What Is Legacy Application Modernization?

Hello Folks, welcome back to Learnizo Global. Legacy application modernization is when an outdated application is updated or rebuilt to effectively work in modern runtime environments and with other applications. Legacy applications were made with now outdated technologies that make it hard to update, improve, and transport the application.

These applications are usually slow to be replaced with a more modern version because they are critical to an organization’s business operations. Reasons organizations undertake modernizations instead of buying or building a completely new application include:

• There is no application on the market that fits all of an organization’s needs.
• The application is a key part of an organization’s product portfolio.
• There are security regulations that are best adhered to with the current application.

However, there are legitimate reasons to simply replace the legacy application. For example, an organization might deem rebuilding an application more resource-intensive than practical. In which case, building or buying a new application makes better use of available resources. Or, the gap between the state of the legacy application and where it needs to be could be large enough that the underlying technology cannot be turned into a modern application.

Modernizing a legacy application often involves reworking the code to varying degrees. Sometimes it is just to make the legacy application work with APIs. The other extreme is coding a new version of the legacy application from scratch.

An effective method for modernizing legacy applications is to rebuild them to have a cloud-native architecture. While this results in an application that is ready to take advantage of modern cloud environments, it requires heavy investments in time, money, and skill.

The Cost of Maintaining Legacy Applications

Maintaining legacy applications can take up a lot of time, labor, and money. And since these applications are harder to update, security issues can arise as new threats quickly evolve.

Legacy applications consume a significant portion of a budget and labor. However, to go through legacy application modernization is to invest a comparably significant amount of budget into hiring skilled personnel and the labor and resources they need to modify or rebuild a legacy application. An IT department may not have the resources to keep legacy applications running as well as invest in legacy application modernization. This forces the department to make difficult decisions for what to fund and to what extent.

Legacy and Modern Applications

Legacy applications typically are monolithic, meaning they are single-tier software applications where all the pieces of the applications are built into one platform. In a monolithic application, there’s no clear separation between the different elements of the applications. The result is in order to update one piece of the application; a new version of the entire application needs to be rolled out. Similarly, a bug in one element can affect the overall functionality and be difficult to pinpoint and fix. Overall, the monolithic nature demands upkeep, and maintenance on legacy applications can be incredibly cumbersome and slow.

In contrast, modern applications usually are broken down into loosely coupled, individual services called Microservices. The Microservices are stored in containers, which are runtime environments that have only the elements of an operating system (OS) needed to run a Microservice.

Modernizing Legacy Applications

Microservices are housed in containers. Containers are small software packages that only have the necessary parts of an OS to run a specific Microservice and nothing more. Because they are smaller, they can be scaled more easily because copying those takes less time. Containers are what allow a Microservice to be replaced and rolled back. With a management platform like Kubernetes, containers can be isolated and individually updated across multiple servers in rolling updates.

Cloud-native applications use this architecture. They are called cloud native because they are designed specifically to run in a cloud. Cloud-native applications are made of loosely-coupled Microservices. That means individual or groups of Microservices can be isolated and worked on by developers individually. The overall application is therefore not disrupted and unrelated Microservices are not significantly affected.

Things to Consider When Updating a Legacy Application

An organization shouldn’t start adapting an old application into a modern one without a well-thought-out plan on how to do so and what budget to assign to it. Formulating the plan isn’t a simple task, however. IT department budgets aren’t always deep wells that permit the department to comfortably fund both the maintenance of legacy applications at the same time as the development of a modern application.

An organization should determine what its goals are for going through legacy application modernization. One goal could be to move to the cloud and leverage all of the cloud’s functions requiring a full modernization. Another goal could be to simply move the application to the cloud as quickly as possible. By lifting-and-shifting, as this is called, money can be saved on data center operation and maintenance, to minimize disruption of services, and have some form of relatively greater scalability. Lifting-and-shifting requires minimal changes to the application, if any.

With those goals in mind, an organization should then define the issues it needs to address with its legacy application. Some parts of the legacy application could be more essential than others. Some parts of the legacy application are degrading the customer experience and will need improvement alongside modernization.

Organizations don’t want to go through all of this trouble just to have the same issue in the future. That’s why they should research modern technologies and approaches that can be easily updated.

Using virtualized infrastructure along with open source code can be one way to do this. Virtualized infrastructures, such as Microservices, are separated from the hardware they reside on and can be updated more easily than hardware-based infrastructures.

An organization’s developers and dedicated open source developers together are continuously working open source code. This ensures the code being used in the application is being maintained and fixed on a constant basis from a diverse group of people with different perspectives. To keep the modern application’s code up to date, simply download new versions from an open source library, integrate it with the application, and publish an update.

Any changes done to the application should be documented in detail. Having detailed documentation means when issues in the modern application’s code arise later, they can more easily be addressed because the DevOps teams can investigate the documentation and find the exact source of the problem. Poor documentation may be one reason reworking a legacy application can be so difficult, especially when the developers who made the legacy application no longer work for the organization.

It is particularly important for organizations to ensure they have the skill base in their IT departments to perform legacy application modernization. Again, this is especially the case when the original developers aren’t around. Options available to organizations include upskilling existing employees, hiring new employees, or partnering with a cloud migration organization.

Upskilling existing employees may be the most cost-effective approach but requires the employees to go through training processes, which take time. It is up to the organization to research the amount of time this takes and if the organization would rather hire new employees or work with a third party.

Legacy Application Modernization and the Cloud

Running applications in the cloud has increasingly become the norm. Legacy applications do not run well in the cloud without being changed. One example of an approach for legacy application modernization that does not prepare the application for the cloud is lifting and shifting. This is where minor changes or APIs are applied to the application before it is sent to a cloud environment.

There are benefits that come with moving legacy applications to the cloud from on-premises data centers. Primarily, the cloud is less difficult for organizations to work with and maintain, because of services from the cloud provider. Operating costs are also much lower because an organization can only pay for the resources it uses and doesn’t have to conduct maintenance on the physical infrastructure.

Customer experience also improves when an organization fully modernizes its legacy application and makes it cloud-native. This is because any issues with the application that would otherwise disrupt service can be fixed faster and with more granularities.

Another reason to move from legacy to cloud-native applications is to keep up with changing infrastructures and new technologies. An organization’s IT team can make APIs that allow the application to communicate with a new infrastructure. There is a mitigated risk of changes to the application itself containing bugs; however, there is a risk the APIs will be faulty.

This is a particular risk if the personnel working with the legacy application were not the original developers and don’t have quality documentation to understand the complexities of the legacy application. Additionally, by simply placing the legacy application in the cloud, the application cannot utilize all of the cloud’s features. This results in organizations spending more on the cloud than they otherwise would.

There are different degrees in which to work with legacy applications to transform them into something that can run in a cloud. The names for these different approaches are refactoring, revise, rebuilding, retirement, and replacement. Rebuilding a legacy application is the approach that most fits true legacy application modernization. It is when an application is rewritten or re-architected from the ground up, sometimes by using a cloud provider’s platform-as-a-service coding tools.