Infrastructure as a Service (IaaS)
IaaS is a cloud computing model where a provider hosts virtualized computing resources over the internet.
Tiers: Cloud Infrastructure (IaaS) -> Development Platform (PaaS) -> Software App (SaaS). Examples: AWS EC2, Azure VMs, Google Compute Engine, DigitalOcean Droplets.
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🧒 Explain Like I'm 5
IaaS is like renting a Lego kit instead of buying the whole store. You can build whatever you want, whenever you want, and you only pay for the pieces you are using. When you're done, you give them back and stop paying.
🤓 Expert Deep Dive
Technically, IaaS is built on 'Hardware Virtualization' (Hypervisors like Xen, KVM, or Hyper-V). It exposes resources via RESTful APIs, allowing for 'Infrastructure as Code' (IaC) using tools like Terraform. The critical advantage is 'Elasticity'—the ability to dynamically allocate resources based on load. However, this introduces complexity in 'Networking Virtualization', requiring users to manage Subnets, Routing Tables, and Security Groups in a software-defined environment. Unlike PaaS, IaaS offers the highest level of control but requires the most maintenance from the user's DevOps team.