Cloud computing is the on-demand delivery of IT resources—including servers, storage, databases, networking, software, and analytics—over the internet via a pay-as-you-go pricing model. Instead of owning and maintaining physical data centres and servers, entities can access technology services from cloud providers on an as-needed basis.
Core Characteristics
Cloud computing is defined by several essential characteristics that differentiate it from traditional IT infrastructure:
- On-demand self-service: Users can provision computing capabilities, such as server time and network storage, automatically without human interaction with the provider.
- Broad network access: Capabilities are available over the network and accessed through standard mechanisms (e.g., mobile phones, tablets, laptops, and workstations).
- Resource pooling: The provider’s computing resources are pooled to serve multiple consumers, with different physical and virtual resources dynamically assigned according to demand.
- Rapid elasticity: Capabilities can be elastically provisioned and released to scale rapidly outward and inward commensurate with demand.
- Measured service: Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and the consumer.
Cloud Service Models
Cloud services are categorized into three primary service models:
| Model | Description | Example |
| Infrastructure as a Service (IaaS) | Provides fundamental computing resources (virtual servers, storage, networks) over the internet. | AWS EC2, Google Compute Engine |
| Platform as a Service (PaaS) | Provides a platform allowing customers to develop, run, and manage applications without the complexity of building the infrastructure. | Google App Engine, Heroku |
| Software as a Service (SaaS) | Delivers software applications over the internet on a subscription basis. | Microsoft 365, Salesforce, Google Workspace |
Deployment Models
The deployment model refers to the environment in which the cloud infrastructure is operated:
- Public Cloud: Owned and operated by third-party cloud service providers, delivering resources over the internet. Highly scalable but shared among multiple users (multi-tenancy).
- Private Cloud: Infrastructure used exclusively by a single organization. It can be physically located at the organization’s on-site data centre or hosted by a third-party service provider.
- Hybrid Cloud: Combines public and private clouds, bound together by technology that allows data and applications to be shared between them. Provides greater flexibility and deployment options.
- Community Cloud: Shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations).
Key Concepts and Terminology
- Multi-tenancy: An architecture where a single instance of a software application serves multiple customers (tenants). Each tenant’s data is isolated and remains invisible to other tenants.
- Virtualization: The creation of a virtual version of a resource, such as a server, desktop, storage device, or network resource. This is the foundational technology that enables cloud computing.
- Latency: The time it takes for data to travel from the source to the destination. Edge computing is often used to reduce latency in cloud environments.
- Serverless Computing: A cloud execution model where the cloud provider runs the server, and dynamically manages the allocation of machine resources. Pricing is based on the actual amount of resources consumed by an application, rather than pre-purchased capacity.
Strategic Importance and Security
Cloud computing is a cornerstone of India’s digital transformation strategy, supporting initiatives like the National E-Governance Plan (NeGP) and Digital India.
- Security Responsibility: Cloud security follows a “Shared Responsibility Model.” The provider is responsible for the security of the cloud (infrastructure, hardware), while the customer is responsible for security in the cloud (data, configurations, access management).
- Data Sovereignty: Cloud providers must comply with local laws regarding where data is stored and processed, a critical concern for government and financial institutions.
- Cost Efficiency: Reduces the Total Cost of Ownership (TCO) by eliminating the capital expenditure of purchasing hardware and the operational expenditure of maintaining physical facilities.
Challenges
- Vendor Lock-in: The difficulty of switching from one cloud provider to another due to proprietary technologies and data compatibility issues.
- Compliance and Regulation: Navigating complex legal frameworks regarding data privacy (e.g., Digital Personal Data Protection Act).
- Network Dependency: Continuous internet connectivity is essential; interruptions can lead to significant service downtime.