Infrastructure as a service (IaaS)

Infrastructure as a service (IaaS) is the cloud model in which you rent computing resources (virtual servers, storage, networking) from a provider and pay only for what you use, instead of buying and maintaining your own servers. On these resources, you install and run whatever you need: operating systems, databases, applications.

The classic definition comes from NIST, the US standards institute (SP 800-145, “The NIST Definition of Cloud Computing”): the customer can provision processing, storage, networks and other fundamental computing resources, on which it can deploy and run any software, including operating systems and applications. The customer doesn’t manage or control the underlying cloud infrastructure, but it has control over the operating systems, storage and deployed applications, plus limited control over some networking components, such as host firewalls.

What are the advantages of IaaS for a company?

Cloud infrastructure as a service provides the speed and flexibility you need to launch new services faster. IaaS lets you free up the resources your organization would otherwise spend on hosting, running and maintaining equipment. The approach is especially well suited to activities that need a lot of resources only for a while, such as development and testing.

You can build an environment that encourages innovation by simplifying and standardizing your infrastructure, with resources allocated on demand, automation and a virtual environment with advanced security features.

Choose hosted infrastructure with options for configuring firewalls and for connecting to the company network via VPN, so that your cloud servers work as an extension of the office.

In short, the advantages of IaaS are:

• no large up-front investment: you don’t buy servers; you pay monthly for the resources you use;
• fast scaling: you add memory, processors or storage in a few minutes and scale back when you no longer need them;
• no hardware worries: the provider replaces faulty components and takes care of power, cooling and the physical security of the data center;
• access from anywhere, over the internet, for employees who work from home or from other cities.

The main characteristics of cloud computing

The same NIST definition describes five essential characteristics of cloud computing, which also apply to IaaS:

• On-demand self-service: customers provision the computing resources they need on their own, such as server time or storage, automatically, without having to talk to the provider each time.
• Broad network access: resources are available over the network and can be accessed through standard mechanisms, from any device: workstations, laptops, tablets or phones.
• Resource pooling: the provider’s resources are pooled to serve multiple customers (a multi-tenant model) and are assigned and reassigned dynamically, according to demand. The customer doesn’t know the exact location of the resources but can choose, at a higher level, the country, region or data center. Examples of resources: storage, processing, memory, bandwidth.
• Rapid elasticity: resources can be scaled up or down quickly, sometimes automatically, as needed. To the customer, the available capacity seems practically unlimited.
• Measured service: cloud systems automatically measure the consumption of each type of resource (storage, processing, bandwidth, active user accounts). Usage can be monitored, controlled and reported, with transparency for both the provider and the customer.

What is the difference between IaaS, PaaS and SaaS?

The difference comes down to how much you manage yourself and how much the provider manages:

• IaaS (infrastructure as a service): the provider gives you virtual servers, storage and networking; you install and maintain the operating system and the applications. Examples: Azure Virtual Machines (Microsoft), Amazon EC2 (AWS), Google Compute Engine.
• PaaS (platform as a service): the provider also manages the operating system and the runtime environment; you take care only of the application and the data. Examples: managed databases or web application hosting platforms.
• SaaS (software as a service): you use the application directly, in the browser or in an installed program, and the provider takes care of everything else. Examples: Microsoft 365, Google Workspace, online invoicing software.

Whatever the model, responsibility is shared. The provider is responsible for the infrastructure, but the data, accounts and access rights remain the company’s responsibility. That’s why cloud servers need updates, backups and two-step verification too.

The main types of IaaS services

Here is a simple classification by type of service:

• Cloud Backup: regular data backups, stored in the cloud (see also Backup as a Service);
• Cloud Hosting: hosting websites and applications on cloud servers;
• Cloud Management: managing cloud-based infrastructure;
• Cloud Storage: storing data on cloud servers;
• Virtualization: virtual servers, most often in the client’s own data center, but also hosting, backup, storage or management solutions based on virtual machines;
• Disaster recovery (Disaster Recovery as a Service, DRaaS): copies of the company’s servers, ready to be started in the cloud if the office or the main servers become unavailable.

When does IaaS pay off for a small or medium-sized company?

IaaS pays off especially when you need to replace an old server or when you need resources for a limited period. Common examples:

• The office server is out of support. Windows Server 2012 and 2012 R2 have not received updates since October 10, 2023, and support for Windows Server 2016 ends on January 12, 2027. Before you buy a new server, it’s worth comparing it with a virtual server in the cloud.
• The accounting application or ERP has to be used from several locations. A cloud server, accessed via VPN or remote desktop, can replace the office server.
• Temporary projects: testing a new application, a migration, a busy season.

Before you move, check a few things:

• Not everything on the server needs IaaS. Files can often live directly in SharePoint and OneDrive (Microsoft 365) or in Google Drive, and email in the cloud, with no server to manage at all.
• The real monthly cost: on top of the virtual server, you usually pay separately for storage, backup, licenses and data traffic leaving the cloud.
• Where the data is stored: for personal data (GDPR), choose a region in the European Union.
• Security and backup remain the company’s responsibility, as with any server.

If you want to find out whether your company’s servers are worth moving to the cloud and what it would cost, our IT infrastructure and IT consulting team can help with the analysis, the migration and ongoing management. You can start with a free IT audit.