The transition from products to services is impacting software delivery as well. Previously, development companies built software products, and delivered them to customers who took responsibility for operations. With the advent of cloud, the majority of companies that build software also operate it on their customers’ behalf.
Software as service is happening at all layers of the IT stack. At the bottom, Infrastructure-as-a-Service delivers on-demand virtual machines, networks, and storage. Platform-as-a-Service delivers on-demand databases, caches, workflow engines, and application containers. Software-as-a-Service delivers on-demand business functionality. At every level, providers allow customers to consume services based on demand, pay for them based on consumption, and offload responsibility for their management to the provider.