This topic will cover the basics of cloud computing, including its definition, key characteristics, benefits, and different service models such as SaaS, PaaS, and IaaS.
Introduction to Cloud Computing
Prepared as concise, easy‑to‑read study notes
1. What Is Cloud Computing?
| Definition |
Key Idea |
| Delivery of computing services (servers, storage, databases, networking, software, analytics, AI, etc.) over the Internet “the cloud.” |
Users access resources on‑demand, pay only for what they use, and avoid managing physical hardware. |
2. Core Characteristics (NIST Definition)
| Characteristic |
What It Means for Users |
| On‑Demand Self‑Service |
Provision resources (e.g., VMs, storage) automatically via a portal or API without human interaction. |
| Broad Network Access |
Services reachable from any device (laptop, phone, tablet) over standard networks (Internet, VPN). |
| Resource Pooling |
Multi‑tenant model – physical and virtual resources are shared among many customers, dynamically allocated. |
| Rapid Elasticity |
Scale out/in quickly (seconds to minutes) to match workload spikes or drops. |
| Measured Service |
Usage is monitored, reported, and billed (pay‑as‑you‑go). |
3. Service Models
| Model |
Description |
Typical Use Cases |
| IaaS – Infrastructure as a Service |
Provides virtualized compute, storage, networking. Users manage OS, middleware, runtime, data, applications. |
Hosting websites, disaster‑recovery, big‑data processing clusters. |
| PaaS – Platform as a Service |
Supplies runtime environment, development tools, database services. Users focus on code and data. |
Rapid app development, API services, CI/CD pipelines. |
| SaaS – Software as a Service |
Fully managed applications delivered over the web. Users only interact with the UI. |
Email (e.g., Gmail), CRM (Salesforce), collaboration (Office 365). |
| FaaS / Serverless (often considered a subset of PaaS) |
Executes individual functions in response to events; no server management. |
Event‑driven processing, micro‑services, IoT data handling. |
4. Deployment Models
| Model |
Ownership |
Accessibility |
Typical Scenarios |
| Public Cloud |
Cloud provider owns & operates the infrastructure. |
Available to anyone over the Internet (multi‑tenant). |
Start‑ups, variable workloads, global reach. |
| Private Cloud |
Dedicated to a single organization (on‑premises or hosted). |
Access limited to that organization (single‑tenant). |
Regulated industries, legacy migration, data sovereignty. |
| Hybrid Cloud |
Combination of public & private clouds, linked by orchestration. |
Workloads can move between environments. |
Bursting to public cloud, separating sensitive data, phased migration. |
| Community Cloud |
Shared by several organizations with common concerns (e.g., government, research). |
Managed jointly or by a third party. |
Collaborative projects, industry‑specific compliance. |
5. Major Cloud Providers (2024)
| Provider |
Core Offerings |
Notable Services |
| Amazon Web Services (AWS) |
IaaS, PaaS, SaaS, Serverless |
EC2, S3, Lambda, RDS, SageMaker |
| Microsoft Azure |
Integrated with Windows ecosystem |
Virtual Machines, Azure Functions, Cosmos DB, Azure AI |
| Google Cloud Platform (GCP) |
Data‑analytics & AI focus |
Compute Engine, Cloud Storage, BigQuery, Cloud Run |
| IBM Cloud, **Oracle Cloud |
|
|