Application Migration Patterns for the Service-Oriented Cloud

Moreover, the application migration to the cloud may be pursuant to this agreement consideration as part of a broader application modernization initiative, where the goal is not just to re-host the application in the cloud however to address new business and IT requirements that demand a more agile, fine-grained architecture of services and software in other words not provided by the as-is implementation.

The major risks here are that an application is modernized in isolation, and not as part of a portfolio that ensures consistent service and information architecture. Or that modernization is done primarily for technical reasons resulting in continued sub-optimal response to business change.

It is likely this will happen in stages. The business users of Application A may be unwilling to sit patiently by waiting until the migration of Application B is as well completed. There are ways to mitigate this that are beyond the scope of this innovation note. For instance, the service architecture may be developed first to act as a façade across the current applications. New solutions can at the time be assembled using these services, whilst the underlying applications are re-architected and migrated behind the scenes.

Set of required capabilities

Analysis of business requirements should identify a set of required capabilities. Current systems analysis on the existing application at that time identifies which of these capabilities could be supported by the current system in its re-architected state.

Traditionally, organizations provision and deploy the business capabilities they require on a coarse-grained whole application basis. They purchase an ERP, an HR, or CRM application for instance. But, this typically results in the tight coupling of these capabilities within these coarse-grained applications, which leads to inflexibility, and as explained before their deployment to the cloud cannot be fully optimized. In addition, with a purchased application there is no possibility for the end-user organization to re-architect.

RecommendationsIn large organizations there may be thousands of different applications in use. Many of them are non-core applications that are quite independent, serving some specific niche business or 'utility' need. These may be obvious candidates for straightforward re-hosting.

For more integrated applications and or those considered core to the business, at the time re-architecting is a more likely requirement. Core business applications should best be considered as a part of a wider application portfolio modernization strategy, and not re-architected and migrated to the cloud in isolation.

In these cases, it is important that the service architecture is considered top-down to match business requirements, not just bottom-up based on the existing applications. This is necessary to better provisioning decisions.