How to Modernize Legacy Systems with Microservices ArchitecturesHow to Modernize Legacy Systems with Microservices Architectures

By Vijayasekhar Duvvur

Microservices architectures break down an application's functions into smaller, containerized systems that communicate through application programming interfaces (APIs). They represent a rapidly growing development model with continued cloud and serverless computing innovations and offer a transformative approach to modernizing legacy systems. Microservices help organizations achieve greater scalability, agility, and resilience over the traditional monolithic applications used by many legacy systems.

That said, it's vital to understand the challenges of moving to a microservices-based architecture when necessary and know the best practices for designing, developing, and deploying microservices-based solutions. By considering overall needs, comparing benefits and risks, and modeling an implementation strategy, organizations can decide whether migrating to a microservices architecture is the right choice for modernizing their legacy systems.

Why Migrate to Microservices

Scalability and agility are two significant benefits of a microservices architecture. With monolithic applications, it's difficult to isolate and scale distinct application functions under variable loads. Even if a monolithic application is scaled to meet increased demand, it could take months of time and capital to reach the end goal. By then, the demand might have changed —or disappear altogether — and the application will waste resources, bogging down the larger operating system.

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On the other hand, microservices solutions allow individual application components to scale quickly, according to their specific demand. Because microservices architectures use containerization to separate application functions, developers can quickly and efficiently apply functional changes to individual application components as needed. This makes each application inherently more flexible and able to deliver its services without sacrificing quality or scalability. This is especially true when microservices architectures are run through cloud-native solutions because they provide a template for the cloud provider to re-create the app at any volume. The application developer doesn't need to invest in new hardware, lengthy code revisions, or labor costs that often come with maintaining monolithic applications at scale.

Finally, microservices architectures make applications more resilient. Because monolithic applications function on a single codebase, a single error during an update or maintenance can create large-scale problems. Microservices-based applications, however, work around this issue. Because each function runs on its own codebase, it's easier to isolate and fix problems without disrupting the rest of the application's services.

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Challenges of Microservices Migration

Microservices might seem like a one-size-fits-all, no-downsides approach to modernizing legacy systems, but the first step to any major system migration is to understand the pros and cons. No major project comes without challenges, and migrating to microservices is no different.

For instance, personnel might be resistant to changes associated with microservices. Many employees are likely comfortable working with the legacy systems and their applications, and migrating might seem like an unneeded, complicated change. Team members might also have valid concerns about the time and cost of service decomposition. Regardless of the reasons, it behooves organizational leaders and advocates to actively listen to these kinds of concerns and to provide training and resources to guarantee a smooth transition.

Beyond human obstacles, data integration and security present two significant logistical challenges for microservices architectures, with most chief experience officers listing them as the primary challenges. Since microservices distribute services across multiple containers, developers must ensure each service is secure. They must also observe a wealth of data across all services to guarantee quality and consistency. The energy spent on data encryption, monitoring, auditing, logging, and troubleshooting required to maintain secure and functioning microservices architectures successfully is a serious jump from simple monoliths. As such, it's imperative for organizations to ensure they have the resources and staffing needed to prevent downtime, cyberattacks, and data corruption across all their microservices applications.

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Effective Strategies for Moving to Microservices

Because migrating to microservices comes with a fair share of serious challenges, it isn't a decision to make lightly. Microservices architectures are best suited for complex applications that require multiple, scalable services and functions. If an organization hosts primarily simple applications with focused, streamlined services, moving to microservices architectures might be an unnecessary cost. But, if a company is ready to make the jump, the organization should follow a structured, patient approach to decomposing their systems' monolithic architectures.

The Bottom Line: Proceed with Care

With all the buzz surrounding microservices architectures being used by high-profile organizations, it's easy for developers to assume they're the best option. It's also tempting to think that due to their increased scalability, agility, and resilience, microservices are a one-size-fits-all approach to the many difficulties of updating legacy systems. While microservices-based solutions are often appropriate for an organization's needs, it's imperative for developers and team leaders to develop in-depth technical and functional knowledge before deciding to migrate. Considering the often indispensable roles they've taken on for years, modernizing legacy systems should never be a casual endeavor, but, like many large-scale projects, with the proper patience, preparation, and cooperation, the shift to a microservices-based architecture can prove invaluable.  

About the Author:

Vijayasekhar Duvvur is a software modernization specialist with over 19 years of experience in the software industry. He specializes in AI, ML, and cybersecurity and has a proven track record of leveraging cutting-edge technologies to modernize legacy systems. Vijayasekhar holds a bachelor's degree in computer science and engineering and a Master of Technology degree in bioinformatics. He is an IEEE senior member, a regular industry speaker, and an awards judge. Connect with Vijayasekhar on LinkedIn.