IaaS (Infrastructure as a Service) is a cloud service model in which compute, storage, and networking resources are delivered as virtualized or abstracted services, while the physical infrastructure and core platform management are handled by the provider.
IaaS gives clients control over operating systems and applications without requiring them to own or operate physical hardware.
What does IaaS mean in Practice?
In real-world usage, IaaS provides:
- Virtual machines or bare metal instances
- Virtual networks, subnets, and routing
- Block, object, or file storage services
- APIs and control panels for resource management
The provider manages data centers, hardware, and base infrastructure, while the client manages everything above the OS level.
Responsibility Model (Shared Control)
IaaS operates on a shared responsibility model:
- Provider is responsible for:
- Physical data centers
- Servers, storage, and networking hardware
- Power, cooling, and physical security
- Base virtualization or provisioning layer
- Client is responsible for:
- Operating systems
- Applications and services
- Data and backups
- Security configuration inside instances
- Availability architecture
Understanding this boundary is critical.
IaaS vs Other Cloud Models
| Model | Provider Manages | Client Manages |
| IaaS | Infrastructure | OS, apps, data |
| PaaS | Infrastructure + platform | Applications |
| SaaS | Entire stack | Usage only |
IaaS offers the most flexibility among cloud service models, at the cost of greater responsibility.
IaaS and Virtualization
Most IaaS platforms rely on:
- Hypervisors
- Software-defined networking
- Software-defined storage
Some IaaS implementations also include bare metal instances, reducing abstraction while keeping cloud-style management.
IaaS and Cost Model
IaaS pricing is typically:
- Usage-based
- Metered per resource unit (CPU, RAM, storage, traffic)
- Variable depending on load and time
This enables flexibility but introduces cost unpredictability without strict controls.
Typical Use Cases for IaaS
IaaS is commonly used for:
- Application hosting
- Development and testing environments
- Scalable web services
- Migration from on-premises infrastructure
- Hybrid cloud architectures
It is less suitable for workloads requiring strict performance predictability or fixed long-term costs without careful design.
What IaaS Is Not?
❌ Not managed application hosting
❌ Not a complete solution by itself
❌ Not automatically secure
❌ Not maintenance-free
❌ Not always cheaper than dedicated infrastructure
IaaS simplifies infrastructure access, not operational responsibility.
Business Value of IaaS
For clients:
- Reduced hardware ownership
- Flexible scaling
- Easier experimentation
For providers:
- Efficient resource pooling
- Centralized infrastructure control
- Scalable service delivery
Our View of IaaS
We treat IaaS as:
- Suitable for dynamic and evolving workloads
- Something that must be architected deliberately
For stable, high-load, or cost-sensitive systems, we often combine IaaS principles with dedicated or private infrastructure to achieve predictability and control.