Cloud Computing

Cloud computing is the delivery of computing services—like servers, storage, databases, networking, and software—over the internet on an on‑demand, pay‑as‑you‑go basis. Instead of buying and maintaining physical data centers and servers, users rent these resources from cloud providers such as AWS, Azure, or Google Cloud and scale them up or down as needed.

Core idea

• Cloud computing lets organizations access pooled computing resources hosted in remote data centers, often called “the cloud,” via the internet.

• Users pay primarily for what they consume, which helps reduce capital expenditure and converts it into operating expense.

Key characteristics

• On‑demand self‑service: Users can provision computing resources (like VMs or storage) automatically without human interaction with the provider.

• Scalability and elasticity: Resources can scale quickly up or down with demand; to users, capacity often appears virtually unlimited.

• Broad network access: Services are available over the network and accessed through standard devices such as laptops, phones, and tablets.

• Measured service: Usage is monitored and metered, enabling pay‑as‑you‑go pricing models.

Service models

• IaaS (Infrastructure as a Service): Provides virtualized compute, storage, and networking (for example, EC2, virtual machines, VPC); users manage OS and above.

• PaaS (Platform as a Service): Offers a managed platform to build, run, and deploy applications without managing underlying servers (for example, Azure App Service, Google App Engine).

• SaaS (Software as a Service): Delivers complete applications over the internet (for example, Office 365, Salesforce, Google Workspace), managed entirely by the provider.

Deployment models

• Public cloud: Infrastructure is owned and operated by a provider and shared among multiple customers in a multi‑tenant model.

• Private cloud: Cloud infrastructure dedicated to a single organization, either on‑premises or hosted by a third party, with more control and customization.

• Hybrid cloud: Combines public and private clouds, allowing data and applications to move between them for flexibility and optimization.

• Multi‑cloud: Use of services from multiple public cloud providers to avoid lock‑in or leverage specific strengths.

Benefits

• Lower upfront cost, faster time to market, global reach, high availability, and offloading of hardware and many security responsibilities to specialized providers.

Common examples

• Storing files in Google Drive or iCloud instead of local disks.

• Streaming services like Netflix that rely on cloud infrastructure for content delivery and scaling.

• Enterprises running their web apps, databases, and analytics workloads on AWS, Azure, or Google Cloud instead of their own data centers.