SDIA definition
We define cloud infrastructure as the paradigm on the separation of digital resources (computing power, networking and storage) from the physical infrastructure (servers, data center, energy) and providing those resources as a consumable commodity to software applications.
Other definitions
VMWare defines cloud infrastructure as:
Cloud computing infrastructure is the collection of hardware and software elements needed to enable cloud computing. It includes computing power, networking, and storage, as well as an interface for users to access their virtualized resources. The virtual resources mirror a physical infrastructure, with components like servers, network switches, memory and storage clusters.
GAIA-X defines cloud infrastructure or cloud computing as:
Cloud computing refers to offering, using and charging for IT services in a way that is dynamically adapted to demand and supplied through a network. The breadth of the services offered in the cloud-computing context encompasses the whole spectrum of information technology – among other things, infrastructure (e.g. processing capacity, storage space), platforms and software.
In the 2008 article “a view of cloud computing,” Michael Armbrust et al. define cloud infrastructure as:
Cloud computing refers to both the applications delivered as services over the Internet and the hardware and systems software in the data centers that provide those services.
Armbrust et al. explain that the cloud can most easily be categorized by the manner of its accessibility
The data center hardware and software is what we will call a cloud. When a cloud is made available in a pay-as-you-go manner to the general public, we call it a public cloud; the service being sold is utility computing. We use the term private cloud to refer to internal data centers of a business or other organization, not made available to the general public, when they are large enough to benefit from the advantages of cloud computing that we discuss here.