What is Cloud Computing?

What is Cloud Computing?

Cloud computing is the on-demand delivery of computing resources — including servers, storage, databases, networking, software, and analytics — over the internet with pay-as-you-go pricing. Instead of buying and maintaining physical hardware, you rent computing resources from a cloud provider like AWS.

The Official Definition

The National Institute of Standards and Technology (NIST) provides the widely accepted definition of cloud computing. According to NIST, cloud computing has five essential characteristics:

1. On-demand self-service — You can provision resources without human interaction with the provider
2. Broad network access — Resources are available over the network and accessed through standard mechanisms
3. Resource pooling — The provider serves multiple customers using a multi-tenant model
4. Rapid elasticity — Resources can be scaled up or down quickly to match demand
5. Measured service — Resource usage is monitored, controlled, and billed transparently

How Cloud Computing Works

Instead of managing physical servers, you interact with cloud resources through a web interface, CLI, or API:

Traditional IT:                    Cloud Computing:
┌──────────────┐                  ┌──────────────────┐
│ You buy       │                  │ Cloud Provider    │
│ servers       │                  │ owns servers      │
│ You manage    │                  │ Provider manages  │
│ everything    │                  │ infrastructure    │
│ You pay       │       →         │ You pay only for  │
│ upfront       │                  │ what you use      │
│ You scale     │                  │ You scale         │
│ manually      │                  │ instantly         │
└──────────────┘                  └──────────────────┘

Cloud Deployment Models

There are three main deployment models for cloud computing:

Public cloud is what most people mean when they say "cloud computing," and it is the primary focus of the CLF-C02 exam.

The Six Advantages of Cloud Computing

AWS identifies six key advantages of cloud computing over traditional IT:

1. Trade capital expense for variable expense — Instead of investing heavily upfront, you pay only for what you consume
2. Benefit from massive economies of scale — Cloud providers aggregate usage from hundreds of thousands of customers, achieving lower costs
3. Stop guessing capacity — Scale your resources up or down based on actual demand
4. Increase speed and agility — Provision new resources in minutes instead of weeks
5. Stop spending money running and maintaining data centers — Focus on your business, not on infrastructure
6. Go global in minutes — Deploy your application in multiple geographic regions with a few clicks

CapEx vs OpEx

Understanding the financial shift is critical for the exam:

Pro Tip: The concept of trading CapEx for OpEx is one of the most frequently tested topics on the CLF-C02 exam. Make sure you understand the financial advantages of cloud computing.

Key Takeaways

• Cloud computing is the on-demand delivery of computing resources over the internet with pay-as-you-go pricing
• NIST defines five essential characteristics: on-demand, broad access, pooling, elasticity, measured service
• Three deployment models: Public, Private, and Hybrid cloud
• AWS identifies six advantages: variable expense, economies of scale, no capacity guessing, speed, no data center management, and global reach
• Cloud computing shifts spending from CapEx (upfront) to OpEx (pay-as-you-go)
• Public cloud is the primary focus of the CLF-C02 exam