The industry trend is clear, but why exactly are organizations choosing to leave the mainframe and make the transition to the cloud?

1. The mainframe is at the peak of a 25-year crisis

Even before Y2K bug threatened to bring modern civilization to a screeching halt, pressure was mounting on organizations to modernize their legacy systems.  The bulk of this pressure comes from rising costs and a shortage of skilled workers.

Mainframe pricing is confusing, and the cost of the mainframe is very high because[1]:

➤ Software licensing fees are a huge financial burden, and lack of more flexible licensing options creates serious compatibility issues for any organization that requires non-proprietary add-ons or updates. Getting around these problems can even further inflate the cost as it often requires the programming of expensive applications to meet the new requirements.

➤ The mobile revolution has put a tremendous amount of pressure on existing mainframe systems in the form of a huge increase in the number of transactions. An increase in transactions means an increase in cost, and organizations are now scrambling for solutions that are more cost-effective and better able to scale with rapidly changing customer demands.

➤ Mainframe maintenance is very costly because the mainframe is often the hub of a large-scale network requiring specialist care and specific environmental factors. Older mainframes are often located in cabinets or spaces, which retain very exacting levels of temperature and humidity.

➤ The mainframe involves the recruiting of expensive technicians and engineers throughout the life of the system, a problem exacerbated by the shortage of skilled staff to execute the technologies and manage such outdated systems.

Organizations still clinging to their mainframes are facing a serious skills crisis that could cripple or even completely ruin their ability to stay competitive in the emerging digital economy.  The easy answer is to outsource the mainframe overseas; however, this only creates a new dependence and additional cost without really modernizing your system.

These concerns haven’t gone unnoticed. In the 90s and early 2000s, organizations with small and medium-sized mainframes (< 6K MIPS) began to migrate to modern, distributed systems. The lack of complexity and manageable size of these small mainframe environments made a “lift and shift” approach with extensive rewriting feasible. However, for organizations with medium to large mainframes (> 12K MIPS) such as banks, insurance companies, government agencies, and telecommunications companies, a lift and shift approach is simply not reasonable due to the volume and complexity of their code, critical nature of their applications that need 24/7 availability, as well as concerns related to the security and confidentiality of their data.

For big mainframes, phased migration of mainframe workloads, while taking measures to maximize performance on a distributed system is the only viable option.  At Raincode, we employ a number of different strategies to maximize performance, including the use of caching to reduce network latency.

2. Cloud native is a game changer for big mainframes

In new, dynamic environments such as public, private, and hybrid clouds, cloud native technologies allow enterprises to build and run scalable applications. They allow the development of loosely coupled, resilient, manageable and observable systems.  Combined with automation, they allow engineers to make frequent and predictable high-impact changes with minimal toil.[2]

Applications are becoming more and more complex as users demand more features, better responsiveness, and 100% availability.  Consumers no longer have time for sluggish, error-prone services that are frequently unavailable.  If your service is slow or unresponsive, they will simply move to a competitor.

Businesses of the future need the speed and agility provided by cloud native technologies in order to get the next big idea to market fast and meet rapidly changing consumer demands. The fastest growing companies over the last decade owe a good portion of their success to the early adoption of these technologies.

3. Mainframe workloads scale in Kubernetes


Kubernetes has become the industry standard for container orchestration and for good reason.  It’s open source, flexible and allows you to effortlessly deploy, scale, and manage containerized applications.

Designed with DevOps in mind, Kubernetes uses declarative, infrastructure-agnostic constructs to explain how programs are put together, how they interact, and how they are handled.  This allows for an order-of-magnitude improvement in the operability of modern software systems.

One of the most powerful features of Kubernetes is its ability to automatically roll-out or rollback changes to applications or application configurations so your dev team can stay on the bleeding-edge, rolling out new applications and versions while maintaining 100% availability.

As it’s platform agnostic, you can deploy on any cloud (AWS, Microsoft Azure, Google) and manage centrally with any Kubernetes service provider.  This gives your organization virtually unlimited flexibility and portability, allowing you choose the cloud infrastructure that best suits your needs, without worrying about getting locked into a closed ecosystem.

Early adopters have better ROI

Legacy modernization cannot be accomplished overnight, but Raincode compiler technologies can speed up your move to the cloud by automatically generating Docker containers from mainframe workloads, programs and related data, and deploying them on the cloud in Kubernetes.

As a CIO, the last thing you want is to be standing in front of your board of directors in three years’ time, trying to explain to them why you didn’t see the writing on the wall and implement a modernization strategy in 2020.

The time to act is now, and businesses that wait are just delaying the inevitable and losing customers in the meantime.


The fastest and easiest way to reduce mainframe OpEx is to execute your batch processes in the cloud.  We have the tools to unleash your batch in the cloud—eliminate schedule constraints and optimize your workloads.  Our Mainframe to Cloud Native solution allows large, complex mainframes with COBOL, PL/I, HLASM, JCL, and CICS applications to be migrated without transformation as consistent sets of workloads. Each set is then deployed in Kubernetes with the needed Docker containers and respective data.

For the last 20 years, we’ve been helping mainframe-based organizations modernize their legacy systems and stay ahead of the digital transformation curve.


[1] Marble, C. (2017). “Legacy Modernization: Look to the Cloud and Open Systems – InformationWeek.” 2020, from

[2] Microsoft (2020). “Defining Cloud Native.” from