Many enterprises rely on business-critical applications running on IBM Power (IBM i (AS/400), AIX, Linux on Power) systems in their on-prem data centers. Often, these applications have been modified or customized over years or even decades to meet the unique needs of the business. Moreover, the people that developed them may in many cases no longer work at the organization. These factors not only make these applications more difficult to migrate to the cloud as part of a modernization or digital transformation strategy, but they also require organizations to consider how they will deal with accumulated technical debt.

Recent third-party product offerings have made a new solution possible in public clouds: migrate legacy or business-critical applications to the cloud and run them there natively without extensive modification. This can enable organizations to take advantage of cloud scalability and agility for these workloads while also creating an opportunity to slowly adapt and update those applications, paying off technical debt incrementally and without the disruption or expense of widescale changes.

But first, let's talk about technical debt, how it accumulates and how it can impact an organization's infrastructure and operations.

While we'd all like to believe that technical decisions are made in a completely rational manner, with an eye on the downstream consequences, in reality, that's not always the case. Organizations make changes to their software infrastructure in both planned and highly reactive ways - to address a market need, to fix problems or adapt to changing customer requirements or technology. While the implications of those changes may be understood, sometimes they're not. Often near-term benefits or problem fixes get prioritized over long-term consequences.

The distinction between intentional and unintentional technical debt is important. By definition,  intentional technical debt is incurred by choice and normally documented, so IT teams down the line understand what the issues are and what compromises may have been made to solve for an immediate need in the past. Unintentional technical debt, on the other hand, could be the result of mistakes, misunderstandings or just poorly written code. It's most likely not obvious what the consequences are when changes are made, they may not be easily discoverable and are, more than likely, undocumented.

Much like financial debt, technical debt must be paid off. If it's not, then the debt can compound over time as additional changes are made. The result? Problems become progressively harder to fix. For older systems and platforms (like the IBM i/AS/400) technical debt carries an additional complication: the teams that managed those systems may have long since moved on or retired. The loss of institutional knowledge means that even documented changes may not be simple for newer teams to comprehend.

Whether intentional or not, technical debt carries costs and operational risks. It can impact the performance of applications. And as more debt accrues, it can limit the ability of developers to add new features and updates.

All of these issues add up over time. And it leads many organizations to become reluctant to even try to migrate legacy applications to the cloud.

But as mentioned previously, there are solutions that enable organizations to extend - or "rehost" - applications by moving them to the public cloud with minimal changes to code. Once in the cloud, they can be updated incrementally using more modern software development practices to start paying off technical debt. The essentially unlimited capacity to replicate applications and data and test updates in a controlled environment minimizes the risk posed by unforeseen or unknown problems lurking in legacy code.

Over time, as technical debt is paid off, those applications can even be modernized, with individual parts rebuilt and adapted to take advantage of cloud native services and capabilities, including increased performance and capacity on demand.

In the everyday world, financial debt can limit your options; you may not be able to buy a house, finance an education or start a family. Technical debt carries different but equally serious consequences. Migrating legacy applications to the cloud can make it easier to finally pay down that debt and build a stronger foundation for the future.

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ABOUT THE AUTHOR

Matthew Romero is the Technical Product Evangelist at Skytap, the leading cloud service to run IBM Power and x86 workloads natively in the public cloud. Matthew has extensive expertise supporting and creating technical content for cloud technologies, Microsoft Azure in particular. He spent nine years at 3Sharp and Indigo Slate managing corporate IT services and building technical demos, and before that spent 4 years at Microsoft as a program and lab manager in the Server and Tools Business unit.