Definition
Cloud computing is the delivery of computing services — including servers, storage, databases, networking, software, analytics, and intelligence — over the internet (“the cloud”) to offer faster innovation, flexible resources, and economies of scale. Instead of owning and maintaining physical data centers and servers, organizations can rent access to anything from applications to storage from a cloud service provider.
Core characteristics
Cloud computing is defined by a few key characteristics that make it different from traditional IT:
- On-demand self-service: Users can provision resources as needed without human interaction with the provider.
- Broad network access: Services are available over the network and accessed through standard mechanisms (web, mobile, APIs).
- Resource pooling: Provider resources serve multiple consumers using a multi-tenant model, with resources dynamically assigned and reassigned.
- Rapid elasticity: Resources can be elastically scaled up or down to meet demand.
- Measured service: Resource usage is monitored, controlled, and reported for transparency and billing.
Primary service models
Understanding the service models helps choose the right level of control and responsibility:
- IaaS (Infrastructure as a Service): Provides virtualized computing resources over the internet. Example: virtual machines, block storage, and networking. (Best when you need control over OS and middleware.)
- PaaS (Platform as a Service): Provides a platform allowing customers to develop, run, and manage applications without dealing with infrastructure. Example: managed application runtimes and databases.
- SaaS (Software as a Service): Delivers software applications over the internet on a subscription basis. Example: email, CRM, and collaboration tools.
Deployment models
Different deployment models address security, privacy, and compliance needs:
- Public cloud: Services offered over the public internet and shared across organizations. Providers: AWS, Azure, Google Cloud.
- Private cloud: Cloud infrastructure operated solely for a single organization (on-premises or hosted) offering greater control and isolation.
- Hybrid cloud: Combination of private and public clouds with orchestration between them to allow data and application portability.
- Multi-cloud: Use of multiple cloud services from different providers to reduce vendor lock-in or optimize costs/features.
Benefits
Adopting cloud computing delivers several measurable benefits:
- Cost efficiency: Lower capital expenditure; pay-as-you-go pricing.
- Scalability & performance: Rapidly scale resources to match demand.
- Speed & agility: Faster time-to-market for new services and experiments.
- Reliability: Built-in redundancy and high availability from providers.
- Global reach: Deploy services in multiple regions and zones for latency and compliance needs.
Common use cases
Cloud computing powers many modern workloads:
- Web and mobile applications
- Data analytics and machine learning
- DevOps and continuous integration/continuous delivery (CI/CD)
- Backup, disaster recovery, and archiving
- IoT, streaming, and event-driven architectures
Shared responsibility model (short note)
Cloud providers and customers share security responsibilities. Providers secure the physical infrastructure and foundational services; customers are typically responsible for data, access controls, and application-level security. The exact split varies by service model (IaaS vs PaaS vs SaaS).
Quick example (JSON snippet)
{
"service": "SaaS",
"example": "Salesforce",
"benefit": "No infrastructure to manage, subscription-based"
}
Summary
Cloud computing is a transformative IT delivery model that enables organizations to consume compute and storage resources as services. It improves agility, reduces costs, and supports modern application patterns — but it also introduces new operational, governance, and security considerations that teams must manage.