Which of the following migration types is best to use when migrating a highly available application, which is normally hosted on a local VM cluster, for usage with an external user population?

The scenario describes an application currently hosted on a "local VM cluster," which is an on-premises environment. The goal is to migrate it to better serve an "external user population." Migrating from an on-premises data center to a public or hybrid cloud environment is the standard approach to achieve greater scalability, high availability, and global accessibility for external users. This process is defined as an on-premises-to-cloud migration, often referred to as Physical-to-Cloud (P2C) or Virtual-to-Cloud (V2C). The cloud's inherent internet-facing infrastructure and distributed nature make it the ideal target for this requirement.

A. Cloud to on-premises: This describes repatriation, moving an application from a cloud provider back to a local data center, which is the opposite of the described scenario.
B. Cloud to cloud: This involves migrating an application between two different cloud environments. The application in the question originates from an on-premises location, not a cloud.
D. On-premises to on-premises: This describes moving an application between two local data centers. This migration type does not inherently provide the global reach and scalability needed for external users.

1. National Institute of Standards and Technology (NIST). (2011). NIST Cloud Computing Reference Architecture (NIST Special Publication 500-292).

Section 5.2

Cloud Migration

Page 23: The document defines cloud migration as "the process of moving an organization’s data and applications from the organization’s existing on-premise data center to the cloud infrastructure." This directly aligns with the scenario of moving from a local cluster to a platform suitable for external users.

2. Armbrust

M.

Fox

A.

Griffith

R.

Joseph

A. D.

Katz

R.

Konwinski

A.

... & Zaharia

M. (2009). Above the Clouds: A Berkeley View of Cloud Computing (Technical Report No. UCB/EECS-2009-28). University of California

Berkeley.

Section 3

Classes of Utility Computing: The paper discusses the economic and technical advantages of moving applications to the cloud

particularly for services that need to scale to serve a large

variable user base

which is characteristic of an "external user population." This supports the rationale for an on-premises-to-cloud migration.

3. Microsoft Azure Documentation. (2023). What is the Cloud Adoption Framework?

"Define strategy" and "Plan" sections: The framework outlines the motivations for moving to the cloud

including "reaching new customers" and "expanding to new geographies." It explicitly details the process of migrating workloads from on-premises environments to the Azure cloud to achieve these goals. This vendor documentation validates the on-premises-to-cloud path for serving external populations.