हिंदी में: क्लाउड कंप्यूटिंग — इंटरनेट पर किराए के सर्वर, स्टोरेज और सर्विस, जितना इस्तेमाल उतना भुगतान।
What is cloud computing?
Cloud computing is the on-demand delivery of computing resources — servers, storage, databases, networking and software — over the internet, with pay-as-you-go pricing. Instead of buying and maintaining hardware, you rent what you need and scale it up or down.
Key characteristics (NIST)
- On-demand self-service – provision resources yourself, any time.
- Broad network access – available over the network from many devices.
- Resource pooling – providers serve many customers from shared hardware.
- Rapid elasticity – scale quickly with demand.
- Measured service – usage is metered and billed.
Service models
| Model | You manage | Provider manages | Examples |
|---|---|---|---|
| IaaS – Infrastructure as a Service | OS, runtime, apps, data | Hardware, virtualization, network | AWS EC2, Azure Virtual Machines, Google Compute Engine |
| PaaS – Platform as a Service | Apps and data | Everything below the app | Google App Engine, Azure App Service, Heroku |
| SaaS – Software as a Service | Just your use and data | Everything | Gmail, Microsoft 365, Google Docs |
Newer models include FaaS / serverless (AWS Lambda, Azure Functions, Google Cloud Functions), where you upload functions and pay only when they run.
Deployment models
- Public cloud – shared infrastructure owned by a provider.
- Private cloud – dedicated to one organisation.
- Hybrid cloud – a mix of public and private, connected together.
- Community cloud – shared by organisations with common requirements.
- Multi-cloud – using services from more than one provider.
Virtualization and containers
Virtualization lets one physical server run many virtual machines (VMs) through a hypervisor. – Type 1 (bare-metal): VMware ESXi, Microsoft Hyper-V, KVM. – Type 2 (hosted): VirtualBox, VMware Workstation.
Containers (Docker) package an application with its dependencies and share the host OS kernel, so they start in seconds and use fewer resources than VMs. Kubernetes orchestrates containers: scheduling, scaling, self-healing and rolling updates.
| Virtual machine | Container | |
|---|---|---|
| Includes | Full guest OS | App + libraries only |
| Start-up | Minutes | Seconds |
| Isolation | Strong | Process-level (lighter) |
| Size | GBs | MBs |
Major cloud providers
Amazon Web Services (AWS), Microsoft Azure and Google Cloud Platform (GCP) are the largest, followed by others such as Oracle Cloud and IBM Cloud. Each offers compute, storage (object, block, file), databases, networking, AI services and monitoring.
Core building blocks
- Compute – virtual machines, containers, serverless functions.
- Storage – object storage (Amazon S3, Azure Blob), block disks, file shares.
- Databases – managed SQL and NoSQL services.
- Networking – virtual private clouds, load balancers, CDNs, DNS.
- Identity – IAM users, roles and policies.
Benefits and challenges
Benefits: no upfront hardware cost, global reach, high availability, automatic scaling, fast experimentation.
Challenges: unexpected bills if resources are left running, vendor lock-in, data-location regulations, internet dependence and the need to configure security correctly.
Shared responsibility for security
The provider secures the cloud itself (data centres, hardware, core network); the customer secures what they put in the cloud (data, access rights, configurations, patches on their VMs). Many cloud breaches come from misconfigured storage buckets or leaked access keys — use least-privilege IAM, MFA and encryption.
Getting started
- Use the free tiers of AWS, Azure or GCP to practise (and set billing alerts).
- Learn Linux basics, networking and one scripting language.
- Try deploying a small web app with a database, then containerise it with Docker.
- Beginner certifications: AWS Certified Cloud Practitioner, Microsoft Azure Fundamentals (AZ-900), Google Cloud Digital Leader.
Quick revision
- IaaS → you manage the OS; PaaS → you manage the app; SaaS → you just use it.
- Containers share the host kernel; VMs have a full guest OS.
- Shared responsibility: provider secures the cloud, you secure what is in it.