What Is Infrastructure as a Service (IaaS) ?

IaaS is a cloud computing service model that makes on-demand compute, storage, and networking functionality available via an internet connection, on a pay-as-you-go basis. Rather than buying, installing, and managing physical servers and IT infrastructure, IaaS solutions allow businesses to access computing resources offered by a third-party provider that is responsible for managing, maintaining, and upgrading the infrastructure.

In the IaaS model, a cloud service provider (CSP) manages large data centers, typically located around the world, with physical machines and virtualized resources that can make servers, virtual machines (VMs), storage, and networking services available to customers over the web. Customers rent access to these cloud infrastructure resources on a pay-as-you-go basis, using as much or as few services as they need at any given moment. The CSP is responsible for managing and maintaining the cloud infrastructure, minimizing the burden on in-house IT teams. With IaaS, businesses can also avoid the cost of building, maintaining, securing, and providing heating and cooling for data centers that would normally host these computing resources on site.

IaaS offerings fall into three categories:

• Compute resources. With IaaS offerings, businesses can access the essential hardware that every computer requires for processing: central processing units (CPUs), graphical processing units (GPUs), and random access memory (RAM).
• Data storage. IaaS providers offer access to block storage, file storage, and object storage technologies.
• Networking. These resources include virtualized routers, switches, and load balancers.

• Reduce capital expense. With IaaS, there is no upfront cost required to purchase and install equipment in a physical data center.
• Manage and optimize costs. The pay-per-service pricing offered by IaaS providers allows businesses to pay only for the infrastructure services they need, reducing operational costs and optimizing IT budgets.
• Scale easily. IaaS solutions give businesses heightened scalability, allow them to add or minimize resources quickly to meet business needs, and accelerate speed to market.
• Increase reliability. An IaaS platform eliminates the single point of failure — if one component within a cloud environment fails, the redundant nature of the cloud means that IaaS services will still be available.
• Improve security. Most IaaS vendors are able to offer stronger and more advanced security for computing infrastructure than businesses can achieve in-house.
• Gain agility. The IaaS model allows businesses to provision the resources they need within minutes or hours, rather than days or weeks, increasing their ability to respond quickly to market conditions and business opportunities.

• Security risks. Relying on a third-party provider to manage infrastructure and the data associated with it represents a certain loss of control, requiring IT teams to trust the security controls of the cloud service provider.
• Lack of customization. IaaS solutions may be less customizable than in-house technologies.
• Vendor lock-in. As businesses become reliant on IaaS providers, changing vendors can be costly and time-consuming, leading to a certain amount of vendor lock-in.
• Connectivity issues. As with any cloud computing solution, poor connectivity or internet outages can impact the performance of processes dependent on IaaS infrastructure.
• Lack of transparency. Because IT teams do not have access to infrastructure in IaaS solutions, gaining visibility into performance and security can be more difficult, making systems management more complex.
• Competition for resources. Because virtualization enables IaaS providers to provide infrastructure for multiple customers from the same physical server, bandwidth for one customer may be impacted by compute-intensive activity from another customer.

IaaS is a mature computing model that first became popular about a decade ago. Although it faces competition from newly emerging technologies, it is currently the most common cloud computing paradigm.

IaaS cloud providers, such as Akamai, offer IaaS services from their extensive pool of physical servers in their data centers. These vendors use a hypervisor, also known as a virtual machine monitor (VMM), to create the virtual service. A hypervisor is a type of emulator that runs on an actual hardware host, which is referred to as the host machine. It runs a virtual machine (VM) that mimics an actual server or network. Some common types of hypervisors include Xen, Oracle VirtualBox, Oracle VM, KVM, and VMware ESX.

The most common way of creating an IaaS VM is by using cloud orchestration technologies such as OpenStack or Apache CloudStack. These programs choose a hypervisor to run the VM on and then create the virtual machine. They also frequently allocate storage and add firewalls, logging services, and networking essentials including IP addresses. Advanced services might include clustering, encryption, billing, load balancing, and more complicated virtual local area networks (VLAN). A virtual private cloud (VPC) can assist in further isolating the cloud resources. Both central processing unit (CPU) and graphics processing unit (GPU) systems are typically available.

Customers of IaaS access their virtualized infrastructure over the internet. They use a visual dashboard or graphical user interface (GUI) to quickly create or modify devices, often with the push of a button. The dashboard can also be used to monitor performance, collect data, troubleshoot, and track costs. All services are provided on a pay-as-you-go model. Some organizations might develop their own private cloud rather than using a provider, but this model is typically only used by large technology companies.

Services can also be provisioned programmatically using APIs. This technique is often used together with infrastructure as code (IaC) technologies, which deploy the infrastructure using scripts. IaC allows users to standardize common infrastructure tasks and test their deployments using automation.

One important point about IaaS: The customer does not control the underlying physical hardware components and interconnections. These remain under the control of the cloud provider. Users of IaaS are typically responsible for the selection and installation of the operating system and all software applications, including databases and middleware.

Businesses rely on IaaS solutions for a broad range of uses.

• Testing and development. DevOps teams can quickly set up and take down environments to develop and test software, making it easier to bring applications to market faster.
• Hosting web apps. IaaS offerings deliver all the infrastructure required to support web applications, including servers, storage, and networking resources.
• High-performance computing (HPC). IaaS solutions are ideal for compute-intensive workloads like financial modeling, AI and machine learning, scientific computations, and other scenarios where massive amounts of short-term processing power are required.
• Big data analytics. IaaS can deliver the compute and processing power to manipulate and analyze extraordinarily large datasets.
• Cloud storage, backup, and recovery. Moving data storage to IaaS infrastructure can be more cost-effective and free up IT teams from managing on-site data stores.

Many IaaS providers invest heavily in security technology to protect their cloud infrastructure and the customer data that resides on it. But because IaaS services are accessed via the internet, there is a higher probability of cyberattacks. IaaS vendors may also be subject to insider attacks. Configuration mistakes by an IaaS vendor can create vulnerabilities that may be exploited by attackers. Additionally, because visibility is more limited with IaaS offerings, businesses may find it difficult to track compliance in highly regulated industries that require data to be stored in certain ways.