A composable infrastructure is a framework whose physical compute, storage and network fabric resources are treated as services. In a composable infrastructure, resources are logically pooled so that administrators don't have to physically configure hardware to support a specific software application. Instead, the software’s developer defines the application’s requirements for physical infrastructure using policies and service profiles and then the software uses application programming interface (API) calls to create (compose) the infrastructure it needs to run on bare metal, as a virtual machine (VM) or as a container.
A composable infrastructure negates the need for IT administrators to be concerned with the physical location of infrastructure components. Instead, a framework defines what the individual objects "of composure" are -- and each object exposes information about itself through a management API. Then, when a software application requests infrastructure to run, available services are located through an automated discovery process and resources are allocated on demand. When an infrastructure resource is no longer required, it is re-appropriated so it can be allocated to another application that needs it.
The goal of a composable infrastructure is to allow an enterprise data center to use its own physical infrastructure in a more cost-effective manner by reducing waste and the amount of time it takes to deploy a new application. Several vendors, including HP Enterprise and Cisco are promoting the concept as a way for internal IT departments to provision workloads just as quickly and efficiently as public cloud service providers can, while still maintaining control over the infrastructure that supports mission-critical applications in a private cloud setting. The concept of pooling physical infrastructure resources and building infrastructure logically is supported by the growing popularity of software-defined networking (SDN), object storage, converged infrastructure and DevOps.
As of this writing, there are no agreed-upon standards for deploying a composable infrastructure and different vendors and proponents are describing composable infrastructure by different names -- including programmable infrastructure, intelligent infrastructure, software-defined infrastructure, Infrastructure as Code (IaC), decoupled infrastructure and hardware disaggregation.