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Infrastructure as a service (IaaS) is acloud computing service model where a cloud services vendor provides computing resources such as storage, network, servers, andvirtualization (which emulates computer hardware). This service frees users from maintaining their owndata center,[1] but they must install and maintain the operating system and application software.[2] Iaas provides users high-levelAPIs to control details of underlying network infrastructure such as backup, data partitioning, scaling, security and physical computing resources. Services can be scaled on-demand by the user. According to theInternet Engineering Task Force (IETF), such infrastructure is the most basic cloud-service model. IaaS can be hosted in apublic cloud (where users share hardware, storage, and network devices), aprivate cloud (users do not share resources), or ahybrid cloud (combination of both).
The USNational Institute of Standards and Technology (NIST) defines infrastructure as a service as:[3]
The capability provided to the consumer is provision processing, storage, networks, as well as other fundamental computing resources where the consumer is able to deploy & run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, & deployed applications; and possibly limited control of select networking components (e.g., host firewalls).
IaaS clouds often offer additional resources such as a virtual-machinedisk-image library, rawblock storage, file orobject storage, firewalls, load balancers, IP addresses,virtual local area networks (VLANs), and software bundles.[4]
IaaS-cloud providers supply resources on-demand from the large pools of equipment installed indata centers. Forwide-area connectivity, customers can use either the Internet orcarrier clouds (dedicatedvirtual private networks, VPNs). To deploy their applications, users install operating-system images and the application software on the cloud infrastructure.[5][unreliable source?] Users patch and maintain the operating systems. IaaS services are typically billed as a utility: cost reflects the amount of resources allocated or consumed.
Typically, IaaS involves the use of acloud orchestration technology such asOpenStack,Apache CloudStack, orOpenNebula. It manages the creation of a virtual machine (VM) and decides on the hypervisor (i.e. physical host) in order to start it. Ahypervisor runsvirtual machines (VMs) as guests. Pools of hypervisors in the cloud operational system can support large numbers of virtual machines and the ability to scale services up and down according to demand by customers. Hypervisors includeXen,Oracle VirtualBox,Oracle VM,KVM,VMware ESX/ESXi, or MicrosoftHyper-V. It also enables VM migration between hosts, allocates storage volumes, and attaches them to VMs that track usage information for billing.
An alternative to hypervisors is Linuxcontainers, which run in isolated partitions of aLinux kernel that runs directly on the physical hardware. Containers are isolated, secured and managed using Linuxcgroups and namespaces. Containerisation offers higher performance than virtualization because there is no hypervisor overhead.
The global IaaS market is projected to reach a value of $411.9 billion by 2030, expanding at acompound annual growth rate (CAGR) of 22.6% from 2023 to 2030. This growth is primarily driven by the adoption of cloud-based infrastructure within the Banking, Financial Services, and Insurance (BFSI) sector, which employs these technologies to enhance scalability and reduce operational costs.[6]
TheUK Government encourages departments to use public cloud solutions as a first option. IaaS is in use within the UK Government but the technology community within government recommends consideration ofPlatform as a Service (PaaS) in cases where a department may not have IaaS skills and management capacity.[7]
