new to the cloud.
1. What Is Cloud Computing?
| Aspect |
Definition |
| Core idea |
Deliver computing resources (servers, storage, databases, networking, software, analytics, AI) over the Internet on a pay‑as‑you-go basis. |
| Key benefit |
Users can access powerful IT capabilities without owning or managing physical hardware. |
| Analogy |
Like electricity: you plug in a device and pay for the kilowatt‑hours you consume, rather than building your own power plant. |
2. Service Models (What You Consume)
| Model |
What It Provides |
Typical Use Cases |
| IaaS – Infrastructure as a Service |
Virtualized compute, storage, and networking (e.g., VMs, block storage, load balancers). |
Run custom OSes, legacy apps, large data‑processing clusters. |
| PaaS – Platform as a Service |
Runtime environment, middleware, development tools, managed databases. |
Build, test, and deploy web/mobile apps without worrying about OS patches or scaling. |
| SaaS – Software as a Service |
Fully functional applications delivered via a web browser or API. |
Email (Gmail), CRM (Salesforce), collaboration (Microsoft 365), analytics dashboards. |
| FaaS / Serverless (often grouped under PaaS) |
Event‑driven functions that run only when triggered. |
Micro‑services, data pipelines, IoT processing. |
3. Deployment Models (Where You Run It)
| Model |
Description |
When to Choose |
| Public Cloud |
Resources owned and operated by a third‑party provider; shared among many customers. |
Start‑ups, variable workloads, need for rapid scaling. |
| Private Cloud |
Dedicated infrastructure (on‑premises or hosted) for a single organization. |
Strict regulatory/compliance requirements, legacy workloads. |
| Hybrid Cloud |
Combination of public and private clouds with orchestration between them. |
Burst workloads to public cloud, keep sensitive data on‑premises. |
| Multi‑Cloud |
Use of two or more public cloud providers simultaneously. |
Avoid vendor lock‑in, leverage best‑of‑breed services (e.g., AI from one, storage from another). |
4. Core Characteristics (Why It Works)
| Characteristic |
Explanation |
| On‑Demand Self‑Service |
Users can provision resources via a portal or API instantly. |
| Broad Network Access |
Access from any device with Internet connectivity (laptops, smartphones, IoT). |
| Resource Pooling |
Multi‑tenant architecture; physical resources are abstracted and shared. |
| Rapid Elasticity |
Scale out/in automatically based on demand; resources appear limitless. |
| Measured Service |
Usage is monitored, billed, and reported (CPU hours, GB‑months, API calls). |
5. Major Cloud Providers (Quick Overview)
| Provider |
Notable Services |
Unique Strength |
| Amazon Web Services (AWS) |
EC2, S3, Lambda, RDS, SageMaker |
Largest ecosystem, deep service breadth. |
| Microsoft Azure |
Virtual Machines, Azure SQL, Functions, Azure AI |
Strong integration with Windows/Office, hybrid tools (Azure Arc). |
| Google Cloud Platform (GCP) |
Compute Engine, Cloud Storage, BigQuery, Vertex AI |
Advanced data |