Organizations hoping to relocate applications into the cloud have five preferences: rehost on infrastructure as a service (IaaS), refactor for platform as a service (PaaS), revise for IaaS or PaaS, rebuild on PaaS, or replace with software as a service (SaaS), according to a report by Gartner Inc, an information technology research and advisory corporation providing technology related insight.

In a research report, Research director Richard Watson said architects often face difficult situations when they are asked to move applications to cloud. The decision they take has to consider the company’s requirements and criteria and there is a bigger need for alternative ideas.

The company, however, puts forward strategies which the IT organizations can consider while moving applications to cloud, the report said.

Rehost entails redeploying applications to a different hardware environment and change the application’s infrastructure configuration. Rehosting an application without making changes to its form can offer a fast cloud migration solution. However, its primary advantage is that teams can migrate systems quickly, without modifying their architecture.

Refactor runs applications on a cloud provider’s infrastructure. The chief advantage is amalgamating familiarity with innovation as “backward-compatible”. PaaS means developers can reclaim languages, frameworks, and containers they have invested in, thus, initiating codes the organization considers strategic. Disadvantages include missing capabilities, transitive risk, and framework lock-in.

Revise requires amend or extend the existing code base to support legacy modernization requirements and then use rehost or refactor options to deploy to cloud. This option allows organizations to optimize the application to leverage the cloud characteristics of providers' infrastructure.

Rebuilding the solution on PaaS, discarding code for an existing application and restructuring the application -- requires losing the familiarity of existing code and frameworks. The benefit of rebuilding an application is access to innovative features in the provider's platform. They improve developer efficiency with tools that allow application templates and data models to be customized, metadata-driven engines, and communities that supply pre-built mechanism.

Replace requires abandoning an existing application (or set of applications) and use commercial software delivered as a service. This option avoids investment in assembling a development team when requirements for a business operation changes. Disadvantages can include inconsistent data semantics, data access issues, and vendor lock-in.

“Choosing the optimal application-migration option is a decision that cannot be made in isolation,” Watson said on the company website.

“Any cloud-migration decision is, in essence, an application or infrastructure modernization decision and needs to be approached in the broader context of related application portfolio management and infrastructure portfolio management programs,” he added.

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