Key takeaways
- Cloud computing means renting computing resources — servers, storage, databases, software — over the internet instead of owning them.
- The three main service models are IaaS, PaaS and SaaS; serverless is a popular newer model.
- Key benefits are flexibility, scalability and pay-as-you-go pricing; key risks are cost control and misconfiguration.
- Cloud skills are in demand across IT, development, data and security roles.
Whenever you stream a film, back up photos to your phone's online storage or use a web-based email account, you are using cloud computing. Behind the scenes, huge data centres run the software and store the data, and you access it over the internet.
For businesses, the cloud has transformed how technology is bought and built. This guide explains what cloud computing is, how it works, the main service and deployment models, and why cloud skills are so valuable.
What is cloud computing?
Cloud computing is the on-demand delivery of computing resources — such as servers, storage, databases, networking and software — over the internet, typically with pay-as-you-go pricing.
Instead of buying and maintaining physical servers in their own building, organisations rent capacity from a cloud provider. They can start new servers in minutes, scale up when demand rises and scale down when it falls, paying only for what they use.
A useful analogy: running your own data centre is like generating your own electricity. Using the cloud is like plugging into the power grid and paying for what you consume.
How does cloud computing work?
Cloud providers operate large data centres in regions around the world. Using virtualisation, they divide powerful physical machines into many isolated virtual machines and services that customers can rent. Customers manage their resources through a web console, command-line tools or code, and the provider handles the physical hardware, power, cooling and much of the maintenance.
Resources are organised into regions (geographic areas) and availability zones (separate data centres within a region). Spreading applications across zones helps them keep running even if one facility has a problem.
Cloud service models: IaaS, PaaS, SaaS and serverless
| Model | What you get | You manage | Examples of use |
|---|---|---|---|
| IaaS (Infrastructure as a Service) | Virtual machines, storage and networks | Operating system, runtime, apps and data | Hosting custom servers, lifting existing apps to the cloud |
| PaaS (Platform as a Service) | A managed platform to run your code | Your application and data | Deploying web apps without managing servers |
| SaaS (Software as a Service) | Complete applications | Your data and settings | Web email, office suites, CRM tools |
| Serverless / FaaS | Run functions in response to events | Just your code | APIs, automation, processing uploads |
As you move from IaaS to SaaS, the provider manages more and you manage less. This is captured in the shared responsibility model: the provider secures the underlying infrastructure, while you remain responsible for things like your data, user access and configuration.
Cloud deployment models
- Public cloud: resources are owned and operated by a provider and shared across many customers, each isolated from the others.
- Private cloud: cloud infrastructure dedicated to a single organisation, either on its own premises or hosted.
- Hybrid cloud: a combination of on-premises or private infrastructure and public cloud, connected together.
- Multi-cloud: using services from more than one public cloud provider.
Recommended free courseCloud Computing Foundations: AWS, Azure and Google Cloud View course Benefits of cloud computing
- Speed: new resources are available in minutes rather than weeks.
- Scalability: capacity grows and shrinks automatically with demand.
- Cost model: pay for what you use instead of large upfront hardware purchases.
- Global reach: deploy applications close to users around the world.
- Reliability: built-in options for backups, redundancy and disaster recovery.
- Innovation: instant access to managed databases, analytics and AI services.
Challenges and risks
- Cost control: pay-as-you-go can become expensive if resources are left running or poorly sized. Budgets and alerts are essential.
- Security misconfiguration: many cloud incidents are caused by customer mistakes, such as publicly exposed storage or overly broad permissions.
- Vendor lock-in: relying heavily on one provider's proprietary services can make switching difficult.
- Compliance: some industries and countries have rules about where data may be stored.
Tip: when you create your first cloud account, enable multi-factor authentication and set a billing alert before doing anything else.
The major cloud providers
The three largest public cloud providers are Amazon Web Services (AWS), Microsoft Azure and Google Cloud. They offer similar core services with different strengths. Our detailed comparison, AWS vs Azure vs Google Cloud, helps you decide which to learn first.
Cloud computing careers
Cloud skills are useful in almost every technology role. Common cloud-focused jobs include cloud support associate, cloud engineer, solutions architect, DevOps engineer and cloud security engineer. Developers and data professionals also benefit greatly from knowing how to deploy and scale their work in the cloud. Once you know the basics, learning containers is a natural next step — see Docker vs Kubernetes.
How to start learning cloud computing
- Learn the core concepts: virtual machines, storage, networking, identity and pricing.
- Create a free-tier account with one provider and set a billing alert.
- Launch a virtual machine, host a static website and create a small database.
- Try a serverless function and learn basic infrastructure as code.
- Consider a foundational certification to structure your learning.
Conclusion
Cloud computing lets organisations rent the technology they need, when they need it, instead of owning and maintaining it themselves. Understanding the service models, deployment models, benefits and risks gives you a strong foundation for almost any modern tech career. Start with the basics, practise on a free tier and build from there.
Frequently asked questions
What is cloud computing in simple words?
Cloud computing means renting computing resources such as servers, storage, databases and software over the internet instead of buying and running them yourself, usually paying only for what you use.
What are IaaS, PaaS and SaaS?
IaaS provides virtual infrastructure such as servers and storage, PaaS provides a managed platform for running your code, and SaaS provides complete applications that you use over the internet.
Is the cloud secure?
Major cloud providers invest heavily in security, but customers are responsible for configuring their own resources securely. Many cloud incidents come from misconfigurations such as public storage or weak access controls.
Is cloud computing a good career?
Yes. Cloud skills are in demand across IT operations, software development, data engineering and cybersecurity, and roles such as cloud engineer and DevOps engineer are widely advertised.
