Legacy software goes cloud. Here’s how

Migrating legacy software to the cloud

Cloud: all well and good. But what about large, monolithic IT applications or entire IT landscapes – can they even be moved to the cloud? And if so, is it worth it? The answer: Yes, it is possible. And yes, it is also worthwhile – most of all if you go about it the right way. Because that’s when legacy software benefits most from the advantages of the cloud.

Good reasons to move legacy software to the cloud:

  • Agility: Maintenance, hosting and operation are agile in the cloud. This means that all resources can be switched on and off in sync with actual demand.
  • Cost efficiency: The result is significantly higher cost efficiency, since you only pay for the resources that are actually in operation.
    Availability: Software in the cloud is highly available – thanks to smart load balancing, operations remain fluid and performant even during peak loads.
  • Failure safety: Automated site reliability engineering (SRE) also ensures that even in the event of an error or attack, ongoing operations are not impaired.
  • Resilience: It also follows that the cloud is particularly resilient to errors or attacks and recovers quickly from disruptions and the like.
  • Future viability: Software is only as future viable as it is flexibly adaptable. The cloud ensures maximum scalability in terms of changing requirements. New features and functions can be integrated at will and without downtime (CI/CD).

There are many ways to transform historically grown legacy software into a modern cloud architecture. One possible challenge here is often databases, whose data treasure has grown over the years and should not be lost under any circumstances. However, the effort involved can be well compensated for if we embed cloud projects in a sensible strategy and use them as an opportunity to “clean out” and modernize the entire IT ecosystem.

From our practical experience, we can advise: Take inventory: check where a migration is worthwhile and where not. With a bird’s eye view of the entire IT landscape in the company, we recommend sorting according to this pattern:

  • Dispose: Applications you no longer need should be gotten rid of anyway.
  • Preserve: Keep applications that add real value in the current status quo as is.
  • Replace: You replace applications whose function can also be covered more efficiently by others (existing or new).
  • Transform: You migrate applications that have potential for the future to the cloud.

The assignment of individual applications to the appropriate cluster should be based on criteria that take into account technical aspects such as maintainability, scalability, efficiency and security as well as commercial factors – operating costs, criticality, costs, benefits.

Replace and transform

Replace and transform strategically and choose wisely:


  • Standard software: always makes sense if the business processes to be mapped are not very complex and the suitability of such solutions is correspondingly high. This is the case if the processes are not very specific and are common across all industries. A gap analysis can be helpful in determining the suitability for your own business case.
  • New development: For applications whose functionality is highly specialized or for which there is no suitable solution on the market, a new development can be considered. While this approach is more costly and time-consuming, it is well worth it if you get an intelligent and customized solution in return.


A transformation can preserve the logic and functionality of the application while enabling hosting in the cloud. After all, what is still running in an on-premise environment today can be modernized cost-effectively through transformation.

When weighing up the two options – transformation or redevelopment – practice shows that transformation can usually be tailored more cost-effectively to the respective business case and enables faster modernization towards a cloud-native architecture. If, on the other hand, the focus is on a sustainable architecture for the finished cloud solution, a new development is preferable.

First check, then decide

The first thing to do is to weigh things up carefully and then decide on the cloud strategy that best suits the individual. As is often the case, there is rarely a one-fits-all solution. Important factors in the decision-making process are:

  • Security & data protection
    • How confidential is the data to be processed?
    • Are data protection guidelines to be observed (compliance)?
  • Size and complexity of IT ecosystem
    • Degree of networking of the subsystems
    • Dependence on interfaces
    • Synchronous or asynchronous data processing

Transformation for the cloud

Modern cloud platforms offer an ecosystem of services and components to renew and migrate legacy software step by step to a modern cloud architecture.

In practice, it has been shown that those parts of the application that bring the greatest benefit to the business should be modernized and migrated first. In this way, quick successes can be achieved and resources can be used efficiently. The results are often surprising.

Provided the framework conditions permit and the unlimited computing power of the cloud platforms can be used through parallelization, batch runtimes, for example, can be drastically reduced and costs significantly lowered.

Continuous Integration

Continuous modernization is a process that combines fast, low-risk, fully automated code and data migration with the ability to modernize without disrupting ongoing operations. The technical terms for this are Continuous Integration and Continuous Delivery (CI/CD) and you are probably familiar with them.

The advantage of this approach is that all components of the application remain available at all times during modernization and migration – without downtime, without interruption. In the process, the standard functions provided by the cloud platform can be integrated and development can be switched to an agile approach using modern DevOps methods.

Another strength of this approach, as mentioned above, is the fact that modernization can be targeted where it will bring the greatest benefit. This is also important because, in most cases, only 30 percent of an application is used on a regular basis. This approach is therefore also an opportunity to decouple individual components of an application as required and move them separately to the cloud. On the one hand, this is a very good way of compensating for peaks in utilization of the legacy systems, and on the other hand, it reduces unused capacities and saves operating costs.


Companies can and should carefully evaluate their legacy software and IT landscapes and check where a move to the cloud makes sense and is important. And since there is no one and only way to replace applications that have grown over decades, it is always advisable to have an experienced IT partner at your side as a relocation helper, in addition to a structured approach.

Feel free to contact us!

Jule Witte

Jule Witte

Presse & Kommunikation
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