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Cloud & operations

What is IaaS (Infrastructure as a Service)?

IaaS is rented IT infrastructure in the cloud: servers, storage and networking as consumption. See the difference between IaaS, PaaS and SaaS.

In short

IaaS (Infrastructure as a Service) is the cloud model where you rent the infrastructure itself (virtual servers, storage and networking) from a cloud provider such as Microsoft Azure and pay according to consumption.

The provider owns and operates the data centre, the hardware and the virtualisation layer; you remain responsible for operating systems, updates, security and applications, exactly as on your own servers, just without owning iron. IaaS is thus the lowest of the three cloud layers: with PaaS the provider also takes over the platform (database, runtime environment), and with SaaS you rent the finished application.

For businesses, IaaS is typically the bridge away from the on-premises server room: existing servers can be moved almost 1:1 to the cloud when the hardware is due for replacement, or when the VMware licences go up. The gains are scalability, predictable economics and goodbye to hardware responsibility. MI Support IT helps Danish businesses move and operate infrastructure in Azure.

Back to the glossary

What is IaaS?

IaaS (Infrastructure as a Service) means renting IT infrastructure as a service: virtual servers, disk and networking, delivered from a cloud provider's data centre and billed by consumption. What you used to buy as physical servers with 5-year depreciation becomes an operating cost that can be scaled up and down. The provider is responsible up to and including the hypervisor; everything above (operating system, patching, security, applications) is still your responsibility (or your operations partner's).

IaaS vs. PaaS vs. SaaS

The three models differ in how much the provider takes responsibility for:

ModelThe provider deliversYou handle yourselfExample
IaaSHardware, networking, virtualisationOS, updates, applications, dataVirtual machines in Azure
PaaS+ platform: database, runtime environmentApplications and dataAzure SQL Database
SaaSThe finished applicationUsers, data and configurationMicrosoft 365

The rule of thumb: SaaS where it exists, PaaS where you build yourself, IaaS for everything that "is just a server" and needs to be moved as is. Most businesses end up with a mix of all three.

Azure as IaaS

For Danish SMBs, Microsoft Azure is the natural IaaS choice: virtual machines run the same Windows Server and Active Directory roles as on-premises, identity ties in with Microsoft 365 via Entra ID, and existing servers can be migrated almost 1:1 with Azure Migrate. On top of that comes what is expensive to build yourself: redundant data centres (including in the EU), built-in backup and disaster recovery, and security monitoring across it all. The bill does require management, though: rightsizing of machines, reservations and shutdown schedules are the difference between a good and an ugly Azure invoice.

When does IaaS make sense for an SMB?

The typical triggers:

  • The hardware is due for replacement: instead of investing in new servers, the workloads are moved to Azure. It becomes the last time you have to make that decision.
  • The VMware renewal has gone up: migrating to the cloud often beats an expensive licence purchase, see hypervisor.
  • Line-of-business systems with no SaaS version: older applications that require "a Windows server" can live on as IaaS, even when everything else is SaaS.
  • Fluctuating demand: seasonal load or growth, where capacity must be able to scale up without a procurement round.

Conversely: if the system exists as SaaS, that is almost always the better answer. Do not move a server you do not need to own at all.

How MI Support IT can help

MI Support IT helps with the entire journey: assessing what should be IaaS, PaaS or SaaS, migration to Azure and subsequent operations, security and cost management. See cloud and hosting. Contact us before the next server purchase or VMware renewal.

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