Migrating Applications to the Cloud

Chapter 2. What Is Cloud Migration?

Cloud migration describes the process of moving some or all of an organization’s business applications from the on-premises data center to virtual cloud infrastructure or to cloud services of some kind.

Cloud “infrastructure” takes any of several forms. The most well-known is that of the public cloud, which describes a cloud infrastructure service that is accessible via the internet and which is usually owned and operated by a “hyperscale” cloud provider. (Hyperscale describes the ability of a cloud architecture to scale elastically in response to changing demands—for example, to seamlessly allocate new compute or storage resources as required.) Another common type of cloud infrastructure is the private cloud, which is installed in an organization’s on-premises data center.

Deployments that span both public and private cloud contexts are called hybrid clouds. Today, hybrid clouds constitute the single most common deployment scenario, although cloud-to-cloud (called multicloud) and cloud-to-cloud-to-on-premises (hybrid multicloud) deployments are also common.¹

One of the most common cloud migration scenarios entails moving a portion of an organization’s on-premises applications, services, and data to a public cloud infrastructure as a service (IaaS), which is roughly analogous to the on-premises data center. Other common variations are cloud software as a service (SaaS) and platform as a service (PaaS); these are application and platform services ...